Search

The production of solar hydrogen presents a compelling opportunity to harness solar energy, playing a crucial role in addressing climate change and reducing reliance on fossil fuels. The progress of the hydrogen economy largely depends on establishing hydrogen production as a key foundational element. Moreover, selecting appropriate materials to support the main catalyst is vital for enhancing hydrogen production. This article furnishes a simple, affordable approach to existing water-splitting technologies that harness solar energy as the primary source for hydrogen production. To achieve this, the impact of GO content on ZnO nanoparticles/GO compositions' photoelectrochemical efficiency is studied. While all the presented samples show sensitivity to light, the sample with 0.35% GO performs the best, demonstrating the highest photocurrent density, the lowest rate of electron-hole recombination, and the greatest photoelectrochemical efficiency. • The PEC behavior of ZnO/GO nano composite was studied with varying GO amount. • Efficient separation of e & h decreases recombination and charge transfer resistance. • The 0.35-%G sample shows the most enhanced PEC and best photo stability properties. • The 0.35-%G sample has the narrowest band-gap and the lowest-intensity PL spectrum. • The 0.35%G sample provides the most optimal conditions for water splitting. [ABSTRACT FROM AUTHOR]

The hydrogen economy faces significant challenges that cannot be addressed by market forces alone. High production costs, distribution logistics, and expensive utilization technologies hinder hydrogen's competitiveness. Additionally, economic and political interests that favor fossil fuels, the preservation of ruling elites, and colonial legacies, combined with media biases against hydrogen, further obstruct progress. This is evident in the backward-looking developments in Australia. Increased public awareness and support are crucial to drive government intervention, including subsidies and infrastructure investment, to overcome these barriers and facilitate hydrogen's integration into the global energy market. [ABSTRACT FROM AUTHOR]

The quest for cost effective but active electrocatalysts for water oxidation is at the forefront of research towards hydrogen economy. In this regard, bamboo as biomass derived N-doped cellulosic carbon has shown potential electrocatalytic performance towards water oxidation. The impregnation of optimum metallic Fe boosts the performance further, achieving an over potential value of 238 mV at a benchmark current density of 10 mA cm-2. Owing to its promising OER performances in alkaline freshwater, the electrocatalyst was further explored in alkaline saline water and alkaline real seawater, exhibiting overpotentials of 272 mV and 280 mV, respectively, to reach 10 mA cm-2 current density. Most importantly, the protective graphitic multilayer surrounding the metallic Fe allowed the electrocatalyst to demonstrate excellent durability over 30 h even at a high current density in alkaline real seawater electrolyte. [ABSTRACT FROM AUTHOR]

The urgent need for decarbonization drives the exploration of clean energy sources and carbon-free fuels, primarily with hydrogen as an emerging solution. This short communication article aims to provide a unique perspective on how to expedite transition to the hydrogen economy and make a quicker route to sectoral hydrogen-based solutions by deploying ammonia. The primary goal is, in this regard, to utilize green hydrogen as a clean feedstock and directly switch to synthesise ammonia for using it in almost all sectors directly without making infrastructural changes for hydrogen storage, transportation and distribution. This is due to the fact that the ammonia ecosystem already exists, but depending essentially on unclean hydrogen where fossil fuels are deployed to produce it. So, using the existing ammonia ecosystem with clean hydrogen production should be a target to overcome numerous challenges, especially requiring more investments and infrastructural changes. Furthermore, clean ammonia is potentially used as a fuel, an energy carrier, a working fluid, a refrigerant, and a commodity for various sectors, including industrial and agricultural. • Ammonia is a carbon-free fuel and suitable for use in various sectors. • Ammonia serves as a hydrogen carrier and helps for a quicker transition to a hydrogen economy. • Existing ammonia infrastructure is a big advantage for hydrogen economy. • Green hydrogen is essential for clean ammonia. [ABSTRACT FROM AUTHOR]

With the growing hydrogen economy, hydrogen is expected to play a significant part in the decarbonization of the world's energy supply. However, the use of hydrogen technologies necessitates the implementation of rigorous safety measures, such as the deployment of accurate hydrogen gas detection systems. Tin oxide (SnO 2) has been mainly studied to detect H 2 gas-sensing applications due to its significant chemical and thermal stability properties. The present review article aims to provide state-of-the-art knowledge of current developments of low-cost, eco-friendly hydrogen (H 2) gas sensors (HGS) based on functionalized tin oxide (SnO 2) nanostructures (SNS), offering greater efficiency and enhanced precision. The review article discuss the various technologies with their fundamental mechanism of hydrogen gas sensing. In this review article, the different fabrication routes of SNS coupled with modifications in their structural, surface, chemical, and electrical properties via metal doping, heterojunctions, ion implantation, light-assisted, carbon, and polymer-based hybrids are taken into account. Further, the study emphasized factors affecting sensing performance, recent technological advancements, and prevailing challenges in the area of SNS-inspired HGS. The review presents a few knowledge gaps, translated herewith as future perspectives and recommendations to instant possibility for future research and development. Hence, the present study could foster novel initiatives that may pave the way to revolutionizing SnO 2 -based HGS. [Display omitted] • The review proves a state-of-the-art of current advances in SnO 2 -based H 2 sensor. • Article includes a comprehensive study of different hydrogen sensing technologies. • Different fabrication routes of SnO 2 -based H 2 sensors are summarized. • SnO 2 modifications via heterojunction, ion & light irradiation, etc. are explained. • Recent technological advancements, and prevailing challenges are well defined. [ABSTRACT FROM AUTHOR]

Polymer electrolyte membrane fuel cells (PEMFCs) are an important enabler of the nascent hydrogen economy. However, due to the reliance on precious metal catalysts like platinum, reducing the cost and broad penetration of PEMFCs beyond vehicle application remains a challenge. In this respect, alternative non‐precious metal catalysts and other carbon‐based catalysts remain the holy grail toward advanced low‐cost PEMFC. This review summarizes recent progress along the development of non‐precious catalysts and their performance under PEMFC operation. Critical factors such as the activity, stability, and durability of non‐precious metal catalysts and their associated mechanisms including the paths leading to degradation are discussed. Ultimately, the review concludes by highlighting the impressive activity and potential of NPM catalysts and the areas of focus to enable the translation of non‐precious catalysts to commercially viable PEMFC systems. [ABSTRACT FROM AUTHOR]

Hydrogen energy heralded for its environmentally friendly, renewable, efficient, and cost‐effective attributes, stands poised as the primary alternative to fossil fuels in the future. Despite its great potential, the low volumetric density presents a formidable challenge in hydrogen storage. Addressing this challenge necessitates exploring effective storage techniques for a sustainable hydrogen economy. Solid‐state hydrogen storage in nanomaterials (physically or chemically) holds promise for achieving large‐scale hydrogen storage applications. Such approaches offer benefits, including safety, compactness, lightness, reversibility, and efficient generation of pure hydrogen fuel under mild conditions. This article presents solid‐state nanomaterials, specifically nanoporous carbons (activated carbon, carbon fibers), metal‐organic frameworks, covalently connected frameworks, nanoporous organic polymers, and nanoscale metal hydrides. Furthermore, new developments in hydrogen fuel cell technology for stationary and mobile applications have been demonstrated. The review outlines significant advancements thus far, identifies key barriers to practical implementation, and presents a perspective for future sustainable energy research. It concludes with recommendations to enhance hydrogen storage performance for cost‐effective and long‐lasting utilization. [ABSTRACT FROM AUTHOR]

Hydrogen‐driven energy is fascinating among the everlasting energy sources, particularly for stationary and onboard transportation applications. Efficient hydrogen storage presents a key challenge to accomplishing the sustainability goals of hydrogen economy. In this regard, solid‐state hydrogen storage in nanomaterials, either physically or chemically adsorbed, has been considered a safe path to establishing sustainability goals. Though metal hydrides have been extensively explored, they fail to comply with the set targets for practical utilization. Recently, MXenes, both in bare form and hybrid state with metal hydrides, have proven their flair in ascertaining the hydrides′ theoretical and experimental hydrogen storage capabilities far beyond the fancy materials and current state‐of‐the‐art technologies. This review encompasses the significant accomplishments achieved by MXenes (primarily in 2019–2024) for enhancing the hydrogen storage performance of various metal hydride materials such as MgH2, AlH3, Mg(BH4)2, LiBH4, alanates, and composite hydrides. It also discusses the bottlenecks of metal hydrides for hydrogen storage, the potential use of MXenes hybrids, and their challenges, such as reversibility, H2 losses, slow kinetics, and thermodynamic barriers. Finally, it concludes with a detailed roadmap and recommendations for mechanistic‐driven future studies propelling toward a breakthrough in solid material‐driven hydrogen storage using cost‐effective, efficient, and long‐lasting solutions. [ABSTRACT FROM AUTHOR]

In this work a novel mathematical programming formulation is presented for the simultaneous optimal design and operation of standalone, green hydrogen production systems. There is a pressing need to develop, test and commercialize technologies that can contribute in the medium term to our coordinated efforts to combat climate change. The system under study is inherently dynamic due to the stochastic and intermittent nature of meteorological data and there is a likelihood to overestimate its production capacity and economic performance. Failing to identify shortcoming in the design stage can result in expensive operational mistakes that will negatively affect the gathering race to build a massive new hydrogen economy. We present and demonstrate a systematic methodology that could be useful in decarbonizing our energy production systems by optimizing standalone, green hydrogen units and reducing the risk during their commercialization. • A methodology is developed to optimize standalone green hydrogen production systems • A detailed nonlinear model is proposed that captures design and operational details • A solution methodology is developed that ensures convergence [ABSTRACT FROM AUTHOR]

Growing expectations are being placed on green hydrogen-based steel for decarbonising the global steel industry. However, the scale of the expected demand is dispersed across numerous case studies, resulting in a fragmented picture. This study examines 28 existing scenarios to provide a cohesive view of future global demand. In the short term, the demand for green hydrogen-based steel is expected to be limited, constituting 2% of current total steel production by 2030. However, a transformation phase is expected around 2040, marked by accelerated growth. By 2050, global demand is projected to reach 660 Mt (with an interquartile range of 368–1000 Mt), equivalent to 35% (19%–53%) of current total steel production. To meet such growing demand, green hydrogen supply and electrolyser capacity will need to increase to more than 1000 times current levels by 2050. These trends highlight both short-term limitations and long-term potential. Decarbonisation efforts will therefore require immediate emission reductions with already scalable options, while simultaneously building the enabling infrastructure for green hydrogen-based steelmaking to ensure long-term impacts. [Display omitted] • Analysis of 28 scenarios provides an integrated view of global green steel demand. • Short-term demand is expected to be limited, with an estimate of ∼35 Mt by 2030. • Long-term prospects indicate significant growth, potentially reaching ∼660 Mt by 2050. • Significant scale-up of green hydrogen supply and electrolyser capacity is required. [ABSTRACT FROM AUTHOR]

The carbon-neutrality target set by the European Union for 2050 drives the increasing relevance of green hydrogen as key player in the energy transition. This work uses the JRC-EU-TIMES energy system model to assess opportunities and challenges for green hydrogen trade from North Africa to Europe, analysing to what extent it can support its decarbonization. An important novelty is addressing uncertainty regarding hydrogen economy development. Alternative scenarios are built considering volumes available for import, production costs and transport options, affecting hydrogen cost-effectiveness. Both pipelines and ships are modelled assuming favourable market conditions and pessimistic ones. From 2040 on, all available North African hydrogen is imported regardless of its costs. In Europe this imported hydrogen is mainly converted into synfuels and heat. The study aims to support policymakers to implement effective strategies, focusing on the crucial role of green hydrogen in the decarbonization process, if new competitive cooperations are developed. • The role of green hydrogen in long-term decarbonization is affected by uncertainty. • The JRC-EU-TIMES model is exploited to study alternative pathways for trade. • Different importable volumes, production costs and transport options are modelled. • From 2040 on, EU + import all the North African hydrogen, regardless of its cost. • EU + countries are differently sensitive to uncertainty factors on hydrogen import. [ABSTRACT FROM AUTHOR]

Hydrogen is a promising solution for the decarbonisation of several hard-to-abate end uses, which are mainly in the industrial and transport sectors. The development of an extensive hydrogen delivery infrastructure is essential to effectively activate and deploy a hydrogen economy, connecting production, storage, and demand. This work adopts a mixed-integer linear programming model to study the cost-optimal design of a future hydrogen infrastructure in presence of cross-sectoral hydrogen uses, taking into account spatial and temporal variations, multiple production technologies, and optimised multi-mode transport and storage. The model is applied to a case study in the region of Sicily in Italy, aiming to assess the infrastructural needs to supply the regional demand from transport and industrial sectors and to transfer hydrogen imported from North Africa towards Europe, thus accounting for the region's role as transit point. The analysis integrates multiple production technologies (electrolysis supplied by wind and solar energy, steam reforming with carbon capture) and transport options (compressed hydrogen trucks, liquid hydrogen trucks, pipelines). Results show that the average cost of hydrogen delivered to demand points decreases from 3.75 €/kg H2 to 3.49 €/kg H2 when shifting from mobility-only to cross-sectoral end uses, indicating that the integrated supply chain exploits more efficiently the infrastructural investments. Although pipeline transport emerges as the dominant modality, delivery via compressed hydrogen trucks and liquid hydrogen trucks remains relevant even in scenarios characterised by large hydrogen flows as resulting from cross-sectoral demand, demonstrating that the system competitiveness is maximised through multi-mode integration. [Display omitted] • A hydrogen supply chain model is extended to study delivery to multi-sector demand. • Industrial uses impose flat profiles with large quantities, while mobility demand is more variable. • The cost-optimal hydrogen infrastructure relies on combined transport modes. • Cross-sectoral deployment of hydrogen has positive impact on the cost of infrastructure. [ABSTRACT FROM AUTHOR]

The impacts of climate change are real and in many parts of the world testify to its harsh reality, including rampant extreme weather events, droughts, heat, wildfires, and flooding which have recorded in places which have not experienced them in recent memory. In the quest to avert such events, there is a growing awareness and demand for sustainable processes and operations. Today, sustainability encompasses a balance between ecological footprint and human development index, taking into consideration economics, the green environment, safety, quality, ethics, diversity and inclusion (D&I), and communities. This article presents some steps that have been taken by Algeria to balance energetic autonomy and sustainable development, and a case study on green hydrogen production employing membrane processes. Algeria's objective to join the global fight against climate change is to develop its green hydrogen base. Given its resources, including available solar and wind power, seawater desalination plants, building capacity, and its favorable location, it is developing its green hydrogen economy to supply hydrogen, especially to Europe. This presents an opportunity for other developing nations, especially in Africa, to gain from this experience. [ABSTRACT FROM AUTHOR]

The development of efficient and cost-effective electrocatalysts is crucial for achieving a green hydrogen economy through electrocatalytic water splitting. Herein, we report an excellent catalyst, one-dimensional NiS2/NiS/Mn2O3 nanofibers prepared by electrospinning, which exhibits outstanding electrochemical performance in an alkaline solution. We explored effective strategies to construct one-dimensional nanostructures and composite oxides to promote the electrocatalytic performance of transition metal dichalcogenides. At a current density of 20 mA cm−2, it requires an overpotential of 333 mV for OER. Furthermore, NiS2/NiS/Mn2O3 nanofibers maintain good durability even after 1000 cycles. The long-term electrochemical stability test of the catalyst NiS2/NiS/Mn2O3 was implemented at 20 mA cm−2 for 12 h. The potential remained at 99.52%. Therefore, this study demonstrates that NiS2/NiS/Mn2O3 can serve as a viable green hydrogen production electrocatalyst. [ABSTRACT FROM AUTHOR]

Efficient hydrogen storage and transportation are crucial for the sustainable development of human society. Ammonia, with a hydrogen storage density of up to 17.6 wt%, is considered an ideal energy carrier for large-scale hydrogen storage and has great potential for development and application in the "hydrogen economy". However, achieving ammonia decomposition to hydrogen under mild conditions is challenging, and therefore, the development of suitable catalysts is essential. Metal oxide-based catalysts are commonly used in the industry. This paper presents a comprehensive review of single and composite metal oxide catalysts for ammonia decomposition catalysis. The focus is on analyzing the conformational relationships and interactions between metal oxide carriers and active metal sites. The aim is to develop new and efficient metal oxide-based catalysts for large-scale green ammonia decomposition. [ABSTRACT FROM AUTHOR]

Metal phosphides have been hailed as potential replacements for scarce noble metal catalysts in many aspects of the hydrogen economy from hydrogen evolution to selective hydrogenation reactions. But the need for dangerous and costly phosphorus precursors, limited support dispersion, and low stability of the metal phosphide surface toward oxidation substantially lower the appeal and performance of metal phosphides in catalysis. We show here that a 1‐step procedure that relies on safe and cheap precursors can furnish an air‐stable Ni2P/Al2O3 catalyst containing 3.2 nm nanoparticles. Ni2P/Al2O3 1‐step is kinetically competitive with the palladium‐based Lindlar catalyst in selective hydrogenation catalysis, and a loading corresponding to 4 ppm Ni was sufficient to convert 0.1 mol alkyne. The 1‐step synthetic procedure alters the surface ligand speciation of Ni2P/Al2O3, which protects the nanoparticle surface from oxidation, and ensures that 85 % of the initial catalytic activity was retained after the catalyst was stored under air for 1.5 years. Preparation of Ni2P on a variety of supports (silica, TiO2, SBA‐15, ZrO2, C and HAP) as well as Co2P/Al2O3, Co2P/TiO2 and bimetallic NiCoP/TiO2 demonstrates the generality with which supported metal phosphides can be accessed in a safe and straightforward fashion with small sizes and high dispersion. [ABSTRACT FROM AUTHOR]

The transition to a hydrogen-based economy presents a promising solution to the challenges posed by unsustainable energy systems and reliance on fossil fuels. This comprehensive review explores various hydrogen production methods, emphasizing their technological advancements, sustainability implications, and future prospects. Beginning with an overview of hydrogen's significance as a clean energy carrier, the review examines key production methods such as Steam Methane Reforming, Electrolysis (Proton Exchange Membrane, alkaline, solid oxide), Biomass Gasification, Photoelectrochemical Water Splitting, and Thermochemical Processes. Each method is scrutinized for its efficiency, environmental impact, and scalability, providing valuable insights into their roles in advancing the hydrogen economy. The review highlights the transformative potential of hydrogen production to replace fossil fuels due to its ability to store renewable energy long-term and its zero emissions. It also discusses potential technological advancements, including high-efficiency solid-state electrolysis and advanced catalysts for water splitting, highlighting avenues for innovation in hydrogen production. Additionally, policy recommendations aimed at promoting the hydrogen economy and fostering collaboration between academia, industry, and governments are elucidated. Through a detailed analysis of hydrogen production technologies and future prospects, this review contributes to shaping the trajectory of sustainable energy systems, advancing the adoption of hydrogen as a key energy vector, and underscoring the importance of alternative and sustainable energy sources. • Hydrogen economy addresses unsustainable energy challenges. • Review covers key hydrogen production methods and technologies. • Examines efficiency, environmental impact, scalability of each method. • Highlights advances in catalysts and solid-state electrolysis. • Recommends policies for renewable integration, innovation, and collaboration. [ABSTRACT FROM AUTHOR]

This study addresses the critical need for a comprehensive review of the legal and regulatory landscape for hydrogen energy in the US, motivated by its potential to enhance energy security, create a diverse energy mix, and mitigate climate change. The novelty lies in its thorough examination of fragmented hydrogen regulations across federal and state levels, highlighting issues such as lack of national law, regional overregulation, inconsistencies in subsidy support mechanisms, and underfunded long-term hydrogen initiatives, which have received limited academic attention. Non-technical updates, such as harmonized codes and standards, improved safety practices, a strong supply chain, and a skilled workforce, are also essential. The study emphasizes the need for more infrastructure investment and a systematic framework, as 60% of hydrogen production and consumption is on-site. This research contributes to the literature by emphasizing the need for a cohesive framework, substantial infrastructure investment, and collaboration among stakeholders to advance the hydrogen economy. [Display omitted] • Hydrogen laws, policies, regulations, and strategies in the U.S. are reviewed. • Hydrogen laws and regulations are spread across different codes of federal regulations. • Two levels of regulations exist in the U.S. • Various regulatory bodies oversee the hydrogen value chain. • The majority of US hydrogen strategies are now focusing on R&D and incentives. [ABSTRACT FROM AUTHOR]

This paper presents a thorough critical literature review aimed at understanding the challenges associated with freshwater supply associated with rapidly growing global hydrogen economies. The review has been prompted by the fact that the hydrogen production projected for 2030 will create at least an additional demand of 2.1 billion cubic meters for freshwater, which needs to be addressed to support sustainable development of emerging hydrogen economies. The key solutions explored by this study include seawater and wastewater treatment methods for large-scale freshwater generation, along with the newly introduced technique of direct seawater-fed electrolysis. Prior research indicates that desalination technologies, including reverse osmosis and membrane distillation, also offer promising avenues for large-scale freshwater production at costs comparable to other desalination techniques. Additionally, low-temperature desalination methods such as membrane distillation could play a significant role in freshwater production for electrolysis, underscoring the importance of exploring waste recovery opportunities within the system (e.g., fuel cell heat recovery). This review also identifies research gaps that need to be addressed to overcome freshwater supply challenges and enhance the sustainability and techno-economic viability of large-scale hydrogen energy systems. • The projected hydrogen demand by 2030 will create approximately 21 billion cubic meters of freshwater demand. • The target cost projections of ∼2–3 $/kg-H 2 have often neglected the cost of freshwater supply. • Seawater and wastewater resources can be utilised to support hydrogen production at large scales. • Direct seawater electrolysis and desalination technologies can support green hydrogen production. • Utilising fuel cells and electrolysers waste heat for desalination can reduce the energy cost of hydrogen production by ∼5%. [ABSTRACT FROM AUTHOR]

The production and utilization of hydrogen (H 2) as a clean energy source offer a promising solution towards achieving net-zero carbon emissions. Utilizing sandstone formations for geological hydrogen storage presents a viable option for the practical implementation of the hydrogen economy, offering both safe and large-scale containment capabilities. Accurate assessment of gas displacement behavior in porous media plays a critical role in understanding gas saturation, gas residual, and long-term storage duration. However, there are limited studies available on dynamic displacements for hydrogen storage applications. This study aims to enhance the understanding of gas flow behavior in sandstone rocks for different gas types and determine the role of capillary pressure and gas wettability during hydrogen storage. A series of gas core-flooding experiments are performed on a brine-saturated sandstone core sample using three different gases (CO 2 , CH 4, and H 2). X-ray scanning technique is applied to detect the gas saturation and gas residual after the core-flooding experiments. The results indicate that the average gas saturation ranges between 25 and 40%, with zero gas residual for all gases, suggesting that the gas residuals in this clean sandstone sample are unaffected by the gas type. Initially, the capillary pressure profile for the sample displayed low brine saturation at 200 psi, indicating very low capillary pressure in the sample due to the high permeability and large pore radius, despite the strong water-wetting behavior of the sample. Moreover, the obtained results indicate the high potential for gas recovery (especially for hydrogen during withdrawal cycles), and the high displacement efficiency in sandstone rocks. The reported low gas residual suggests that the wettability of the rock is not affected by gas injection, and it appears that the wettability and capillary pressure are not the controlling factors for gas storage in this sandstone sample. This observation suggests that the structural trapping mechanism is most likely to be the dominant trapping mechanism in this shallow high permeable sandstone rock. Also, the injection of cushion gases such as CO 2 and CH 4 indicated similar results to hydrogen injection, due to the low capillary pressure and high permeability in this sandstone sample. The findings of this study can greatly enhance the understanding of gas injection, displacement behavior, and gas residuals in sandstone rocks related to underground hydrogen storage. • The behavior of gas injection and dynamic displacements in sandstone reservoirs are investigated vis X-ray core-flooding. • CO 2 displayed an average gas saturation of 40%, while the average gas saturation for H 2 and CH 4 ranged between 25 and 30%. • The residual gas saturations in the sample were almost zero for all gases. • The rock wettability was not affected by gas injection. • Structural trapping mechanism appears to be the dominant trapping mechanism for shallow high-permeable sandstone rocks. [ABSTRACT FROM AUTHOR]

Hydrogen will play a key role in decarbonizing economies. Here, we quantify the costs and environmental impacts of possible large-scale hydrogen economies, using four prospective hydrogen demand scenarios for 2050 ranging from 111–614 megatonne H2 year−1. Our findings confirm that renewable (solar photovoltaic and wind) electrolytic hydrogen production generates at least 50–90% fewer greenhouse gas emissions than fossil-fuel-based counterparts without carbon capture and storage. However, electrolytic hydrogen production could still result in considerable environmental burdens, which requires reassessing the concept of green hydrogen. Our global analysis highlights a few salient points: (i) a mismatch between economical hydrogen production and hydrogen demand across continents seems likely; (ii) region-specific limitations are inevitable since possibly more than 60% of large hydrogen production potentials are concentrated in water-scarce regions; and (iii) upscaling electrolytic hydrogen production could be limited by renewable power generation and natural resource potentials. Future hydrogen economies need massive amounts of low-carbon hydrogen. Here, we show that mismatches between economic production and supply locations, water scarcity, and the need for renewable power and materials might limit large-scale hydrogen production. [ABSTRACT FROM AUTHOR]

The generation of solar H 2 emerges as a promising avenue for leveraging solar energy, contributing to mitigating climate change and restricting fossil fuel combustion. The advancement of the hydrogen economy significantly pivots on the production of hydrogen as a fundamental cornerstone. This article furnishes an overview of the available water-splitting technologies for harnessing solar energy as the primary source for hydrogen production, emphasizing the significant solar-to-hydrogen (STH) conversion efficiency. Photocatalytic water splitting, Photoelectrochemical water splitting, and Photovoltaic electrochemical water splitting have been thoroughly addressed over the past five-year period. A comprehensive assessment involves the evaluation and scrutiny of these solar technologies, acknowledging their commercial viability by analyzing key indicators like STH efficiency, robustness, economic likelihood, ecological sustainability, and other innovative attributes. [Display omitted] • Hydrogen economy is hailed as a pioneering element in sprouting a low-carbon future. • Solar hydrogen produced via water electrolysis is a reliable fossil fuel alternate. • Three core technologies delineate water splitting with distinct innovative features. • Elaborated on their advancements over the last five years extensively. • Each technology is methodically discussed highlighting their respective attributes. [ABSTRACT FROM AUTHOR]

South Africa is an energy-intensive developing country in Africa and ranked as the 1st and 14th emitter of greenhouse gas (GHG) in Africa and the world, respectively. The abundance and availability of coal in South Africa make it the mainstay primary source of energy contributing 56% of national total GHG emissions. This paper focused on the duo of energy generation and emission associated with coal processing and utilization in South Africa, and the urgent need to advance coal processing technologies marked by high carbon footprints in consonance with the sustainable development goals. Different gasification techniques and their performances have been compiled and discussed. The economic, environmental impact, energetic, and exergetic characteristics of existing hydrogen production technologies for renewable and non-renewable energy sources have been examined along with hydrogen production from plasma gasification of coal. Hydrogen production via coal or coal/biomass plasma gasification technology (nuclear-, wind-, PV solar-, and concentrated solar power-driven) in addition to carbon capture technology for transforming the captured CO 2 into value-added products appears to be the most viable option to considerably reduce emissions and meet the energy demand of South Africa. This proposed technology can be pivotal to achieving a low-carbon economy (medium-term) and transition to hydrogen economy (long-term) as championed by the global sustainable development agenda. Conclusively, hydrogen (stored in different forms e.g., liquid hydrogen, ammonia, and organic hydride) seems to find more applications (in the space industry, transport, energy storage, defense industry, etc.) than coal owing to its immediate use in distribution/demand centers and remote areas. • Coal is the primary energy source of South Africa and key driver of national CO 2 emissions. • Traditional coal gasification technologies are marked by high CO 2 emissions. • Coal plasma gasification technology is a viable option for low-carbon energy economy. • Hydrogen production via coal or coal/biomass plasma gasification technology leads to zero-carbon economy. • This immensely supports the drive towards attaining the sustainable development goals. [ABSTRACT FROM AUTHOR]

As Sweden takes its first steps towards a hydrogen-based economy, a strategic approach to infrastructure development for both storage and delivery becomes necessary. Although compressed hydrogen is currently the state-of-the-art, its low volumetric density and associated high capital costs pose challenges to widespread societal deployment of hydrogen. In order to avoid technological lock-in, alternatives storage technologies including chemical hydrides, e.g. methanol, ammonia, methane and LOHC, must also be explored. These alternatives offer higher hydrogen densities, safer handling, and compatibility with existing infrastructure. However, each hydride has unique chemical and physical properties, requires distinct feedstock and conversion processes, and interacts with the energy system in different ways, all of which influences their suitability for various applications. Therefore, a comprehensive evaluation of these alternative hydrogen storage technologies, as carried out in this article, is vital to allow for informed investment decisions and pave the way towards a successful and sustainable hydrogen economy. • Chemical hydrides have emerged as promising hydrogen storage alternatives. • Chemical hydrides facilitate cheaper global hydrogen trade. • Sweden's biogenic CO 2 emissions promote storage in methanol and methane. • Optimal storage choice depends on specific applications and their energy systems. • Chemical hydrides have high technological maturity. [ABSTRACT FROM AUTHOR]

Hydrogen is viewed as the future carbon–neutral fuel, yet hydrogen storage is a key issue for developing the hydrogen economy because current storage techniques are expensive and potentially unsafe due to pressures reaching up to 700 bar. As a consequence, research has recently designed advanced hydrogen sorbents, such as metal–organic frameworks, covalent organic frameworks, porous carbon-based adsorbents, zeolite, and advanced composites, for safer hydrogen storage. Here, we review hydrogen storage with a focus on hydrogen sources and production, advanced sorbents, and machine learning. Carbon-based sorbents include graphene, fullerene, carbon nanotubes and activated carbon. We observed that storage capacities reach up to 10 wt.% for metal–organic frameworks, 6 wt.% for covalent organic frameworks, and 3–5 wt.% for porous carbon-based adsorbents. High-entropy alloys and advanced composites exhibit improved stability and hydrogen uptake. Machine learning has allowed predicting efficient storage materials. [ABSTRACT FROM AUTHOR]

Hydrogen has gained enormous relevance due to its lower carbon footprint and its potential role in balancing energy supply and demand. It is being considered as a sustainable substitute for conventional fuels. The generation of hydrogen using renewable energy sources is still in development, with a significant challenge lying in the efficient and safe storage of hydrogen due to its low energy density. This challenge hinders the widespread adoption of hydrogen. Compression and liquefaction methods of storage face issues of losses that reduce their effectiveness. The technology for hydrogen storage has advanced significantly in the past few years, driven by recent enhancements in synthesizing carbonaceous materials with hydrogen storage capabilities. This article critically reviews novel carbonaceous materials for hydrogen storage, including biochar, activated carbon, carbon nanotubes, carbon nanocomposites, carbon aerogel, fullerenes, MXenes, graphite, graphene and its derivatives. Effective hydrogen adsorption using microporous materials, such as activated carbons, is crucial, sparking interest in economically viable options for hydrogen storage. Despite this, a significant amount of work still needs to be accomplished before the potential and advantages of the hydrogen economy can be fully realized and utilized by manufacturers and academics. [ABSTRACT FROM AUTHOR]

The forthcoming implementation of national policies towards hydrogen blending into the natural gas grid will affect the technical and economic parameters that must be taken into account in the design of building heating systems. This study evaluates the implications of using hydrogen-enriched natural gas (H2NG) blends in condensing boilers and Gas Adsorption Heat Pumps (GAHPs) in a residential building in Rome, Italy. The analysis considers several parameters, including non-renewable primary energy consumption, CO2 emissions, Levelized Cost of Heat (LCOH), and Carbon Abatement Cost (CAC). The results show that a 30% hydrogen blend achieves a primary energy consumption reduction of 12.05% and 11.19% in boilers and GAHPs, respectively. The presence of hydrogen in the mixture exerts a more pronounced influence on the reduction in fossil primary energy and CO2 emissions in condensing boilers, as it enhances combustion efficiency. The GAHP system turns out to be more cost-effective due to its higher efficiency. At current hydrogen costs, the LCOH of both technologies increases as the volume fraction of hydrogen increases. The forthcoming cost reduction in hydrogen will reduce the LCOH and the decarbonization cost for both technologies. At low hydrogen prices, the CAC for boilers is lower than for GAHPs; therefore, replacing boilers with other gas technologies rather than electric heat pumps increases the risk of creating stranded assets. In conclusion, blending hydrogen into the gas grid can be a useful policy to reduce emissions from the overall natural gas consumption during the process of end-use electrification, while stimulating the development of a hydrogen economy. [ABSTRACT FROM AUTHOR]

The adoption of green hydrogen economy is an indispensable necessity in the current global scenario of environment and energy security. In this endeavor, ammonia is poised to play a key vector of hydrogen to mitigate the challenges arising from transportation, storage and safety. Besides containing a high volumetric and gravimetric hydrogen density, NH3 decomposition into H2 for onsite utilization as a distributed energy source is devoid of greenhouse gases production. In this endeavor, significant technological advancements have been made for in situ production of H2 from NH3 decomposition and the use of NH3 in fuel cell devices to produce electricity. The ammonia decomposition methods to produce H2 mainly involve thermocatalytic, oxidative, electrocatalytic and photocatalytic, among which the catalyst assisted thermal cracking of NH3 has been widely investigated. The research progress in electrolysis of NH3 has been notable in the last couple of years and provides a low‐cost alternative to produce H2 at room temperature. In the area of device development, solid oxide fuel cells (SOFC) have witnessed rapid development in the performances and stability, as ammonia is completely decomposed into H2 and N2 at high operating temperature above ~700 °C. [ABSTRACT FROM AUTHOR]

Hydrogen storage materials play a pivotal role in the development of a sustainable hydrogen economy. However, the discovery and optimization of high-performance storage materials remain a significant challenge due to the complex interplay of structural, thermodynamic and kinetic factors. Computational materials science has emerged as a powerful tool to accelerate the design and development of novel hydrogen storage materials by providing atomic-level insights into the storage mechanisms and guiding experimental efforts. In this comprehensive review, we discuss the recent advances in crystal structure prediction and performance assessment of hydrogen storage materials from a computational perspective. We highlight the applications of state-of-the-art computational methods, including density functional theory (DFT), molecular dynamics (MD) simulations, and machine learning (ML) techniques, in screening, evaluating, and optimizing storage materials. Special emphasis is placed on the prediction of stable crystal structures, assessment of thermodynamic and kinetic properties, and high-throughput screening of material space. Furthermore, we discuss the importance of multiscale modeling approaches that bridge different length and time scales, providing a holistic understanding of the storage processes. The synergistic integration of computational and experimental studies is also highlighted, with a focus on experimental validation and collaborative material discovery. Finally, we present an outlook on the future directions of computationally driven materials design for hydrogen storage applications, discussing the challenges, opportunities, and strategies for accelerating the development of high-performance storage materials. This review aims to provide a comprehensive and up-to-date account of the field, stimulating further research efforts to leverage computational methods to unlock the full potential of hydrogen storage materials. [ABSTRACT FROM AUTHOR]

Recycling waste polyethylene terephthalate (PET) bottles into value-added ligand materials for synthesizing metal-organic frameworks (MOFs) derived catalysts is an eco-friendly and economically viable process. The waste PET bottles were readily broken down into 1,4-benzenedicarboxylic acid (BDC) ligands in a highly alkaline environment. Herein, we fabricated a Co@Cr(OH) 3 /ZrO 2 catalyst via the carbonization of PET-derived UiO-66 metal-organic frameworks for the catalytic dehydrogenation of formic acid at low temperatures. The as-prepared Co@Cr(OH) 3 /ZrO 2 catalyst provides a turnover frequency of 7685 h−1 for hydrogen generation (120 mL in 1.5 min) at ambient temperature. This is due to the uniform dispersion of the fine metal nanoparticle (NPs) (Co NPs, ∼3.75 nm) and the synergistic effect of the Co NPs and Cr(OH) 3 /ZrO 2 supports. In addition, the characterization results indicate that porous Zr-MOFs may effectively enclose tiny particles, which is favorable for enhanced dehydrogenation performance. In addition, the Co@Cr(OH) 3 /ZrO 2 catalysts demonstrated excellent stability against aggregation and were recyclable over seven cycles without any significant catalytic loss. Thus, this study provides a sustainable methodology for the development of MOF-derived, effective, and stable catalysts for formic acid dehydrogenation towards hydrogen production. [ABSTRACT FROM AUTHOR]

An essential part of addressing greenhouse gas emissions-related environmental issues is hydrogen energy. However, advances in technology are still needed for the industrial use of hydrogen, particularly in determining the most effective means of storage and transportation. As a result, the evolution, trends, updates, and research progress on hydrogen storage related topics were assessed in this bibliometric review, along with the difficulties posed by the application of various hydrogen storage technologies. Bibliometric analysis was performed using the R software's Biblioshiny package, and documents from 2013 to 2023 were chosen using the Scopus database using the PRISMA method. A total of 4456 documents were obtained within the period of study, with an annual growth rate of 21.7%. The study shows that themes such as dehydrogenation, hydrogenation, and hydrogen storage are well-developed themes in the area of the study. Emerging areas of study that have become areas of interest to researchers relative to hydrogen storage include themes such as metal hydrides and liquid hydrogen. Hydrogen evolution reactions, photocatalysis, oxygen evolution reactions, and electrocatalysts were found to be the actual themes of the field of study, i.e., niche themes. It is recommended that researchers focus more on liquid hydrogen storage and high-pressure gaseous systems and take the whole hydrogen energy utilization process into account. • This study employed the bibliometric and PRISMA method to review literature on hydrogen storage technologies. • A total of 4456 documents were reviewed between the period of 2013–2023. • Detailed review of various author keywords was reviewed to identify the focus of research in the area of study. • The period between 2016 and 2018 saw more intense research on themes like HER, methylcyclohexane. • Hybrid compressed hydrogen systems are expected to significantly contribute to the emerging hydrogen economy. [ABSTRACT FROM AUTHOR]

In a hydrogen economy, the primary energy source for industry, transportation, and power production is hydrogen gas. Green hydrogen can be generated and utilized in an environmentally friendly and sustainable manner; it seeks to displace fossil fuels. Finding a clean alternative energy source is becoming more crucial due to the depletion of fossil fuels and the major environmental pollution issues they bring when utilized extensively. The paper's objective is to analyze the factors affecting the economy of green hydrogen production pathways for sustainable development to decarbonize the world and the associated challenges faced in terms of technological, social, infrastructure, and people's perceptions while adopting green hydrogen. To achieve this, the research looked at a variety of areas relevant to green hydrogen, such as production techniques, industry applications, benefits for society and the environment, and challenges that need to be overcome before the technology is widely used. The most recent methods of producing hydrogen from fossil fuels, such as steam methane, partial oxidation, autothermal, and plasma reforming, as well as renewable energy sources including biomass and thermochemical reactions and water splitting. Grey hydrogen is now the least expensive type of hydrogen, but, in the future, green hydrogen's levelized cost of hydrogen (LCOH) is expected to be less than $2 per kilogram of hydrogen. [ABSTRACT FROM AUTHOR]

Building a hydrogen economy is perceived as a way to achieve the decarbonization goals set out in the Paris Agreement to limit global warming, as well as to meet the goals resulting from the European Green Deal for the decarbonization of Europe. This article presents a literature review of various aspects of this economy. The full added value chain of hydrogen was analyzed, from its production through to storage, transport, distribution and use in various economic sectors. The current state of knowledge about hydrogen is presented, with particular emphasis on its features that may determine the positives and negatives of its development. It was noted that although hydrogen has been known for many years, its production methods are mainly related to fossil fuels, which result in greenhouse gas emissions. The area of interest of modern science is limited to green hydrogen, produced as a result of electrolysis from electricity produced from renewable energy sources. The development of a clean hydrogen economy is limited by many factors, the most important of which are the excessive costs of producing clean hydrogen. Research and development on all elements of the hydrogen production and use chain is necessary to contribute to increasing the scale of production and use of this raw material and thus reducing costs as a result of the efficiencies of scale and experience gained. The development of the hydrogen economy will be related to the development of the hydrogen trade, and the centers of this trade will differ significantly from the current centers of energy carrier trade. [ABSTRACT FROM AUTHOR]

Perovskites materials, due to their peculiar electronic and ionic properties, play a key role in the development of hydrogen-based technologies. Their flexible structure enables an easy tuning of various physical-chemical characteristics, such as ionic and electronic conductivity and redox active sites concentration, fundamental for these applications. Moreover, the same structure can exhibit different properties that can synergically act to improve the performance of the material for a specific application. [ABSTRACT FROM AUTHOR]

The chemical sector is the fourth largest industry in the European Union (EU) and the second largest chemical producer globally. However, its global share in chemicals sales has declined from 25% two decades ago to around 14% now. The sector, which accounts for 22% of the EU industry's energy demands, faces significant challenges in mitigating climate change, reducing pollution and toxicity, and improving circularity. Biomass, a promising renewable feedstock, currently represents only 3% of the sector's feedstocks. This review explores the opportunities and challenges for a bio‐based chemical sector in the EU, particularly plastics, to improve circularity and contribute to climate neutrality, reduction of pollution and toxicity. It provides an overview of current fossil‐based feedstocks, production processes, country‐specific trends, bio‐based production, and sustainability initiatives. Exploring new feedstocks such as lignin, organic residues, and algae can increase biomass availability toward a circular bioeconomy. Integrating chemicals and plastics production into commercial pulp and power factories, biofuel plants, and the sustainable hydrogen economy could boost the sector. Hydrogen is crucial for reducing biomass's oxygen content. These can ultimately contribute to reduce climate change impacts. Designing novel chemicals and plastics to accommodate biomass's higher oxygen content, reduce toxicity, and enhance biodegradability is essential. However, plastic waste mismanagement cannot be solved by merely replacing fossil feedstocks with biomass. Sustainability initiatives can strengthen and develop a circular bio‐based chemical sector, but better management of bio‐based plastic waste and transparent labeling of bio‐based products are needed. This calls for collaborative efforts among citizens, academia, policymakers, and industry. This article is categorized under:Climate and Environment > Circular EconomyClimate and Environment > Net Zero Planning and DecarbonizationEmerging Technologies > Materials [ABSTRACT FROM AUTHOR]

Li-ion battery is currently considered to be the most proven technology for energy storage systems when it comes to the overall combination of energy, power, cyclability and cost. However, there are continuous expectations for cost reduction in large-scale applications, especially in electric vehicles and grids, alongside growing concerns over safety, availability of natural resources for lithium, and environmental remediation. Therefore, industry and academia have consequently shifted their focus towards 'beyond Li-ion technologies'. In this respect, other non-Li-based alkali-ion/polyvalent-ion batteries, non-Li-based all solid-state batteries, fluoride-ion/ammonium-ion batteries, redox-flow batteries, sand batteries and hydrogen fuel cells etc. are becoming potential cost-effective alternatives. While there has been notable swift advancement across various materials, chemistries, architectures, and applications in this field, a comprehensive overview encompassing high-energy 'beyond Li-ion' technologies, along with considerations of commercial viability, is currently lacking. Therefore, in this review article, a rationalized approach is adopted to identify notable 'post-Li' candidates. Their pros and cons are comprehensively presented by discussing the fundamental principles in terms of material characteristics, relevant chemistries, and architectural developments that make a good high-energy 'beyond Li' storage system. Furthermore, a concise summary outlining the primary challenges of each system is provided, alongside the potential strategies being implemented to mitigate these issues. Additionally, the extent to which these strategies have positively influenced the performance of these 'post-Li' technologies is discussed. [ABSTRACT FROM AUTHOR]

Can Norway be an important hydrogen exporter to the European Union (EU) by 2030? We explore three scenarios in which Norway's hydrogen export market may develop: A Business-as-usual, B Moderate Onshore, C Accelerated Offshore. Applying a sector-coupled energy system model, we examine the techno-economic viability, spatial and socio-economic considerations for blue and green hydrogen export in the form of ammonia by ship. Our results estimate the costs of low-carbon hydrogen to be 3.5–7.3€/kg hydrogen. While Norway may be cost-competitive in blue hydrogen exports to the EU, its sustainability is limited by the reliance on natural gas and the nascent infrastructure for carbon transport and storage. For green hydrogen exports, Norway may leverage its strong relations with the EU, but is less cost-competitive than countries like Chile and Morocco, which benefit from cheaper solar power. For all scenarios, significant land use is needed to generate enough renewable energy. Developing a green hydrogen-based export market requires policy support and strategic investments in technology, infrastructure and stakeholder engagement, ensuring a more equitable distribution of renewable installations across Norway and national security in the north. Using carbon capture and storage technologies and offshore wind to decarbonise the offshore platforms is a win-win solution that would leave more electricity for developing new industries and demonstrate the economic viability of these technologies. Finally, for Norway to become a key hydrogen exporter to the EU will require a balanced approach that emphasises public acceptance and careful land use management to avoid costly consequences. • Costs range at €3.50–4.23/kg blue hydrogen, or €5.18–7.25/kg green hydrogen. • Norway has a price advantage over global suppliers for blue hydrogen export to the EU. • Norwegian green hydrogen may be undercut by global suppliers with cheaper electricity. • Offshore wind-based hydrogen is more politically acceptable, but is more expensive. • Balancing blue and green hydrogen exports involves short- and long-term trade-offs. [ABSTRACT FROM AUTHOR]

The proposed study is devoted to defining a set of means, methods and conditions that enable the creation of a sustainable and efficient hydrogen economy in Ukraine for the period up to 2030. The study itself is aimed at studying the features of the operation of the hydrogen square concept, which illustrates the various stages of the hydrogen value chain from production to final use, and the potential opportunities for the development of the hydrogen economy in Ukraine until 2030. Using the hydrogen square, safeguards across the entire hydrogen value chain – production, storage, transport and use – are discussed, highlighting the need for a balanced approach to ensure a sustainable and efficient hydrogen economy. It has been determined that the greatest potential opportunities for the development of the hydrogen economy in Ukraine for the period up to 2030 are the transportation of a mixture of hydrogen with natural gas (gitan) through the Ukrainian GTS and the production of methane from green hydrogen (synthetic methane) through the implementation of Power-to-Gas technology. It has been found that the readiness of gas transport networks to transport a mixture of hydrogen with natural gas (gitan) differs greatly in different EU countries, and the industry itself is currently at a very early stage of development. Blending is likely to be a temporary or transitional solution, given the existence of a technical and economic limit to the volume of hydrogen concentration that traditional gas infrastructure can handle. The possibility of using Power-to-Gas technology in Ukraine, in the city of Dnipro, is described. The production of synthetic methane through the implementation of the Power-to-Gas technology will provide an opportunity to obtain the gitan mixture without the use of fossil fuels in the future, which will enable the hydrogen economy to function completely without fossil fuels.

This study assessed the most pertinent themes connected to hydrogen fuel cells and vehicles through a bibliometric analysis to thoroughly understand hydrogen fuel cell and vehicle technologies and comprehend the focus of current and future research directions. This study chose the Scopus database, which is considered the largest database containing pertinent documents for bibliometric analysis. A total of 3107 relevant documents were retrieved between the period of 2003 and 2023 and analyzed using visualization tools like the Biblioshiny package in R and the VOSviewer software. According to the analyses, the study involved 724 authors, 15% international co-authorship, 3.74 global co-authors per document, 5463 keywords, and 21.24 citations per document. Research trends related to deploying and optimizing various technologies, such as hydrogen fuel cell vehicles, refueling stations, and machine learning for energy management, are the most evident themes in the most recent 2022–2023 period. The study identified some research gaps on the topic and recommended them as future research potentials. • This study reviewed the development in hydrogen fuel cells and vehicles. • The current trends and potential future research directions on the subject were analyzed. • A total of 3107 relevant documents between 2003 and 2023 were reviewed. • The study involved 724 authors, and 15% international co-authorship. • China tops globally in terms of research output on the subject of study. [ABSTRACT FROM AUTHOR]

This work analyses the trading of strategic merchant hydrogen technologies in energy and ancillary services markets. The hydrogen firms trade in two markets: (1) a joint hydrogen and energy/reserves day-ahead market and (2) the balancing settlements market. We contrast the co-optimised markets with trading in an energy-only market. Trading both energy and ancillary services leads hydrogen firms to produce and use more hydrogen, leading to less reliance on fossil fuels and an increase in the revenue streams of the electrolysis-based firms. The problem is formulated as a stochastic multi-leader-multi-follower model. Each leader firm solves a bi-level Stackelberg problem. The upper-level is the Nash game among strategic firms. The lower-level is an instance of a Generalised Nash Equilibrium of the followers. • Strategic hydrogen firms modelled in an energy market. • Stackelberg equilibrium found via diagonalisation. • Hydrogen providing reserves boosts hydrogen usage. • Ancillary services shift from SMR to electrolysis. [ABSTRACT FROM AUTHOR]

This paper provides an in-depth examination of critical and strategic raw materials (CRMs) and their crucial role in the development of electrolyzer and fuel cell technologies within the hydrogen economy. It methodically analyses a range of electrolyzer technologies, including alkaline, proton-exchange membrane, solid-oxide, anion-exchange membrane, and proton-conducting ceramic systems. Each technology is examined for its specific CRM dependencies, operational characteristics, and the challenges associated with CRM availability and sustainability. The study further extends to hydrogen storage and separation technologies, focusing on the materials employed in high-pressure cylinders, metal hydrides, and hydrogen separation processes, and their CRM implications. A key aspect of this paper is its exploration of the supply and demand dynamics of CRMs, offering a comprehensive view that encompasses both the present sttate and future projections. The aim is to uncover potential supply risks, understand strategies, and identify potential bottlenecks for materials involved in electrolyzer and fuel cell technologies, addressing both current needs and future demands as well as supply. This approach is essential for the strategic planning and sustainable development of the hydrogen sector, emphasizing the importance of CRMs in achieving expanded electrolyzer capacity leading up to 2050. • Analyzes CRMs in hydrogen tech, focusing on electrolyzers and fuel cells. • Explores CRM implications in hydrogen storage and separation. • Investigates CRM supply and demand, identifying risks and strategies. • Highlights the role of CRMs in sustainable hydrogen sector development. [ABSTRACT FROM AUTHOR]

As new sources of energy and advanced technologies are used, there is a continuous evolution in energy supply, demand, and distribution. Advanced nuclear reactors and clean hydrogen have the opportunity to scale together and diversify the hydrogen production market away from fossil fuel-based production. Nevertheless, the technical uncertainties surrounding nuclear hydrogen processes necessitate thorough research and a solid development effort. This paper aims to position pink hydrogen for nuclear hydrogen production at the forefront of sustainable energy-related solutions by offering a comprehensive review of recent advancements in nuclear hydrogen production, covering both research endeavors and industrial applications. It delves into various pink hydrogen generation methodologies, elucidating their respective merits and challenges. Furthermore, this paper analyzes the evolving landscape of pink hydrogen in terms of its levelized cost by comparatively assessing different production pathways. By synthesizing insights from academic research and industrial practices, this paper provides valuable perspectives for stakeholders involved in shaping the future of nuclear hydrogen production. [ABSTRACT FROM AUTHOR]

[Display omitted] Electrochemical water electrolysis is a promising method for sustainable hydrogen production while transiting towards hydrogen economy. Among many, the Anion Exchange Membrane (AEM) based water electrolyzer is an emerging yet potentially affordable technology on maturity for producing large-scale hydrogen accommodating the usage of Non-Platinum Group Metal (non-PGM) based inexpensive electrocatalysts. Herein, we demonstrate the excellent performance of a bifunctional Nickel Copper Phosphide-Nickel sulphide (NCP-NS) electrocatalyst with a unique tensile nanostructure obtained via a facile, controlled ambient galvanic displacement route. An AEM electrolyzer with a larger active area of 10 cm2 stacked with the symmetric NCP-NS electrodes and a membrane demonstrates scalability with a requirement of a mere 1.66 V to reach a current density of 10 mA cm−2. The nickel-copper phosphide boosts the kinetics of charge transfer between the electrode and electrolyte interface, while a unique combination of a few nickel sulphide phases present in the catalyst provides sufficiently appropriate active sites for the overall water electrolysis. For the first time, we report a room temperature performance of ∼ 230 mA cm−2 at 2 V for a non-PGM-based bifunctional electrocatalyst with exceptional durability for over 300 h of operation in an AEM water electrolyser with a retention rate of 95 %-97 % at a current density range of 80–800 mA cm−2. [ABSTRACT FROM AUTHOR]