Publications

Methane pyrolysis produces hydrogen (H2) with solid carbon black as a co-product eliminating direct CO2 emissions and enabling a low-carbon supply when combined with renewable or low-carbon heat sources. In this study we propose a hybrid geothermal pyrolysis configuration in which an enhanced geothermal system (EGS) provides baseload preheating and isothermal holding while either electrical or solar–thermal input supplies the final temperature rise to the catalytic set-point. The work addresses four main objectives: (i) integrating field-scale geothermal operating envelopes to define heatintegration targets and duty splits; (ii) assessing scalability through high-pressure reactor design thermal management and carbon separation strategies that preserve co-product value; (iii) developing a techno-economic analysis (TEA) framework that lists CAPEX and OPEX incorporates carbon pricing and credits and evaluates dual-product economics for hydrogen and carbon black; and (iv) reorganizing state-of-the-art advances chronologically linking molten media demonstrations catalyst development and integration studies. The process synthesis shows that allocating geothermal heat to the largest heat-capacity streams (feed recycle and melt/salt hold) reduces electric top-up demand and stabilizes reactor operation thereby mitigating coking sintering and broad particle size distributions. Highpressure operation improves the hydrogen yield and equipment compactness but it also requires corrosion-resistant materials and careful thermal-stress management. The TEA indicates that the levelized cost of hydrogen is primarily influenced by two factors: (a) electric duty and the carbon intensity of power and (b) the achievable price and specifications of the carbon co-product. Secondary drivers include the methane price geothermal capacity factor and overall conversion and selectivity. Overall geothermal-assisted methane pyrolysis emerges as a practical pathway to turquoise hydrogen if the carbon quality is maintained and heat integration is optimized. The study offers design principles and reporting guidelines intended to accelerate pilot-scale deployment.

Aviation is under increasing pressure to reduce carbon emissions in conventional transports and support the growth of low-altitude operations such as long-endurance eVTOLs. Hybrid-electric propulsion addresses these challenges by integrating the high specific energy of fuels or hydrogen with the controllability and efficiency of electrified powertrains. At present the field of hybrid-electric aircraft is developing rapidly. To systematically study hybrid-electric propulsion control in aviation this review focuses on practical aspects of system development including propulsion architectures system- and component-level modeling approaches and energy management strategies. Key technologies in the future are examined with emphasis on aircraft power-demand prediction multi-timescale control and thermal integrated energy management. This review aims to serve as a reference for configuration design modeling and control simulation as well as energy management strategy design of hybrid-electric propulsion systems. Building on this reference role the review presents a coherent guidance scheme from architectures through modeling to energy-management control with a practical roadmap toward flight-ready deployment.

This paper examines the techno-economic feasibility of utilising salt caverns for large-scale hydrogen storage in Ireland leveraging wind energy and proton exchange membrane (PEM) electrolysers. The analysis focuses on optimising the integration of wind power with hydrogen production and storage addressing key challenges such as energy curtailment grid transmission constraints and renewable energy intermittency. Findings highlight significant economic considerations with a single hydrogen storage cavern requiring an initial investment of approximately €240 million where geological site preparation and compressor systems constitute the largest cost components. Annual operational expenses (OPEX) are estimated at €4.6 million largely due to compressor energy consumption and cooling requirements. The study emphasizes the critical impact of electrolyser scale on economic viability. Small-scale systems such as a 20 MW PEM electrolyser are economically unfeasible with a levelised cost of hydrogen (LCOH) of around €10/kg and filling times extending up to 2.5 years. However scaling up to a 200 MW PEM electrolyser dramatically improves cost efficiency lowering the LCOH to approximately €0.83/kg and reducing filling times to just 90 days. This research provides a comprehensive framework for hydrogen storage development offering key insights for policymakers and industry stakeholders to drive the renewable energy transition and enhance energy security through cost-effective and sustainable storage solutions.

The high efficiency light weight and reliability of hydrogen energy electrochemical equipment are among the future development directions. Membrane electrode assemblies (MEAs) and electrolyzers as key components have structures and strengths that determine the efficiency of their power generation and the hydrogen production efficiency of electrolyzers. This article summarizes the evolution of membrane electrode and electrolyzer structures and their power and efficiency in recent years highlighting the significant role of integrated structures in promoting proton transport and enhancing performance. Finally it proposes the development direction of integrating electrolyte and electrode manufacturing using phase-change methods.

Accurately predicting hydrogen adsorption behavior is essential to developing efficient materials with storage capacities approaching those of liquid hydrogen and surpassing the performance of conventional compressed gas storage systems. Grand canonical Monte Carlo (GCMC) simulations accurately predict adsorption isotherms but are computationally expensive limiting large-scale material screening. We employ GPU-accelerated threedimensional classical density functional theory (DFT) based on the SAFT-VRQ Mie equation of state with a first-order Feynman–Hibbs correction to model hydrogen adsorption in [Zn(bdc)(ted)0.5] MOF-5 CuBTC and ZIF-8 at 30 K 50 K 77 K and 298 K. Our approach generates adsorption isotherms in seconds compared to hours for GCMC simulations with quantum corrections proving crucial for accurate low-temperature predictions. The results show good agreement with GCMC simulations and available experiments demonstrating classical DFT as a powerful tool for high-throughput material screening and optimizing hydrogen storage applications.

Environmental pollution caused by shipping has always received great attention from the international community. Currently due to the difficulty of fully electrifying medium- and large-scale ships the hybrid energy ship power system (HESPS) will be the main type in the future. Considering the economic and long-term energy efficiency of ships as well as the uncertainty of the output power of renewable energy units this paper proposes an improved design for an integrated power system for large cruise ships combining renewable energy and a hybrid energy storage system. An energy management strategy (EMS) based on time-gradient control and considering load dynamic response as well as an energy storage power allocation method that considers the characteristics of energy storage devices is designed. A bi-level power capacity optimization model grounded in comprehensive scenario planning and aiming to optimize maximum return on equity is constructed and resolved by utilizing an improved particle swarm optimization algorithm integrated with dynamic programming. Based on a large-scale cruise ship the aforementioned method was investigated and compared to the conventional planning approach. It demonstrates that the implementation of this optimization method can significantly decrease costs enhance revenue and increase the return on equity from 5.15% to 8.66%.

This study examined the effects of adding hydrogen to flammable liquid fuel droplets on emissions. It was found that an optimal mixing ratio with hydrogen can reduce the amount of NO in the reaction zone which is the area where the primary combustion reactions occur. N-pentane is burnt in air enriched with different amounts of hydrogen and the effects of the amount of hydrogen in the air on the combustion and emission parameters are investigated numerically. The combustion is modelled with the PDF/mixture fraction and standard twoequation turbulence models and thermal NO models are used for this modelling. The determination of the optimum H2 blending ratio is evaluated after the estimation results. It is evident that the addition of H2 led to an increase in spray flame temperatures. As a result the addition of H2 increases the combustion performance of n-pentane. The emissions evaluation results show that a blending ratio of 20% H2 reduces CO emissions at the combustion’s reaction zone and also results in a decrease in the mixture fraction. There is an increase in NO emissions due to the increase in spray flame temperatures. Combustion under air conditions containing 20% H2 by volume resulted in the highest temperature levels reaching 2130 K while the reduced NO levels decreased to approximately 11.3%. The thermal NO model when combined with the combustion model provides a sufficient level of agreement with the experimental data.

Today hydrogen is already widely regarded as up-and-coming source of energy. It is essential to meet energy needs while reducing environmental pollution since it has a high energy capacity and does not emit carbon oxide when burned. However for the widespread application of hydrogen energy it is necessary to search new technical solutions for both its production and storage. A promising effective and cost-efficient method of hydrogen generation and storage can be the use of solid materials including nanomaterials in which chemical or physical adsorption of hydrogen occurs. Focusing on the recommendations of the DOE the search is underway for materials with high gravimetric capacity more than 6.5% wt% and in which sorption and release of hydrogen occurs at temperatures from −20 to +100 ◦C and normal pressure. This review aims to summarize research on hydrogen generation and storage using silicon nanostructures and silicon composites. Hydrogen generation has been observed in Si nanoparticles porous Si and Si nanowires. Regardless of their size and surface chemistry the silicon nanocrystals interact with water/alcohol solutions resulting in their complete oxidation the hydrolysis of water and the generation of hydrogen. In addition porous Si nanostructures exhibit a large internal specific surface area covered by SiHx bonds. A key advantage of porous Si nanostructures is their ability to release molecular hydrogen through the thermal decomposition of SiHx groups or in interaction with water/alkali. The review also covers simulations and theoretical modeling of H2 generation and storage in silicon nanostructures. Using hydrogen with fuel cells could replace Li-ion batteries in drones and mobile gadgets as more efficient. Finally some recent applications including the potential use of Si-based agents as hydrogen sources to address issues associated with new approaches for antioxidative therapy. Hydrogen acts as a powerful antioxidant specifically targeting harmful ROS such as hydroxyl radicals. Antioxidant therapy using hydrogen (often termed hydrogen medicine) has shown promise in alleviating the pathology of various diseases including brain ischemia–reperfusion injury Parkinson’s disease and hepatitis.

The effectiveness of shot peening in suppressing hydrogen embrittlement (HE) of the heat-treated steels with different strength levels 790 MPa (115 ksi) and 930 MPa (135 ksi) was comprehensively investigated. A plastically deformed layer on the surface facilitated an increased number of dislocations and refined grain morphology. This hindered hydrogen transportation as confirmed by the results of electrochemical permeation exhibiting a decrease in the effective diffusion coefficient up to 47 %. The trapping behaviour of the steels scrutinized through Thermal Desorption Spectroscopy (TDS) proposed that dislocations are primary traps. Along with this residual compressive stresses (RCS) were introduced into the materials reaching a maximum of − 650 MPa and a depth of 250 μm. This prevented fracture of the steels under constant load in a plastic regime (1.05xYS) and 120 bar H2 environment. Slow Strain Rate Tensile (SSRT) tests indicated superior mechanical properties of the shot-peened steels under electrochemical charging reducing HE susceptibility by 15 %. Fracture morphology confirmed the protective nature of the plastically deformed layer highlighting a higher ductility of the fracture. RCS has been indicated as a determining factor in suppressing HE by shot peening regardless of the strength level of the steel.

As highlighted by the recent roadmaps from the European Union and the United States water electrolysis is the most valuable high-intensity technology for producing green hydrogen. Currently two commercial low-temperature water electrolyzer technologies exist: alkaline water electrolyzer (A-WE) and proton-exchange membrane water electrolyzer (PEM-WE). However both have major drawbacks. A-WE shows low productivity and efficiency while PEM-WE uses a significant amount of critical raw materials. Lately the use of anion-exchange membrane water electrolyzers (AEM-WE) has been proposed to overcome the limitations of the current commercial systems. AEM-WE could become the cornerstone to achieve an intense safe and resilient green hydrogen production to fulfill the hydrogen targets to achieve the 2050 decarbonization goals. Here the status of AEM-WE development is discussed with a focus on the most critical aspects for research and highlighting the potential routes for overcoming the remaining issues. The Review closes with the future perspective on the AEM-WE research indicating the targets to be achieved.