Canada

This study explores the potential of renewable seafood shell waste for sustainable energy conversion and longterm storage particularly for isolated communities. Despite its rich chitin and protein composition seafood shell waste is often neglected. The research evaluates and compares three advanced gasification technologies: biomass gasification plasma gasification and chemical looping to convert seafood shell waste into syngas and H2. The study uses validated Aspen Plus models to optimize feedstock blending ratios and operational parameters. Results show that feedstocks high in lobster and shrimp shells yield higher H2 outputs and improved syngas quality compared to clam-dominated blends. For instance biomass gasification at 1200 ◦C yielded approximately 500 kg/h of H2 from pure lobster or shrimp feeds while plasma gasification at 4500 ◦C achieved yields near 730 kg/ h. Plasma gasification when integrated with fuel cell conversion and heat recovery systems can generate over 10000 kWh during a 6-hour peak period enough to power over 1100 single-detached homes. Its levelized cost of hydrogen (LCOH) varies from $5.72-$8.37/kg H2 making it less expensive than chemical looping and biomass gasification. Plasma gasification also has the lowest global warming potential (GWP) at 6 kg CO2e/kg H2. Combining plasma gasification with carbon capture and storage may reduce GWP to 0.3 kg CO2e/kg H2 and can be further explored. These findings underscore the technical and economic viability of converting seafood shell renewable waste into H2 advancing sustainable energy transitions and supporting net-zero goals.

Ternary I-III-VI quantum dots (QDs) have recently received wide attention in solar energy conversion technologies because of their non-toxicity tunable band gap and composition-dependant optical properties. However their complex non-stoichiometry induces high density of surface traps/defects which significantly affects solar energy conversion efficiencies and long-term stability. This work presents an in-situ growth passivation approach to encapsulate ternary Cu:ZnInSe with ZnSeS alloyed shell (CZISe/ZSeS QDs) as light harvesters for solar-driven photoelectrochemical (PEC) hydrogen (H2) production. The engineered CZISe/ZSeS QDs coupled with TiO2- MWCNTs hybrid photoanode exhibit a high photocurrent density of 13.15 mA/cm2 at 0.8 V vs RHE under 1 sun illumination which is 20.5 % higher than bare CZISe QDs/TiO2 photoanode based device. In addition we observed a 48 % enhancement in the long-term stability with ~88 % current retained after 6000 s. These results indicate that the effective shell passivation has mitigated the surface traps/defects leading to suppressed charge recombination and improved charge transfer efficiency as confirmed by optoelectronic carrier dynamics measurements and theoretical simulations. The findings hold great promise on improving the performance of ternary/multinary eco-friendly colloidal QDs by surface engineering for effective utilization in solar energy conversion technologies.

Hydrogen production via water splitting is a crucial strategy for addressing the global energy crisis and promoting sustainable energy solutions. This review systematically examines water-splitting mechanisms with a focus on photocatalytic and electrochemical methods. It provides in-depth discussions on charge transfer reaction kinetics and key processes such as the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). Various electrode synthesis techniques including hydrothermal methods chemical vapor deposition (CVD) pulsed laser deposition (PLD) and radio frequency sputtering (RF) are reviewed for their advantages and limitations. The role of carbon-based materials such as graphene biochar and graphitic carbon nitride (g-C3N4) in photocatalytic and photoelectrochemical (PEC) water splitting is also highlighted. Their exceptional conductivity tunable band structures and surface functionalities contribute to efficient charge separation and enhanced light absorption. Further advancements in heterojunctions doped systems and hybrid composites are explored for their ability to improve photocatalytic and PEC performance by minimizing charge recombination optimizing electronic structures and increasing active sites for hydrogen and oxygen evolution reactions. Key challenges including material stability cost scalability and solar spectrum utilization are critically analyzed along with emerging strategies such as novel synthesis approaches and sustainable material development. By integrating water splitting mechanisms electrode synthesis techniques and advancements in carbon-based materials this review provides a comprehensive perspective on sustainable hydrogen production bridging previously isolated research domains.

Underground hydrogen storage (UHS) in basaltic rocks offers a scalable solution for large-scale sustainable energy needs yet its efficiency is limited by poorly constrained pore-scale hysteresis during cyclic hydrogenbrine flow. While basaltic rocks have been extensively studied for carbon sequestration and critical mineral extraction the pore-scale physics governing cyclic hydrogen-brine interactions particularly the roles of snap-off wettability and hysteresis remain inadequately understood. This knowledge gap hinders the development of predictive models and optimization strategies for UHS performance. This study presents a pore-scale investigations of cyclic hydrogen-brine flow in basaltic formations combining micro-computed tomography imaging with pore network modelling. A systematic workflow is employed to evaluate the effects of repeated drainage-imbibition cycles on multiphase flow properties under varying wetting regimes with emphasis on hysteresis evolution and its influence on recoverable hydrogen. Model validation is achieved through a novel benchmarking approach that incorporates synthetic fractures and morphological scaling enabling calibration against experimental capillary pressure and relative permeability. Results show that hydrogen trapping is primarily governed by snap-off and pore-body isolation particularly within large angular pores exhibiting high aspect ratios and limited connectivity. Strong hysteresis is observed between drainage and imbibition with hydrogen saturations averaging 85% predominantly in larger pore spaces compared to a residual saturation of 61% following imbibition. Repeated cycling leads to a gradual increase in residual saturation which eventually stabilizes indicating the onset of a hysteresis equilibrium state. Wettability emerges as a critical second-order control on displacement dynamics. Shifting from strongly to weakly water-wet conditions reduces capillary entry pressures enhances brine re-invasion and increases hydrogen recovery efficiency by ∼6%. These findings offer mechanistic insights into capillary trapping and wettability effects providing a framework for optimizing UHS reactive and abundant yet underutilized basalt formations and supporting ongoing global decarbonization efforts through reliable subsurface hydrogen storage.

This study presents a holistic technoeconomic analysis of solar photovoltaic-based green hydrogen production facilities assessing hydrogen output potential and cost structures under various facility configurations. Four system cases are defined based on the inclusion of new photovoltaic (PV) panels and hydrogen storage (HS) subsystems considering Southern Ontario solar data and a 30-year operational lifespan. Through a system level modeling we incorporate the initial costs of sub-systems (PV panels power conditioning devices electrolyser battery pack and hydrogen storage) operating and maintenance expenses and replacement costs to determine the levelized cost of hydrogen (LCOH). The results of this study indicate that including hydrogen storage significantly impacts optimal electrolyser sizing creating a production bottleneck around 400 kW for a 1 MWp PV system (yielding approximately 590 tons H2 over a period of 30 years) whereas systems without storage achieve higher yields (about 1080 tons of H2) with larger electrolysers (approximately 620 kW). The lifetime cost analysis reveals that operating and maintenance cost constitutes the dominant expenditure (68–76 %). Including hydrogen storage increases the minimum LCOH and sharply penalizes electrolyser oversizing relative to storage capacity. For a 1 MWp base system minimum LCOH ranged from approximately $3.50/kg (existing PV no HS) to $6/kg (existing PV with HS) $11–12/kg (new PV no HS) and $22–25/kg (new PV with HS). Leveraging existing PV infrastructure drastically reduces LCOH. Furthermore significant economies of scale are observed with increasing PV facility capacity potentially lowering LCOH below $2/kg at the 100 MWp scale. The study therefore underscores that there is a critical interplay between system configuration component sizing operating and maintenance management and facility scale in determining the economic viability of solar hydrogen production.

The present work aims to develop a uniquely designed experimental test rig for hydrogen (H2) production from hydrogen sulfide (H2S) and perform performance tests. The experimental activity focuses on the FeCl3 hybrid process for H2S cracking followed by H2S absorption sulfur purification and electrolysis for efficient H2 production. Hydrogen production is studied using KOH and FeCl3 electrolytes under varying temperatures between 20-80 ◦C. An electrochemical impedance spectroscopy (EIS) is employed to characterize the electrochemical cell under potentiostatic (0.5-2.0 V) and galvanostatic (0-0.5 mA) modes to analyze the system’s electrochemical response. The study results showed that hydrogen production increased by over 426 % from 20 ◦C to 80 ◦C. EIS analysis under potentiostatic mode showed Nyquist semicircle diameter reduced as the applied voltage increased from 0.5 V to 1.5 V and phase angle shifted from -5.59◦ to -1.27◦ confirming enhanced conductivity. Under galvanostatic mode the impedance dropped from ~25 Ω to ~21 Ω as current increased demonstrating improved kinetics for efficient H2 production.

Long-term reliability and accuracy of pressure valves are critical for hydrogen infrastructure and applications particularly in hydrogen-powered vehicles exposed to extreme weather conditions like cold winters and hot summers. This study evaluates such valves using the Endurance Test specified in European Commission Regulation (EU) No 406/2010 fulfilling Regulation (EC) No 79/2009 requirements for hydrogen vehicle type approval. A long short-term memory (LSTM) network accelerates valve development and validation by simulating endurance tests. The LSTM model with three inputs and one output predicts valve outlet pressure responses using experimental data collected at 25 ◦C 85 ◦C and − 40 ◦C simulating a 20-year lifecycle of 75000 cycles. At 25 ◦C the model achieves optimal performance with 40000 training cycles and an R2 of 0.969 with R2 values exceeding 0.960 across all temperatures. This efficient robust approach accelerates testing enabling realtime diagnostics and advancing hydrogen technologies for a sustainable future.

This Review provides an overview of the emerging concepts of catalystsmembranes and membrane electrode assemblies (MEAs) for water electrolyzers with anion-exchange membranes (AEMs) also known as zero-gap alkaline water electrolyzers. Much ofthe recent progress is due to improvements in materials chemistry MEA designs andoptimized operation conditions. Research on anion-exchange polymers (AEPs) has focusedon the cationic head/backbone/side-chain structures and key properties such as ionicconductivity and alkaline stability. Several approaches such as cross-linking microphase andorganic/inorganic composites have been proposed to improve the anion-exchangeperformance and the chemical and mechanical stability of AEMs. Numerous AEMs nowexceed values of 0.1 S/cm (at 60−80 °C) although the stability specifically at temperaturesexceeding 60 °C needs further enhancement. The oxygen evolution reaction (OER) is still alimiting factor. An analysis of thin-layer OER data suggests that NiFe-type catalysts have thehighest activity. There is debate on the active-site mechanism of the NiFe catalysts and their long-term stability needs to beunderstood. Addition of Co to NiFe increases the conductivity of these catalysts. The same analysis for the hydrogen evolutionreaction (HER) shows carbon-supported Pt to be dominating although PtNi alloys and clusters of Ni(OH) 2 on Pt show competitiveactivities. Recent advances in forming and embedding well-dispersed Ru nanoparticles on functionalized high-surface-area carbonsupports show promising HER activities. However the stability of these catalysts under actual AEMWE operating conditions needsto be proven. The field is advancing rapidly but could benefit through the adaptation of new in situ techniques standardizedevaluation protocols for AEMWE conditions and innovative catalyst-structure designs. Nevertheless single AEM water electrolyzercells have been operated for several thousand hours at temperatures and current densities as high as 60 °C and 1 A/cm 2 respectively.

Electrochemical energy conversion systems are recognized as sustainable options for clean power generation. In conjunction with this the current hydrogen storage methods often suffer from limited storage density stability or high cost which motivate the search for alternative fuels with improved performance. This study is designed to investigate ammonium formate as an effective hydrogen storage medium and an efficient electrochemical fuel in electrochemical energy conversion systems. In order to perform the experimental tests stainless steel-stainless steel and aluminum-stainless steel electrode pairs are selected and examined under varying concentrations of potassium hydroxide sodium chloride and hydrogen peroxide at 80 ◦C and the system responses are then evaluated through voltage–time monitoring and polarization curve analysis. The aluminum-stainless steel configuration achieves the highest performance under 0.1 M potassium hydroxide and 10 % hydrogen peroxide reaching the voltages near ~ 900 mV and current densities of ~ 340 mA cm− 2 ; and the sodium chloride systems produce up to ~ 820 mV and ~ 310 mA cm− 2 while higher additive levels result in decreasing the voltages below 500 mV due to losses and side reactions. These findings confirm that moderate additive concentrations and optimized electrode pairing significantly enhance efficiency positioning ammonium formate as a low-cost energy-dense fuel suitable for decentralized and portable applications.

Underground hydrogen storage is critical for supporting the transition to renewable energy systems addressing the intermittent nature of solar and wind power. Despite its promise as a carbon-neutral energy carrier there remains limited understanding of the geomechanical behavior of subsurface reservoirs under hydrogen storage conditions. This knowledge gap is particularly significant for fast-cycling operations which have yet to be implemented on a large scale. This review evaluates current knowledge on the geomechanics of underground hydrogen storage focusing on risks and challenges in geological formations such as salt caverns depleted hydrocarbon reservoirs saline aquifers and lined rock caverns. Laboratory experiments field studies and numerical simulations are synthesized to examine cyclic pressurization induced seismicity thermal stresses and hydrogen-rock interactions. Notable challenges include degradation of rock properties fault reactivation micro-seismic activity in porous reservoirs and mineral dissolution/precipitation caused by hydrogen exposure. While salt caverns are effective for low-frequency hydrogen storage their behavior under fast-cyclic loading requires further investigation. Similarly the mechanical evolution of porous and fractured reservoirs remains poorly understood. Key findings highlight the need for comprehensive geomechanical studies to mitigate risks and enhance hydrogen storage feasibility. Research priorities include quantifying cyclic loading effects on rock integrity understanding hydrogen-rock chemical interactions and refining operational strategies. Addressing these uncertainties is essential for enabling large-scale hydrogen integration into global energy systems and advancing sustainable energy solutions. This work systematically focuses on the geomechanical implications of hydrogen injection into subsurface formations offering a critical evaluation of current studies and proposing a unified research agenda.