Publications

About 400 million tonnes of plastics are produced per annum worldwide. End-of-life of plastics disposal contaminates the waterways aquifers and limits the landfill areas. Options for recycling plastic wastes include feedstock recycling mechanical /material recycling industrial energy recovery municipal solid waste incineration. Incineration of plastics containing E-Wastes releases noxious odours harmful gases dioxins HBr polybrominated diphenylethers and other hydrocarbons. This study focusses on recycling options in particular feedstock recycling of plastics in high-temperature materials processing for a sustainable solution to the plastic wastes not suitable for recycling. Of the 7% CO₂ emissions attributed to the iron and steel industry worldwide ∼30% of the carbon footprint is reduced using the waste plastics compared to other carbon sources in addition to energy savings. Plastics have higher H₂ content than the coal. Hydrogen evolved from the plastics acts as the reductant alongside the carbon monoxide. Hydrogen reduction of iron ore in presence of plastics increases the reaction rates due to higher diffusion of H₂ compared to CO. Plastic replacement reduces the process temperature by at least 100–200 °C due to the reducing gases (hydrogen) which enhance the energy efficiency of the process. Similarly plastics greatly reduce the emissions in other high carbon footprint process such as magnesia production while contributing to energy.

Electrocatalytic water splitting is the key process for the formation of green fuels for energy transport and storage in a sustainable energy economy. Besides electricity it requires water an aspect that seldomly has been considered until recently. As freshwater is a limited resource (<1% of earth's water) lately plentiful reports were published on direct seawater (around 96.5% of earth's water) splitting without or with additives (buffers or bases). Alternatively the seawater can be split in two steps where it is first purified by reverse osmosis and then split in a conventional water electrolyser. This quantitative analysis discusses the challenges of the direct usage of non-purified seawater. Further herein we compare the energy requirements and costs of seawater purification with those of conventional water splitting. We find that direct seawater splitting has substantial drawbacks compared to conventional water splitting and bears almost no advantage. In short it is less promising than the two-step scenario as the capital and operating costs of water purification are insignificant compared to those of electrolysis of pure water.

Photovoltaic (PV) is promising to supply power for residential buildings. Battery is the most widely employed storage method to mitigate the intermittence of PV and to overcome the mismatch between production and load. Hydrogen storage is another promising method that it is suitable for long-term storage. This study focuses on the comparison of self-sufficiency ratio and cost performance between battery storage and hydrogen storage for a residential building in Sweden. The results show that battery storage is superior to the hydrogen storage in the studied case. Sensitivity study of the component cost within the hydrogen storage system is also carried out. Electrolyzer cost is the most sensitive factor for improving system performance. A hybrid battery and hydrogen storage system which can harness the advantages of both battery and hydrogen storages is proposed in the last place.

The Hy4Heat Safety Assessment has focused on assessing the safe use of hydrogen gas in certain types of domestic properties and buildings. The summary reports (the Precis and the Safety Assessment Conclusions Report) bring together all the findings of the work and should be looked to for context by all readers. The technical reports should be read in conjunction with the summary reports. While the summary reports are made as accessible as possible for general readers the technical reports may be most accessible for readers with a degree of technical subject matter understanding. All of the safety assessment reports have now been reviewed by the HSE.<br/><br/>This document is an overview of the Safety Assessment work undertaken as part of the Hy4Heat programme

Sustainability transportation is characterized by a positive externality on the environment health social security land use and social inclusion. The increasing interest in global warming has caused attention to be paid to the introduction of the hydrogen bus (H2B). When introducing new environmental technologies such as H2B it is often necessary to assess the environmental benefits related to this new technology. However such benefits are typically non-priced due to their public good nature. Therefore we have to address this problem using the contingent valuation (CV) method. This method has been developed within environmental economics as a means to economically assess environmental changes which are typically not traded in the market. So far several big cities have been analyzed to evaluate the perceived benefit related to H2B introduction but to the best of our knowledge no one has performed a CV analysis of a historical city where smog also damages historical buildings. This paper presents the results obtained using a multi-wave survey. We have investigated user preferences to elicit their willingness to pay for H2B introduction in Perugia taking into account all types of negative externalities due to the traffic pollution. The results confirm that residents in Perugia are willing to pay extra to support the introduction of H2B.

The transition to hydrogen as a fuel source presents several challenges. One of the major hurdles is the cost-effective production of hydrogen in small quantities (less than 1MMscf/month). In the early demonstration phase hydrogen can be provided by bulk distribution of liquid or compressed gas from central production plants; however the next phase to fostering the hydrogen economy will likely include onsite generation and extensive pipeline networks to help effect a pervasive infrastructure. Providing inexpensive hydrogen at a fleet operator’s garage or local fuelling station is a key enabling technology for direct hydrogen Fuel Cell Vehicles (FCVs). The objective of this project was to develop a comprehensive turnkey stand-alone commercial hydrogen fuelling station for FCVs with state-of-the-art technology that is cost-competitive with current hydrocarbon fuels. Such a station would promote the advent of the hydrogen fuel economy for buses fleet vehicles and ultimately personal vehicles. Air Products partnering with the U.S. Department of Energy (DOE) The Pennsylvania State University Harvest Energy Technology and QuestAir developed a turnkey hydrogen fuelling station on the Penn State campus. Air Products aimed at designing a station that would have 65% overall station efficiency 82% PSA (pressure swing adsorption) efficiency and the capability of producing hydrogen at $3.00/kg (gge) H₂ at mass production rates. Air Products designed a fuelling station at Penn State from the ground up. This project was implemented in three phases. The first phase evaluated the various technologies available in hydrogen generation compression storage and gas dispensing. In the second phase Air Products designed the components chosen from the technologies examined. Finally phase three entailed a several-month period of data collection full-scale operation maintenance of the station and optimization of system reliability and performance. Based on field data analysis it was determined by a proprietary hydrogen-analysis model that hydrogen produced from the station at a rate of 1500 kg/day and when produced at 1000 stations per year would be able to deliver hydrogen at a price of $3.03/kg (gge) H₂. The station’s efficiency was measured to be 65.1% and the PSA was tested and ran at an efficiency of 82.1% thus meeting the project targets. From the study it was determined that more research was needed in the area of hydrogen fuelling. The overall cost of the hydrogen energy station when combined with the required plot size for scaled-up hydrogen demands demonstrated that a station using steam methane reforming technology as a means to produce on–site hydrogen would have limited utility in the marketplace. Alternative hydrogen supplies such as liquid or pipeline delivery to a refuelling station need to be included in the exploration of alternative energy site layouts. These avenues need to be explored before a definitive refuelling station configuration and commercialization pathway can be determined.

Green hydrogen produced by power‐to‐gas will play a major role in the defossilization of the energy system as it offers both carbon‐neutral chemical energy and the chance to provide flexibility. This paper provides an extensive analysis of hydrogen production in decentralized energy systems as well as possible operation modes (H2 generation or system flexibility). Modelling was realized for municipalities—the lowest administrative unit in Germany thus providing high spatial resolution—in the linear optimization framework OEMOF. The results allowed for a detailed regional analysis of the specific operating modes and were analyzed using full‐load hours share of used negative residual load installed capacity and levelized cost of hydrogen to derive the operation mode of power‐to‐gas to produce hydrogen. The results show that power‐to‐gas is mainly characterized by constant hydrogen production and rarely provides flexibility to the system. Main drivers of this dominant operation mode include future demand for hydrogen and the fact that high full‐load hours reduce hydrogen‐production costs. However changes in the regulatory market and technical framework could promote more flexibility and support possible use cases for the central technology to succeed in the energy transition.

In order to favor a transition to a renewable energy economy it is necessary to study the possible permeation of renewable energy sources not only in the electric grid or industrial scale but also in the small householding scale. One of the most interesting technologies available for this purpose is solar energy since it is a mature technology that can be easily installed in every rooftop. Thus a techno-economic assessment was carried out to evaluate the installation of a solar-based power-heat hybrid microgrid considering the use of hydrogen as an energy vector in a typical residential house in Spain. Lead-acid batteries plus the photovoltaic and solar thermal energy installation are complemented with a hydrogen system composed of an electrolyzer two metal hydride bottles and a fuel cell. A simulation tool has been generated using experimental models developed and validated with real equipment for each one of the electric microgrid component. Three operating modes were tested making use of this tool to better manage the energy consumed/produced and optimize the economic output of the facility. The results show that setting up a hydrogen-based microgrid in a residential house is unviable today mainly due to the high cost of hydrogen generation and consumption equipment. If only solar energy is considered the microgrid inversion (12.500 €) is recovered in ten years. On the other hand selling the electricity output has almost no repercussions considering current electrical rates in Spain. Finally while using an optimization algorithm to manage energy use battery life-spam and economic benefit slightly increase. However this profit may not be enough to justify the use of a more complex control system. The results of this research will help users renewable energy companies investigators and policymakers to better understand the different factors influencing the spread of renewable smart grids in households and propose solutions to address these.

Stress corrosion cracking (SCC) of steels can reduce the structural integrity of gas pipelines. To simulate in-service degradation of pipeline steels in laboratory the method of accelerated degradation consisted in subjecting specimens to electrolytic hydrogenation to loading up the certain plastic deformation and heating of specimen at 250°C was recently developed. The purpose of this paper was to analyse mechanical and SCC behaviour of in-service and in-laboratory degraded gas pipeline steels and to reveal some fractographic features of SCC. Three pipeline steels of the different strength (17H1S which is equivalent of API X52 API X60 and API X70) were investigated. The characteristics of the as-received pipeline steels with different strength were compared with the properties of pipeline steels after in-service and in-laboratory degradation. An influence of the NS4 solution on SCC resistance of 17H1S and API X60 steels in the as-received state and after the accelerated degradation using slow strain rate tension method was analysed. The noticeable decrease of plasticity for 17H1S and API X60 steels after long-term operation was shown. Deep microdelaminations revealed in the central part of fracture surfaces for the operated steels can be considered as the signs of dissipated damaging in the metal caused by texture and hydrogen absorbed by metal. Comparison of the SCC tests results showed that the characteristics of both steels in the as-received state were insignificantly changed under the influence of the environment. At the same time the degraded steels were characterized by a high sensitivity to SCC. It was shown fractographically that it associated with cracking along interfaces of ferrite and pearlite grains with secondary deep intergranular cracks formation and also by delamination between ferrite and cementite inside pearlite grains. The similar fracture mechanism at SCC tests was revealed for near the outer surface of the specimens and in the central part of the fracture surfaces of in-laboratory degraded specimens. These results demonstrated the key role of hydrogen during SCC and in-bulk cracking as well.

Pressure is mounting on the natural gas and LNG community to reduce methane emissions and this is most urgent in EU countries following the adoption of much tougher greenhouse gas reduction targets of 2030 and the publication of the European Commission’s Methane Strategy. With rapidly declining indigenous EU production and therefore rising import dependence there are increasing calls for emissions from imported pipeline gas and LNG to be quantified and based on actual measurements as opposed to standard emission factors. The Methane Strategy promises to be a significant milestone in that process. Companies which are supplying (or intending to supply) natural gas to the EU – the largest global import market for pipeline gas and a very significant market for LNG – would be well advised to pay close attention to how the regulation of methane emissions is unfolding and to make an immediate and positive response. Failure to do so could accelerate the demise of natural gas in European energy balances faster than would otherwise have been the case and shorten the time available for transition to decarbonised gases – specifically hydrogen – using existing natural gas infrastructure.<br/>This EU initiative will (and arguably already has) attracted attention from non-EU governments and companies involved in global gas and LNG trade. We have already seen deliveries of `carbon neutral’ LNG cargos to Asia as well as a long-term LNG contract in which the greenhouse gas content of cargos will be measured reported and verified (MRV) according to an agreed methodology. Natural gas and LNG exports if based on these standards or those set out in the EU Methane Strategy may be able to command premium prices from buyers eager to demonstrate their own GHG reduction credentials to governments customers and civil society.

To ensure the UK’s net zero targets are met the transition from conventionally fueled transport to low emission alternatives is necessary. The impact from increased decarbonised electricity generation on ecosystem services (ES) and natural capital (NC) are not currently quantified with decarbonisation required to minimise impacts from climate change. This study aims to project the future electric and hydrogen energy demand between 2020 and 2050 for car bus and train to better understand the land/sea area that would be required to support energy generation. In this work predictions of the geospatial impact of renewable energy (onshore/offshore wind and solar) nuclear and fossil fuels on ES and NC were made considering generation mix number of generation installations and energy density. Results show that electric transport will require ~136599 GWh for all vehicle types analysed in 2050 much less than hydrogen transport at ~425532 GWh. We estimate that to power electric transport at least 1515 km2 will be required for solar 1672 km2 for wind and 5 km2 for nuclear. Hydrogen approximately doubles this requirement. Results provide an approximation of the future demands from the transport sector on land and sea area use indicating that a combined electric and hydrogen network will be needed to accommodate a range of socio-economic requirements. While robust assessments of ES and NC impacts are critical in future policies and planning significant reductions in energy demands through a modal shift to (low emission) public transport will be most effective in ensuring a sustainable transport future.

Currently hydrogen is mainly produced through steam reforming of natural gas. However this conventional process involves environmental and energy security concerns. This has led to the development of alternative technologies for (potentially) green hydrogen production. In this work the environmental and energy performance of biohydrogen produced in Europe via steam reforming of glycerol and bio-oil is evaluated from a life-cycle perspective and contrasted with that of conventional hydrogen from steam methane reforming. Glycerol as a by-product from the production of rapeseed biodiesel and bio-oil from the fast pyrolysis of poplar biomass are considered. The processing plants are simulated in Aspen Plus® to provide inventory data for the life cycle assessment. The environmental impact potentials evaluated include abiotic depletion global warming ozone layer depletion photochemical oxidant formation land competition acidification and eutrophication. Furthermore the cumulative (total and non-renewable) energy demand is calculated as well as the corresponding renewability scores and life-cycle energy balances and efficiencies of the biohydrogen products. In addition to quantitative evidence of the (expected) relevance of the feedstock and impact categories considered results show that poplar-derived bio-oil could be a suitable feedstock for steam reforming in contrast to first-generation bioglycerol.

An update on the proposed commercial frameworks for transport and storage power and industrial carbon capture business models.

This report is commissioned by the Henry Royce Institute for advanced materials as part of its role around convening and supporting the UK advanced materials community to help promote and develop new research activity. The overriding objective is to bring together the advanced materials community to discuss analyse and assimilate opportunities for emerging materials research for economic and societal benefit. Such research is ultimately linked to both national and global drivers namely Transition to Zero Carbon Sustainable Manufacture Digital & Communications Circular Economy as well as Health & Wellbeing.

This paper can be download from their website

This standard has been created for the specific purposes of the Hy4Heat programme. The standard was commissioned in 2018 and this version was considered and approved by the relevant IGEM committees in May of 2020. This version of the standard was developed using the latest publicly available information at that time and may include some conservative requirements which further research may deem not necessary. The supplement will be updated regularly following the publication of new research into the application of hydrogen.



This Reference Standard aims to identify and discuss the principles required for the safety and integrity of Hydrogen installation and utilisation in premises.



This document intends to:

• provide a point of reference for those requiring an understanding of the implications of using hydrogen as a distributed gas in properties
• detail the characteristics of Hydrogen
• detail the comparisons between hydrogen and Natural Gas (NG)
• discuss the safety implications of using hydrogen
• discuss the implications for materials when using hydrogen
• discuss the implications for the installation and use of using hydrogen in domestic & smaller commercial buildings.

The standard is available to download through the IGEM website here.

It is time that hydrogen moves from an afterthought to a central pillar of the energy system and its key role in delivering climate neutrality means it merits a dedicated framework. It becomes paramount to allow hydrogen to express its full potential as the other leg of the energy mobility and industry transitions. The proposed “Hydrogen Act” is not a single piece of legislation it is intended to be a vision for an umbrella framework aimed at harmonising and integrating all separate hydrogen-related actions and legislations. It focuses on infrastructure and market aspects describing three phases of development: the kick-start phase the ramp-up phase and the market-growth phase.

Hydrogen Fuelling Infrastructure Research and Station Technology (H2FIRST) is a project initiated by the DOE in 2015 and executed by Sandia National Laboratories and the National Renewable Energy Laboratory to address R&D barriers to the deployment of hydrogen fuelling infrastructure. One key barrier to the deployment of fuelling stations is the land area they require (i.e. ""footprint""). Space is particularly a constraint in dense urban areas where hydrogen demand is high but space for fuelling stations is limited. This work presents current fire code requirements that inform station footprint then identifies and quantifies opportunities to reduce footprint without altering the safety profile of fuelling stations. Opportunities analyzed include potential new methods of hydrogen delivery as well as alternative placements of station technologies (i.e. rooftop/underground fuel storage). As interest in heavy-duty fuelling stations and other markets for hydrogen grows this study can inform techniques to reduce the footprint of heavy-duty stations as well.



This work characterizes generic designs for stations with a capacity of 600 kg/day hydrogen dispensed and 4 dispenser hoses. Three base case designs (delivered gas delivered liquid and on-site electrolysis production) have been modified in 5 different ways to study the impacts of recently released fire code changes colocation with gasoline refuelling alternate delivery assumptions underground storage of hydrogen and rooftop storage of hydrogen resulting in a total of 32 different station designs. The footprints of the base case stations range from 13000 to 21000 ft².



A significant focus of this study is the NFPA 2 requirements especially the prescribed setback distances for bulk gaseous or liquid hydrogen storage. While the prescribed distances are large in some cases these setback distances are found to have a nuanced impact on station lot size; considerations of the delivery truck path traffic flow parking and convenience store location are also important. Station designs that utilize underground and rooftop storage can reduce footprint but may not be practical or economical. For example burying hydrogen storage tanks underground can reduce footprint but the cost savings they enable depend on the cost of burial and the cost land. Siting and economic analysis of station lot sizes illustrate the benefit of smaller station footprints in the flexibility and cost savings they can provide. This study can be used as a reference that provides examples of the key design differences that fuelling stations can incorporate the approximate sizes of generic station lots and considerations that might be unique to particular designs.

European countries approach the market ramp-up of hydrogen very differently. In some cases the economic and political starting points differ significantly. While the probability is high that some countries such as Germany or Italy will import hydrogen in the long term other countries such as United Kingdom France or Spain could become hydrogen exporters. The reasons for this are the higher potential for renewable energies but also a technology-neutral approach on the supply side.

Hydrogen produced from renewables works as an energy carrier and as energy storage medium and thus hydrogen can help to overcome the intermittency of typical renewable energy sources. However there is no comprehensive environmental performance study of hydrogen production and consumption. In this study detailed cradle to grave life cycle analyses are performed in an isolated territory. The hydrogen is produced on-site by Polymer Electrolyte Membrane (PEM) water electrolysis based on electricity from wind turbines that would otherwise have been curtailed and subsequently transported with gas cylinder by road and ferry. The hydrogen is used to provide electricity and heat through fuel cell stacks as well as hydrogen fuel for fuel cell vehicles. In order to evaluate the environmental impacts related to the hydrogen production and utilisation this work conducts an investigation of the entire life cycle of the described hydrogen production transportation and utilisation. All the processes related to the equipment manufacture operation maintenance and disposal are considered in this study.

Climate change and environmental degradation are an existential threat to Europe and the world. To overcome these challenges Europe needs a new growth strategy that will transform the Union into a modern resource-efficient and competitive economy where

• there are no net emissions of greenhouse gases by 2050
• economic growth is decoupled from resource use
• no person and no place is left behind

The European Green Deal is our plan to make the EU's economy sustainable. We can do this by turning climate and environmental challenges into opportunities and making the transition just and inclusive for all



The European Green Deal provides an action plan to

• boost the efficient use of resources by moving to a clean circular economy
• restore biodiversity and cut pollution

The plan outlines investments needed and financing tools available. It explains how to ensure a just and inclusive transition.



The EU aims to be climate neutral in 2050. We proposed a European Climate Law to turn this political commitment into a legal obligation.



Reaching this target will require action by all sectors of our economy including

• investing in environmentally-friendly technologies
• supporting industry to innovate
• rolling out cleaner cheaper and healthier forms of private and public transport
• decarbonising the energy sector
• ensuring buildings are more energy efficient
• working with international partners to improve global environmental standards

The EU will also provide financial support and technical assistance to help those that are most affected by the move towards the green economy. This is called the Just Transition Mechanism. It will help mobilise at least €100 billion over the period 2021-2027 in the most affected regions.

Effects of microstructural changes induced by prestraining on hydrogen transport and hydrogen embrittlement (HE) of austenitic stainless steels were studied by hydrogen precharging and tensile testing. Prestrains higher than 20% at 20 °C significantly enhance the HE of 304L steel as they induce severe α′ martensite transformation accelerating hydrogen transport and hydrogen entry during subsequent hydrogen exposure. In contrast 304L steel prestrained at 50 and 80 °C and 316L steel prestrained at 20 °C exhibit less HE due to less α′ after prestraining. The increase of dislocations after prestraining has a negligible influence on apparent hydrogen diffusivity compared with pre-existing α′. The deformation twins in heavily prestrained 304L steel can modify HE mechanism by assisting intergranular (IG) fracture. Regardless of temperature and prestrain level HE and apparent diffusivity ( Dapp ) increase monotonously with α′ volume fraction ( f_α′ ). D_app can be described as log D_app=log(D_α′s_α′/s_γ)+log[f_α′/(1−f_α′)] for 10%<f_α′<90% with Dα′ is diffusivity in α′ s_α′ and s_γ are solubility in α′ and austenite respectively. The two equations can also be applied to these more typical duplex materials containing both BCC and FCC phases.

The paper presents a sustainable electric powertrain for a transit city bus featuring an electrochemical battery-free power unit consisting of a hydrogen fuel cell stack and a kinetic energy storage system based on high-speed flywheels. A rare-earth free high-efficiency motor technology is adopted to pursue a more sustainable vehicle architecture by limiting the use of critical raw materials. A suitable dynamic energetic model of the full vehicle powertrain has been developed to investigate the feasibility of the traction system and the related energy management control strategy. The model includes losses characterisation as a function of the load of the main components of the powertrain by using experimental tests and literature data. The performance of the proposed solution is evaluated by simulating a vehicle mission on an urban path in real traffic conditions. Considerations about the effectiveness of the traction system are discussed.

Niobium microalloying is the backbone of modern low-carbon high strength low alloy (HSLA) steel metallurgy providing a favorable combination of strength and toughness by pronounced microstructural refinement. Molybdenum alloying is established in medium-carbon quenching and tempering of steel by delivering high hardenability and good tempering resistance. Recent developments of ultra-high strength steel grades such as fully martensitic steel can be optimized by using beneficial metallurgical effects of niobium and molybdenum. The paper details the metallurgical principles of both elements in such steel and the achievable improvement of properties. Particularly the underlying mechanisms of improving toughness and reducing the sensitivity towards hydrogen embrittlement by a suitable combination of molybdenum and niobium alloying will be discussed.

Metastable austenitic stainless steels (ASSs) have excellent ductility but low strength so that their usage as load-bearing components is significantly limited. Rolling is an effective method of increasing strength whereas the effect of rolling temperature on microstructural evolution the hydrogen embrittlement (HE) sensitivity and fracture mechanisms is still unclear. In present study the effect of cold/warm rolling on detailed microstructural characteristics of 304 ASS was quantitatively investigated and the corresponding HE sensitivity was evaluated via slow strain rate test. The results suggest that cold-rolling led to high strength but poor plasticity and deteriorated HE sensitivity while warm-rolled samples provided combination of high strength and ductility and also superior HE resistance. Compared with 18% α′-martensite in cold -rolled steel warm-rolled specimens consisted of complete austenite less twins and lower dislocation density，moreover the favorable {112} ND and {110} ND textures replaced the harmful {001} ND texture. Based on in-situ EBSD observation during SSRT the HE sensitivity was governed by the combined effect of pre-deformation microstructures and the dynamic microstructural evolution. Advanced method of time-of-flight secondary ion mass spectrometry was used to observe the distribution of hydrogen and the hydrogen content of specimens was determined by the gas chromatograph thermal desorption analysis method. An exceedingly small amount of hydrogen entered the warm-rolled samples while a large amount of hydrogen was trapped at grain boundaries of cold-rolled sample leading to complete intergranular fracture. Therefore warm rolling is an effective pathway for obtaining high combination of strength and ductility together with excellent HE sensitivity.

The report documents current knowledge of the social issues surrounding hydrogen projects. It reviews leading practice stakeholder engagement and communication strategies and findings from focus groups and research activities across Australia.

The full report can be found at this link.

This paper deals with the concept of micro-fracture map (MFM) and its role in structural integrity evaluations in materials science and engineering on the basis of previous research by the author on notch-induced fracture and hydrogen embrittlement of progressively cold drawn pearlitic steels and 316L austenitic stainless steel. With regard to this some examples are provided of assembly of MFMs in particular situations.

We have studied hydrogen gas production using photocatalysis from C2-C5 carbon chain polyols cyclic alcohols and mono and di-saccharides using palladium nanoparticles supported on a TiO2 catalyst. For many of the polyols the hydrogen evolution rate is found to be dictated by the number of hydroxyl groups and available a-hydrogens in the structure. However the rule only applies to polyols and cyclic alcohols while the sugar activity is limited by the bulky structure of those molecules. There was also evidence of ring opening in photocatalytic reforming of cyclic alcohols that involved dehydrogenation and decarbonylation of a CC bond.

A nuclear reactor pressure vessel (NRPV) wall is formed by two layer of different materials: an inner layer of stainless steel (cladding material) and an outer layer of low carbon steel (base material) which is highly susceptible to corrosion related phenomena. A reduction of the mechanical properties of both materials forming the wall would appear due to the action of the harsh environment causing hydrogen embrittlement (HE) related phenomena. As a result of the manufacturing process residual stresses and strains appear in the NRPV wall thereby influencing the main stage in HE: hydrogen diffusion. A common engineering practice for reducing such states is to apply a tempering heat treatment. In this paper a numerical analysis is carried out for revealing the influence of the heat treatment parameters (tempering temperature and tempering time) on the HE of a commonly used NRPV. To achieve this goal a numerical model of hydrogen diffusion assisted by stress and strain was used considering diverse residual stress-strain states after tempering. This way the obtained hydrogen accumulation during operation time of the NRPV provides insight into the better tempering conditions from the structural integrity point of view.

The UK Government signed legislation on 27th June 2019 committing the UK to a legally binding target of Net Zero emissions by 2050. Climate change is one of the most significant technical economic social and business challenges facing the world today.

The H21 NIC Phase 1 project delivered an optimally designed experimentation and testing programme supported by the HSE Science Division and DNV GL with the aim to collect quantifiable evidence to support that the UK distribution network of 2032 will be comparably as safe operating on 100% hydrogen as it currently is on

natural gas. This innovative project begins to fill critical safety evidence gaps surrounding the conversion of the UK gas network to 100% hydrogen. This will facilitate progression towards H21 Phase 2 Operational Safety Demonstrations and the H21 Phase 3 Live Trials to promote customer acceptability and ultimately aid progress towards a government policy decision on heat.

DNV GL and HSE Science Division were engaged to undertake the experimentation testing and QRA update programme of work. DNV GL and HSE Science Division also peer reviewed each other’s programme of work at various stages throughout the project undertaking a challenge and review of the experimental data and results to provide confidence in the conclusions.

A strategic set of tests was designed to cover the range of assets represented across the Great Britain gas distribution networks. The assets used in the testing were mostly recovered from the distribution network as part of the ongoing Iron Mains Risk Reduction Replacement Programme. Controlled testing against a well-defined master testing plan with both natural gas and 100% hydrogen was then undertaken to provide the quantitative evidence to forecast any change to background leakage levels in a 100% hydrogen network.

Key Findings from Phase 1a:

• Of the 215 assets tested 41 of them were found to leak 19 of them provided sufficient data to be able to compare hydrogen and methane leak rates.
• The tests showed that assets that were gas tight on methane were also gas tight on hydrogen. Assets that leaked on hydrogen also leaked
• on methane including repaired assets.
• The ratio of the hydrogen to methane volumetric leak rates varied between 1.1 and 2.2 which is largely consistent with the bounding values expected for laminar and turbulent (or inertial) flow which gave ratios of 1.2 and 2.8 respectively.
• None of the PE assets leaked; cast ductile and spun iron leaked to a similar degree (around 26-29% of all iron assets leaked) and the proportion of leaking steel assets was slightly less (14%).
• Four types of joint were responsible for most of the leaks on joints: screwed lead yarn bolted gland and hook bolts.
• All of the repairs that sealed methane leaks also were effective when tested with hydrogen.

The U.S. energy system is evolving as society and technologies change. Renewable electricity generation—especially from wind and solar—is growing rapidly and alternative energy sources are being developed and implemented across the residential commercial transportation and industrial sectors to take advantage of their cost security and health benefits. Systemic changes present numerous challenges to grid resiliency and energy affordability creating a need for synergistic solutions that satisfy multiple applications while yielding system-wide cost and emissions benefits. One such solution is an integrated hydrogen energy system (Figure ES-1). This is the focus of H₂@Scale—a U.S. Department of Energy (DOE) initiative led by the Office of Energy Efficiency and Renewable Energy’s Hydrogen and Fuel Technologies Office. H₂@Scale brings together stakeholders to advance affordable hydrogen production transport storage and utilization in multiple energy sectors. The H₂@Scale concept involves hydrogen as an energy intermediate. Hydrogen can be produced from various conventional and renewable energy sources including as a responsive load on the electric grid. Hydrogen has many current applications and many more potential applications such as energy for transportation—used directly in fuel cell electric vehicles (FCEVs) as a feedstock for synthetic fuels and to upgrade oil and biomass—feedstock for industry (e.g. for ammonia production metals refining and other end uses) heat for industry and buildings and electricity storage. Owing to its flexibility and fungibility a hydrogen intermediate could link energy sources that have surplus availability to markets that require energy or chemical feedstocks benefiting both. This document builds upon a growing body of analyses of hydrogen as an energy intermediate by reporting the results from our initial analysis of the potential impacts of the H₂@Scale vision by the mid-21st century for the 48 contiguous U.S. states. Previous estimates have been based on expert elicitation and focused on hydrogen demands. We build upon them first by estimating hydrogen’s serviceable consumption potential for possible hydrogen applications and the technical potential for producing hydrogen from various resources. We define the serviceable consumption potential as the quantity of hydrogen that would be consumed to serve the portion of the market that could be captured without considering economics (i.e. if the price of hydrogen were $0/kg over an extended period); thus it can be considered an upper bound for the size of the market. We define the technical potential as the resource potential constrained by real-world geography and system performance but not by economics. We then compare the cumulative serviceable consumption potential with the technical potential of a number of possible sources. Second we estimate economic potential: the quantity of hydrogen at an equilibrium price at which suppliers are willing to sell and consumers are willing to buy the same quantity of hydrogen. We believe this method provides a deeper understanding than was available in the previous analyses. We develop economic potentials for multiple scenarios across various market and technology-advancement assumptions.

This study seeks to find the appropriate strategies necessary to make sustainable and effective hydrogen energy investments. Within this scope nine different criteria are defined regarding social managerial and financial factors. A hesitant interval-valued intuitionistic fuzzy (IVIF) decision-making trial and evaluation laboratory (DEMATEL) methodology is considered to calculate the degree of importance of the criteria. Additionally impact relation maps are also generated to visualize the causality relationship between the factors. The findings indicate that the technical dimension has the greatest importance in comparison to managerial and financial factors. Furthermore it is also concluded that storage and logistics research and development and technological infrastructure are the most significant factors to be considered when defining hydrogen energy investment strategies. Hence before investing in hydrogen energy necessary actions should be taken to minimize the storage and logistic costs. Among them building the production site close to the usage area will contribute significantly to this purpose. In this way possible losses during the transportation of hydrogen can be minimized. Moreover it is essential to identify the lowest-cost hydrogen storage method by carrying out the necessary research and development activities thereby increasing the sustainability and effectiveness of hydrogen energy investment projects.

Twinning-induced plasticity (TWIP) steels have higher strength and ductility than conventional steels. Deformation mechanisms producing twins that prevent gliding and stacking of dislocations cause a higher ductility than that of steel grades with the same strength. TWIP steels are considered to be within the new generation of advanced high-strength steels (AHSS). However some aspects such as the corrosion resistance and performance in service of TWIP steel materials need more research. Application of TWIP steels in the automotive industry requires a proper investigation of corrosion behavior and corrosion mechanisms which would indicate the optimum degree of protection and the possible decrease in costs. In general Fe−Mn-based TWIP steel alloys can passivate in oxidizing acid neutral and basic solutions however they cannot passivate in reducing acid or active chloride solutions. TWIP steels have become as a potential material of interest for automotive applications due to their effectiveness impact resistance and negligible harm to the environment. The mechanical and corrosion performance of TWIP steels is subjected to the manufacturing and processing steps like forging and casting elemental composition and thermo-mechanical treatment. Corrosion of TWIP steels caused by both intrinsic and extrinsic factors has posed a serious problem for their use. Passivity breakdown caused by pitting and galvanic corrosion due to phase segregation are widely described and their critical mechanisms examined. Numerous studies have been performed to study corrosion behaviour and passivation of TWIP steel. Despite the large number of articles on corrosion few comprehensive reports have been published on this topic. The current trend for development of corrosion resistance TWIP steel is thoroughly studied and represented showing the key mechanisms and factors influencing corrosion processes and its consequences on TWIP steel. In addition suggestions for future works and gaps in the literature are considered.

The iron and steel industry is one of the world’s largest industrial emitters of greenhouse gases. One promising option for decarbonising the industry is hydrogen direct reduction of iron (H-DR) with electric arc furnace (EAF) steelmaking powered by zero carbon electricity. However to date little attention has been given to the energy system requirements of adopting such a highly energy-intensive process. This study integrates a newly developed long-term energy system planning tool with a thermodynamic process model of H-DR/EAF steelmaking developed by Vogl et al. (2018) to assess the optimal combination of generation and storage technologies needed to provide a reliable supply of electricity and hydrogen. The modelling tools can be applied to any country or region and their use is demonstrated here by application to the UK iron and steel industry as a case study. It is found that the optimal energy system comprises 1.3 GW of electrolysers 3 GW of wind power 2.5 GW of solar 60 MW of combined cycle gas with carbon capture 600 GWh/600 MW of hydrogen storage and 30 GWh/130 MW of compressed air energy storage. The hydrogen storage requirements of the industry can be significantly reduced by maintaining some dispatchable generation for example from 600 GWh with no restriction on dispatchable generation to 140 GWh if 20% of electricity demand is met using dispatchable generation. The marginal abatement costs of a switch to hydrogen-based steelmaking are projected to be less than carbon price forecasts within 5–10 years.

Hydrogen is often described as the fuel of the future especially for application in hydrogen powered fuel-cell vehicles (HFCV’s). However its widespread implementation in this role has been thwarted by the lack of a lightweight safe on-board hydrogen storage material. Here we show that benign readily available hydrocarbon wax is capable of rapidly releasing large amounts of hydrogen through microwave-assisted catalytic decomposition. This discovery offers a new material and system for safe and efficient hydrogen storage and could facilitate its application in a HFCV. Importantly hydrogen storage materials made of wax can be manufactured through completely sustainable processes utilizing biomass or other renewable feedstocks.

Liquid organic hydrogen carriers (LOHC) store hydrogen by reversible hydrogenation of a carrier material. Water can enter the system via wet hydrogen coming from electrolysis as well as via moisture on the catalyst. Removing this water is important for reliable operation of the LOHC system. Different approaches for doing this have been evaluated on three stages of the process. Drying of the hydrogen before entering the LOHC system itself is preferable. A membrane drying process turns out to be the most efficient way. If the water content in the LOHC system is still so high that liquid–liquid demixing occurs it is crucial for water removal to enhance the slow settling. Introduction of an appropriate packing can help to separate the two phases as long as the volume flow is not too high. Further drying below the rather low solubility limit is challenging. Introduction of zeolites into the system is a possible option. Water adsorbs on the surface of the zeolite and moisture content is therefore decreased.

Recent modeling efforts of non-equilibrium effects in detonations have suggested that hydrogen-based detonations may be affected by vibrational non-equilibrium of the hydrogen and oxygen molecules effects which could explain discrepancies of cell sizes measured experimentally and calculated without relaxation effects. The present study addresses the role of vibrational relaxation in 2H2/O2 detonations by considering two-bath gases argon and helium. These two gases have the same thermodynamic and kinetic effects when relaxation is neglected. However due to the bath gases differences in molecular weight and reduced mass differences which affect the molecular collisions relaxation rates can be changed by approximately 50-70%. Experiments were performed in a narrow channel in mixtures of 2H2/O2/7Ar and 2H2/O2/7He to evaluate the role of the bath gas on detonation cellular structures. The experiments showed differences in velocity deficits and cell sizes for experimental conditions keeping the induction zone length constant in each of the mixtures. These differences were negligible in sensitive mixtures but increased with the increase in velocity deficits while the cell sizes approaching the channel dimensions. Near the limits differences of cell size in two mixtures approached a factor of 2. These differences were however reconciled by accounting for the viscous losses to the tube walls evaluated using a modified version of Mirels' laminar boundary layer theory and generalized Chapman-Jouguet theory for eigenvalue detonations. The experiments suggest that there is an influence of relaxation effects on the cellular structure of detonations which is more sensitive to wall boundary conditions. However the previous works showed that the impact of vibrational non-equilibrium in a mixture of H2/Air is more visible due to the effects of N2 in the air slowest to relax. Previous discrepancies suggested to be indicative of relaxation effects should be reevaluated by the inclusion of wall loss effects.

This research activity aims at investigating the hydrogen embrittlement of Maraging steels in connection to real sudden failures of some of the suspension blades of the Virgo Project experimental apparatus. Some of them failed after 15 years of service in working conditions. Typically in the Virgo detector blades are loaded up to 50-60% of the material yield strength. For a deeper understanding of the failure the relationship between hydrogen concentration and mechanical properties of the material have been investigated with specimens prepared in order to simulate blade working conditions. A mechanical characterization of the material has been carried out by standard tensile testing in order to establish the effect of hydrogen content on the material strength. Further experimental activity was executed in order to characterize the fracture surface and to measure the hydrogen content. Finally some of the failed blades have been analyzed in DICI-UNIPI laboratory. The experimental results show that the blades failure can be related with the hydrogen embrittlement phenomenon.

Hydrogen as carbon-free fuel is a very promising candidate for climate-neutral internal combustion engine operation. In comparison to other renewable fuels hydrogen does obviously not produce CO2 emissions. In this work two concepts of hydrogen internal combustion engines (H2 -ICEs) are investigated experimentally. One approach is the modification of a state-of-the-art gasoline passenger car engine using hydrogen direct injection. It targets gasoline-like specific power output by mixture enrichment down to stoichiometric operation. Another approach is to use a heavy-duty diesel engine equipped with spark ignition and hydrogen port fuel injection. Here a diesel-like indicated efficiency is targeted through constant lean-burn operation. The measurement results show that both approaches are applicable. For the gasoline engine-based concept stoichio-metric operation requires a three-way catalyst or a three-way NOX storage catalyst as the primary exhaust gas aftertreatment system. For the diesel engine-based concept state-of-the-art selective catalytic reduction (SCR) catalysts can be used to reduce the NOx emissions provided the engine calibration ensures sufficient exhaust gas temperature levels. In conclusion while H2 -ICEs present new challenges for the development of the exhaust gas aftertreatment systems they are capable to realize zero-impact tailpipe emission operation.

The reduction of greenhouse gas emissions has entered regulatory agendas in shipping. In Norway a debate has been ongoing for over a decade about whether liquefied natural gas (LNG) ship fuel enables or impedes the transition to a greener future for shipping. This paper explores the assembling of ship fuel before and after the introduction of a controversial carbon tax on LNG. It reconstructs how changes in the regulatory apparatus prompted the reworking of natural gas into a ship fuel yet later slowed down the development of LNG in a strategy to promote alternative zero-emission fuels such as hydrogen. Following ship fuel as socio-materiality in motion we find that fossil fuels are reworked into new modes of application as part of transition policies. Natural gas continues to be enacted as an “enabler of transition” in the context of shipping given that current government policies work to support the production of hydrogen from natural gas and carbon capture and storage (CCS). New modes of accounting for emissions reassemble existing fossil fuel materiality by means of CCS and fossil-based zero-emission fuels. We examine retrofit as a particular kind of reassembling and as a prism for studying the politics of fuel and the relation between transitions and existing infrastructures.

The Innovate UK KTN Hydrogen Innovation Network is bringing you this second episode with Steffan Eldred and Simon Buckley from Innovate UK KTN who continue their ‘back to basics' approach and delve deeper to understand where hydrogen should be used with their special guest Joanna Richart Head of Hydrogen Business at Ricardo. As with any technology or fuel discussions can get carried away implying they are the solution to all things but at Innovate UK KTN we strongly believe that we should ensure hydrogen is used where it can be most effective for decarbonising energy industrial and chemical industries.



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Energies based on biomaterials attract a lot of interest as next-generation energy because biomaterials are environmentally friendly materials and abundant in nature. Fuel cells are also known as the clean and important next-generation source of energy. In the present study to develop the fuel cell based on biomaterials a novel biofuel cell which consists of collagen electrolyte and the hydrogen fuel generated from photochemical system II (PSII) in photosynthesis has been fabricated and its property has been investigated. It was found that the PSII solution in which PSII was extracted from the thylakoid membrane using a surfactant generates hydrogen by the irradiation of light. The typical hydrogen-generating rate is approximately 7.41 × 1014 molecules/s for the light intensity of 0.5 mW/cm2 for the PSII solution of 5 mL. The biofuel cell using the PSII solution as the fuel exhibited approximately 0.12 mW/cm2 . This result indicates that the fuel cell using the collagen electrolyte and the hydrogen fuel generated from PSII solution becomes the new type of biofuel cell and will lead to the development of the next-generation energy

Hydrogen is considered a promising energy carrier for a sustainable future when it is produced by utilizing renewable energy. Nowadays less than 4% of hydrogen production is based on electrolysis processes. Each component of a hydrogen energy system needs to be optimized to increase the operation time and system efficiency. Only in this way hydrogen produced by electrolysis processes can be competitive with the conventional fossil energy sources. As conventional electrolysers are designed for operation at fixed process conditions the implementation of fluctuating and highly intermittent renewable energy is challenging. Alkaline water electrolysis is a key technology for large-scale hydrogen production powered by renewable energy. At low power availability conventional alkaline water electrolysers show a limited part-load range due to an increased gas impurity. Explosive mixtures of hydrogen and oxygen must be prevented; thus a safety shutdown is performed when reaching specific gas contamination. The University of Pisa is setting up a dedicated laboratory including a 40-kW commercial alkaline electrolyser: the focus of the study is to analyze the safety of the electrolyser together with its performance and the real energy efficiency analyzing its operational data collected under different operating conditions affected by the unstable energy supply.

Non-electrified regional railway lines with typically employed diesel-electric multiple units require alternative propulsion systems to meet increasingly strict emissions regulations. With the aim to identify an optimal alternative to conventional diesel traction this paper presents a model-based assessment of hydrogen-powered propulsion systems with an internal combustion engine or fuel cells as the prime mover combined with different energy storage system configurations based on lithium-ion batteries and/or double-layer capacitors. The analysis encompasses technology identification design modelling and assessment of alternative powertrains explicitly considering case-related constraints imposed by the infrastructure technical and operational requirements. Using a regional railway network in the Netherlands as a case we investigate the possibilities in converting a conventional benchmark vehicle and provide the railway undertaking and decision-makers with valuable input for planning of future rolling stock investments. The results indicate the highest fuel-saving potential for fuel cell-based hybrid propulsion systems with lithium-ion battery or a hybrid energy storage system that combines both energy storage system technologies. The two configurations also demonstrate the highest reduction of greenhouse gas emissions compared to the benchmark diesel-driven vehicle by about 25% for hydrogen produced by steam methane reforming and about 19% for hydrogen obtained from electrolysis of water with grey electricity.

Throughout the history of the mining petroleum process and nuclear industries continuous efforts have been made to develop and improve measures to prevent and mitigate accidental explosions. Over the coming decades energy systems are expected to undergo a transition towards sustainable use of conventional hydrocarbons and an increasing share of renewable energy sources in the global energy mix. The variable and intermittent supply of energy from solar and wind points to energy systems based on hydrogen or hydrogen-based fuels as the primary energy carriers. However the safety-related properties of hydrogen imply that it is not straightforward to achieve and document the same level of safety for hydrogen systems compared to similar systems based on established fuels such as petrol diesel and natural gas. Compared to the conventional fuels hydrogen-air mixtures have lower ignition energy higher combustion reactivity and a propensity to undergo deflagration-to-detonation-transition (DDT) under certain conditions. To achieve an acceptable level of safety it is essential to develop effective measures for mitigating the consequences of hydrogen explosions in systems with certain degree of congestion and confinement. Extensive research over the last decade have demonstrated that chemical inhibition or partial suppression can be used for mitigating the consequences of vapour cloud explosions (VCEs) in congested process plants. Total and cooperation partners have demonstrated that solid flame inhibitors injected into flammable hydrocarbon-air clouds represent an effective means of mitigating the consequences of VCEs involving hydrocarbons. For hydrogen-air explosions these same chemicals inhibitors have not proved effective. It is however well-known that hydrocarbons can affect the burning velocity of hydrogen-air mixtures greatly. This paper gives an overview over previous work on chemical inhibitors. In addition experiments in a 20-litre vessel have been performed to investigate the effect of combinations of hydrocarbons and alkali salts on hydrogen/air mixtures.

As part of the United Nations Global Technical Regulation No. 13 (UN GTR #13 [1]) vehicle fire safety is validated using a localized and engulfing fire test methodology and currently updates are being considered in the on-going Phase 2 development stage. The GTR#13 fire test is designed to verify the performance of a hydrogen storage system of preventing rupture when exposed to service-terminating condition of fire situation. The test is conducted in two stages – localized flame exposure at a location most challenging for thermally-activated pressure relief device(s) (TPRDs) to respond for 10 min. followed by engulfing fire exposure until the system vents and the pressure falls to less than 1 MPa or until “time out” (30min. for light-duty vehicle containers and 60 min. for heavy-duty vehicle containers). The rationale behind this two-stage fire test is to ensure that even when fire sizes are small and TPRDs are not responding the containers have fire resistance to withstand or fire sensitivity to respond to a localized fire to avoid system rupture. In this study appropriate fire sizes for localized and engulfing fire tests in GTR#13 are evaluated by considering actual fire conditions in a hydrogen-powered electric city bus. Quantitative risk analysis is conducted to develop various fire accident scenarios including regular bus fire battery fire and hydrogen leak fire. Frequency and severity analyses are performed to determine the minimum fire size required in GTR#13 fire test to ensure hydrogen storage tank safety in hydrogen-powered electric city buses.

For the successful deployment of the Heavy Duty (HD) hydrogen vehicles an associated infrastructure in particular hydrogen refueling stations (HRS) should be reliable compliant with regulations and optimized to reduce the related costs. FCH JU project PRHYDE aims to develop a sophisticated protocol dedicated to HD applications. The target of the project is to develop protocol and recommendations for an efficient refueling of 350 500 and 700 bar HD tanks of types III and IV. This protocol is based on modeling results as well as experimental data. Different partners of the PRHYDE European project are closely working together on this target. However modeling approaches and corresponding tools must first be compared and validated to ensure the high level of reliability for the modeling results. The current paper presents the benchmark performed in the frame of the project by Air Liquide Engie Wenger Engineering and NREL. The different models used were compared and calibrated to the configurations proposed by the PRHYDE project. In addition several scenarios were investigated to explore different cases with high ambient temperatures.

The present work investigates Power-to-Gas (PtG) options for variable Renewable Electricity storage into hydrogen through low temperature (alkaline and PEM) and high-temperature (SOEC) water electrolysis technologies. The study provides the assessment of the cost of the final product when hydrogen is employed for mobility (on-site refueling stations) electricity generation (by fuel cells in Power-to-Power systems) and grid injection in the natural gas network. Costs estimations are performed for 2013-2030 scenarios. A case study on the impact of variable Renewable Electricity storage by hydrogen generation on the Italian electricity and mobility sectors is presented.

This paper compares the relative cost of long-distance large-scale energy transmission by electricity and by gaseous and liquid carriers (e-fuels). The results indicate that the cost of electrical transmission per delivered MWh can be up to eight times higher than for hydrogen pipelines about eleven times higher than for natural gas pipelines and twenty to fifty times higher than for liquid fuels pipelines. These differences generally hold for shorter distances as well. The higher cost of electrical transmission is primarily due to lower carrying capacity (MW per line) of electrical transmission lines compared to the energy carrying capacity of the pipelines for gaseous and liquid fuels. The differences in the cost of transmission are important but often unrecognized and should be considered as a significant cost component in the analysis of various renewable energy production distribution and utilization scenarios.

Hydrogen production using anion exchange membrane water electrolysis (AEMWE) offers hope to the energy crisis faced by humanity. AEM electrolysis can be coupled with intermittent and renewable energy sources as well as with the use of low-cost electrocatalysts and other low-cost stack components. In AEM water electrolysis one of the biggest advantages is the use of low-cost transition metal catalysts instead of traditional noble metal electrocatalysts. AEMWE is still in its infancy despite irregular research on catalysts and membranes. In order to generate commercially viable hydrogen AEM water electrolysis technology must be further developed including energy efficiency membrane stability stack feasibility robustness ion conductivity and cost reduction. An overview of studies that have been conducted on electrocatalysts membranes and ionomers used in the AEMWEs is here reported with the aim that AEMWE research may be made more practical by this review report by bridging technological gaps and providing practical research recommendations leading to the production of scalable hydrogen.

Functionalization of semiconductors by metallic nanoparticle is considered to be one of the most effective procedure to improve photocatalytic hydrogen production. Photodeposition is frequently used for functionalization but particle sizes and dispersions are still difficult to control. Here Pt functionalization is achieved in a one-pot synthesis. The as-prepared samples are compared to reference materials prepared by conventional photodeposition and our results confirm that small and well-dispersed nanoparticles with superior stability are obtained by one-pot synthesis. The enhanced stability is attributed to a limited leaching of Pt nanoparticles during illumination likely caused by the preferable interaction of small well dispersed Pt nanoparticles with the TiO₂ support material. In addition our results demonstrate that Na-residues are detrimental for the photocatalytic performance and washing in acidic solution is mandatory to effectively reduce the sodium contamination.