Electrolysis Technology Research Articles

Low-Level Fe Doping in CoMoO4 Enhances Surface Reconstruction and Electronic Modulation Creating an Outstanding OER Electrocatalyst for Water Splitting.

Efficient and stable nonprecious metal-based oxygen evolution reaction (OER) electrocatalysts are pivotal for water electrolysis technology. Herein, we are reporting an effective strategy for fabricating efficient Co-based OER electrocatalysts by low-level Fe doping in CoMoO4 to boost surface reconstruction and electronic modulation, which resulted in excellent OER electroactivity consequently. Our findings reveal that a mere 5.30% (wt %) of Fe doping can raise the O 2p band center energy nearer to the Fermi level, reduce the energy barrier for oxygen vacancy (VO) formation, and significantly enhance OER electrocatalytic activity. Additionally, the fast dissolution of Mo in the initial reaction facilitated surface reconstruction to form active oxyhydroxide species and stabilized Fe and Co from leaching. As a result, the optimized catalyst Fe-CoMoO4-0.2 exhibited a low overpotential of 276 mV at 10 mA cm-2 in 1 M KOH and can operate stably at a current density of 20 mA cm-2 for at least 24 h under water splitting conditions. This work provides an excellent example of regulating the surface structure and electronic properties of the OER catalysts.

W-mediated electron accumulation in Ru-O-W motifs enables ultra-stable oxygen evolution reaction in acid.

The development of efficient and durable oxygen evolution reaction (OER) catalysts is crucial for advancing proton exchange membrane water electrolysis (PEMWE) technology, especially in the pursuit of non-iridium alternatives. Herein, we report a Zn, W co-doping Ru3Zn0.85W0.15Ox (RZW) ternary oxide catalyst that exhibits a low overpotential of 200 mV and remarkable stability for over 4000 hours at 10 mA cm-2 in 0.1 M HClO4. The incorporation of highly electronegative W facilitates the efficient capture of electrons released from the sacrificial Zn species during OER, and subsequently mediated to Ru sites. The observed enhancement in electron density within the stable Ru-O-W motifs substantially improve the anti-overoxidation properties of the Ru active sites. Our findings highlight the importance of strategic metal doping in modulating the electronic structure of OER catalysts during operation, thereby facilitating the development of practical and long-lasting water electrolysis technologies.

Ru@MnO2 core@shell nanowires as a bifunctional electrocatalyst for efficient solar-driven seawater splitting.

Seawater electrolysis technology for hydrogen production has attracted worldwide attention due to the abundant seawater resources. Herein, we proposed core-shell Ru@MnO2 nanowires (NWs) with α/β-MnO2 NWs as the core and amorphous Ru as the shell, in which the Ru@α-MnO2 NWs exhibited lower overpotential and better stability. More importantly, they can operate stably as a bifunctional catalyst for more than 250 h and maintain excellent catalytic performance when driven by solar energy.

Water Electrolysis Facing the Gigawatt Challenge—Comprehensive De‐Risking of Proton Exchange Membrane and Anion Exchange Membrane Electrolyser Technology

Water Electrolysis Facing the Gigawatt Challenge—Comprehensive De‐Risking of Proton Exchange Membrane and Anion Exchange Membrane Electrolyser Technology

The future of industrial hydrogen: renewable sources and applications for the next 15 years

Abstract This paper explores the potential industrial applications of hydrogen produced from renewable sources, focusing on anticipated advancements and adoption over the next 15 years. With the global shift toward defossilation, renewable hydrogen presents a compelling solution to reduce industrial greenhouse gas emissions. The article examines various production methods, cost projections, technological challenges, and key industries that will benefit from renewable hydrogen integration. Renewable hydrogen is anticipated to play a critical role in industrial defossilation over the next 15 years. As industries and governments seek to meet climate targets, hydrogen’s versatility as a fuel and feedstock positions it well for applications across various sectors, including heavy industry, transportation, and power generation. Challenges remain in cost, efficiency, and infrastructure, but ongoing advancements in electrolysis technology and supportive policies are expected to drive down costs. Successful deployment will also depend on international collaboration, regulatory frameworks, and public acceptance. The case studies and pilot projects highlighted in this paper provide evidence of the promising future for renewable hydrogen in industrial applications.

Co-production of hydrogen, oxygen, and electricity via an integrated solar-driven system with decoupled water electrolyzer and Na-Zn ion battery

Combining water electrolysis and rechargeable battery technologies into a single system holds great promise for the co-production of hydrogen (H2) and electricity. However, the design and development of such systems is still in its infancy. Herein, an integrated hydrogen-oxygen (O2)-electricity co-production system featuring a bipolar membrane-assisted decoupled electrolyzer and a Na-Zn ion battery was established with sodium nickelhexacyanoferrate (NaNiHCF) and Zn2+/Zn as dual redox electrodes. The decoupled electrolyzer enables to produce H2 and O2 in different time and space with almost 100% Faradic efficiency at 100 mA cm−2. Then, the charged NaNiHCF and Zn electrodes after the electrolysis processes formed a Na-Zn ion battery, which can generate electricity with an average cell voltage of 1.75 V at 10 mA cm−2. By connecting Si photovoltaics with the modular electrochemical device, a well-matched solar driven system was built to convert the intermittent solar energy into hydrogen and electric energy with a solar to hydrogen-electricity efficiency of 16.7%, demonstrating the flexible storage and conversion of renewables.

Highly conductive and stable electrolytes for solid oxide electrolysis and fuel cells: fabrication, characterisation, recent progress and challenges

Solid oxide electrolyser (SOE) technology emerges as a promising alternative, typified by high-efficiency water-splitting capability and lower cost for large-scale hydrogen production. Electrolytes are the critical part of SOECs and SOFCs, which affect the performance and operation temperatures.

Design and synthesis of autogenous growth NiFe bimetallic phosphide catalysts on a nickel iron foam-like substrate for efficient overall water splitting.

The design of low-cost, highly active, and stable electrocatalysts is pivotal for advancing water electrolysis technologies. In this study, carbonyl iron powder (CIP) was anchored within the pores of nickel foam (NF) by electroplating nickel, creating nickel iron foam-like (NFF-L) substrates. Subsequently, nickel-iron hydroxide (NiFe-OH) was synthesized on the NFF-L substrate employing an autogenous growth strategy, followed by a phosphating treatment that produced a nanoflower-like NiFe bimetallic phosphide heterostructure catalyst (Fe2P-Ni2P@NFF-L). This novel method of substrate filling enhanced space utilization, while the presence of micropores and mesopores on the nanosheet surfaces facilitated electrolyte infiltration and ion diffusion, thereby significantly increasing the specific surface area. The formation of a two-phase heterointerface accelerated electron transmission and transfer, enhancing water dissociation and the adsorption of hydrogen adatoms (Had). In addition, under anodic oxidation conditions, the dynamic surface reconstruction facilitated a synergistic interaction between the highly active β-NiOOH and α-FeOOH phases, which significantly contributed to the catalyst's exceptional intrinsic activity for the oxygen evolution reaction (OER).

Prospective life cycle assessment of cost-effective pathways for achieving the FuelEU Maritime Regulation targets.

To reduce environmental impacts from the shipping industry, the FuelEU Maritime Regulation has set a binding 80% reduction target for well-to-wake (WTW) greenhouse gas (GHG) emissions by 2050. This article presents a prospective life cycle assessment (LCA) comparing the environmental impacts of e-ammonia, e-methanol, e-Fischer Tropsch (FT) diesel, and e-liquefied natural gas (LNG)-for maritime applications in Europe. In addition to e-fuels, traditional propulsion technologies using very low sulfur fuel oil (VLSFO) and LNG are assessed, both with and without integrating ship-based carbon capture (SBCC) systems. Key factors considered include the impact of different production locations in Europe, electrolysis technology choices, and global climate policies. Beyond analysing the environmental footprints, the study examines the economic and externality costs associated with each fuel option, contextualizing these findings within the GHG mitigation targets set by the FuelEU Maritime regulation. The results indicate that e-ammonia, e-FT diesel, and e-methanol could meet the 2050 FuelEU Maritime target, but e-LNG and SBCCS could not. Although it is the most immature technology, e-ammonia could be the cheapest option with the lowest overall environmental impacts. E-LNG shows higher life cycle climate change impacts due to ship-level methane slip but has lower impacts across other environmental categories because of low NOx emissions. E-methanol has higher toxicity risks over the life cycle and higher costs.

Development and application of ordered membrane electrode assemblies for water electrolysis.

With the development of hydrogen energy, there has been increasing attention toward fuel cells and water electrolysis. Among them, the zero-gap membrane electrode assembly (MEA) serves as an important triple-phase reaction site that determines the performance and efficiency of the reaction system. The development of efficient and durable MEAs plays a crucial role in the development of hydrogen energy. Consequently, a great deal of effort has been devoted to developing ordered MEAs that can effectively increase catalyst utilization, maximize triple-phase boundaries, enhance mass transfer and improve stability. The research progress of ordered MEAs in recent advances is highlighted, involving hydrogen fuel cells and low temperature water electrolysis technology. Firstly, the fundamental scientific understanding and structural characteristics of MEAs based on one-dimensional nanostructures such as nanowires, nanotubes and nanofibers are summarized. Then, the classification, preparation and development of ordered MEAs based on three-dimensional structures are summarized. Finally, this review presents current challenges and proposes future research on ordered MEAs and offers potential solutions to overcome these obstacles.

Solid Oxide Electrolysis, Co-Electrolysis, and Methanation Fundamentals of Performance and History

This manuscript discusses the advancements and historical development of solid oxide electrolysis (SOE), co-electrolysis, and methanation technologies, addressing the performance fundamentals and system integration challenges in the context of the EU’s 2050 climate neutrality goals. SOE technologies, characterized by their high efficiencies and ability to operate at elevated temperatures, offer significant advantages in hydrogen production and power generation. Co-electrolysis of steam and carbon dioxide in SOEs provides a promising pathway for syngas production, leveraging carbon capture and utilization strategies to mitigate carbon emissions. Additionally, catalytic methanation processes described within facilitate the synthesis of methane from carbon oxides and hydrogen, which could be integral to renewable energy storage and grid-balancing solutions. Historical analysis provides insights into the evolution of these technologies from early experiments to modern applications, including their role in space programmes and potential for industrial scale-up. The current state of research and commercialization, highlighted through various system designs and operational enhancements, suggests that SOEs are crucial for sustainable energy transformations, underscoring the necessity for continued innovation and deployment in relevant sectors.

A Comprehensive Overview of Technologies Applied in Hydrogen Valleys

Hydrogen valleys are encompassed within a defined geographical region, with various technologies across the entire hydrogen value chain. The scope of this study is to analyze and assess the different hydrogen technologies for their application within the hydrogen valley context. Emphasizing on the coupling of renewable energy sources with electrolyzers to produce green hydrogen, this study is focused on the most prominent electrolysis technologies, including alkaline, proton exchange membrane, and solid oxide electrolysis. Moreover, challenges related to hydrogen storage are explored, alongside discussions on physical and chemical storage methods such as gaseous or liquid storage, methanol, ammonia, and liquid organic hydrogen carriers. This article also addresses the distribution of hydrogen within valley operations, especially regarding the current status on pipeline and truck transportation methods. Furthermore, the diverse applications of hydrogen in the mobility, industrial, and energy sectors are presented, showcasing its potential to integrate renewable energy into hard-to-abate sectors.

Fabrication and Coating of Porous Ti6Al4V Structures for Application in PEM Fuel Cell and Electrolyzer Technologies.

The production of green hydrogen through proton exchange membrane water electrolysis (PEMWE) is a promising technology for industry decarbonization, outperforming alkaline water electrolysis (AWE). However, PEMWE requires significant investment, which can be mitigated through material and design advancements. Components like bipolar porous plates (BPPs) and porous transport films (PTFs) contribute substantially to costs and performance. BPPs necessitate properties like corrosion resistance, electrical conductivity, and mechanical integrity. Titanium, commonly used for BPPs, forms a passivating oxide layer, reducing efficiency. Effective coatings are crucial to address this issue, requiring conductivity and improved corrosion resistance. In this study, porous Ti64 structures were fabricated via powder technology, treating them with thermochemical nitriding. The resulting structures with controlled porosity exhibited enhanced corrosion resistance and electrical conductivity. Analysis through scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), grazing incidence XRD and X-ray photoelectron spectroscopy (XPS) confirmed the effectiveness of the coating, meeting performance requirements for BPPs.

High-Performance Pure Water-Fed Anion Exchange Membrane Water Electrolysis with Patterned Membrane via Mechanical Stress and Hydration-Mediated Patterning Technique.

Despite rapid advancements in anion exchange membrane water electrolysis (AEMWE) technology, achieving pure water-fed AEMWE remains critical for system simplification and cost reduction. Under pure water-fed conditions, electrochemical reactions occur solely at active sites connected to ionic networks. This study introduces an eco-friendly patterning technique leveraging membrane swelling properties by applying mechanical stress during dehydration under fixed constraints. The method increases active sites by creating additional hydroxide ion pathways at the membrane-electrode interface, eliminating the need for additional ionomers in the electrode. This innovation facilitates ion conduction via locally shortened pathways. Membrane electrode assemblies (MEAs) with patterned commercial membranes demonstrated significantly improved performance and durability compared to MEAs with conventional catalyst-coated substrates and flat membranes under pure water-fed conditions. The universal applicability of this technique was confirmed using in-house fabricated anion exchange membranes, achieving exceptional current densities of 13.7 A cm-2 at 2.0 V in 1.0 M potassium hydroxide (KOH) and 2.8 A cm-2 at 2.0 V in pure water at 60°C. Furthermore, the scalability of the technique was demonstrated through successful fabrication and operation of large-area cells. These findings highlight the potential of this patterning method to advance AEMWE technology, enabling practical applications under pure water-fed conditions.

Synthesis and characterization of ASU-PPO based anion exchange membrane with PEG support for water electrolysis

Abstract Polymer electrolyte membrane-based water electrolysis technology is a productive method for converting electrical energy into hydrogen. To improve and optimize the performance of the water electrolytic system, an anion exchange membrane (AEM) water electrolyzer is an excellent choice. AEM possess inadequacies in cation structural design, and diversity in development approaches with each new cation inclusion. This study focuses on the synthesis and characterization of a variety of poly (2,6-dimethyl-1,4-phenylene oxide) (PPO)-based AEMs crosslinked with azonia-spiro undecane (ASU). The design process consists of three steps: first P-ASU making followed by quaternarization and then PPO bromination, followed by P-ASU and BPPO crosslinking. The membrane’s stability is enhanced by adding polyethylene glycol (PEG). PPO has outstanding mechanical and thermal stability, and its backbone can be functionalized through a variety of ways. Bromination was performed with quantitative control in this study. The developed membrane was examined using analytical tools (e.g., TGA, FTIR, HNMR, SEM). The results revealed that membrane demonstrated sufficient thermal stability between 150 °C and 250 °C as degradation phase. Characterization results also contribute to accurately measuring membrane surface morphology and stability at 4.38 ppm and 3.13–3.24 ppm transition from the–CH2Br group to the–N+(CH3)3 groups by new peaks. The composition and properties were analyzed to validate successful crosslinking and functionalization of the membrane.

Electrode Selection and Catalyst Evaluation in Hydrogen Production from Alkaline Water Electrolysis: A Review

Generating hydrogen, through alkaline water electrolysis shows promise as an energy source. This review delves into the significance of choosing the electrodes and evaluating catalysts to enhance the efficiency and performance of hydrogen production. It summarizes the activation energy and losses linked to reactions in alkaline electrolysis emphasizing the necessity for electrode materials and catalysts. The review also touches upon challenges such as electricity consumption and platinum group metal based electro catalysts proposing various electrode materials and catalysts with superior activity and selectivity for hydrogen production. Additionally, it discusses electrolysis cell designs that facilitate separating by-products from hydrogen gas. The study reveals that with low over potentials of 70, 318, and 361 mV at 10, 500, and 1000 mA cm−2, respectively, NiOx/NF exhibits strong alkaline hydrogen evolution activity, resulting in great performance in alkaline HER. Moreover, it outlines advancements in alkaline water electrolysis technology focusing on enhanced efficiency and reduced operating costs associated with electricity consumption. Overall this review underscores the role of selecting electrodes and evaluating catalysts in optimizing hydrogen production from alkaline water electrolysis.

Life cycle environmental impacts and costs of water electrolysis technologies for green hydrogen production in the future

BackgroundTo limit climate change and reduce further harmful environmental impacts, the reduction and substitution of fossil energy carriers will be the main challenges of the next few decades. During the United Nations Climate Change Conference (COP28), the participants agreed on the beginning of the end of the fossil fuel era. Hydrogen, when produced from renewable energy, can be a substitute for fossil fuel carriers and enable the storage of renewable energy, which could lead to a post-fossil energy age. This paper outlines the environmental impacts and levelized costs of hydrogen production during the life cycle of water electrolysis technologies.ResultsThe environmental impacts and life cycle costs associated with hydrogen production will significantly decrease in the long term (until 2045). For the case of Germany, the worst-case climate change results for 2022 were 27.5 kg CO2eq./kg H2. Considering technological improvements, electrolysis operation with wind power and a clean heat source, a reduction to 1.33 kg CO2eq./kg H2 can be achieved by 2045 in the best case. The electricity demand of electrolysis technologies is the main contributor to environmental impacts and levelized costs in most of the considered cases.ConclusionsA unique combination of possible technological, environmental, and economic developments in the production of green hydrogen up to the year 2045 was presented.Based on a comprehensive literature review, several research gaps, such as a combined comparison of all three technologies by LCA and LCC, were identified, and research questions were posed and answered. Consequently, prospective research should not be limited to one type of water electrolysis but should be carried out with an openness to all three technologies. Furthermore, it has been shown that data from the literature for the LCA and LCC of water electrolysis technologies differ considerably in some cases. Therefore, extensive research into material inventories for plant construction and into the energy and mass balances of plant operation are needed for a corresponding analysis to be conducted. Even for today’s plants, the availability and transparency of the literature data remain low and must be expanded.

Pioneering Built-In Interfacial Electric Field for Enhanced Anion Exchange Membrane Water Electrolysis.

As a half-reaction in anion exchange membrane water electrolysis (AEMWE) technology, the hydrogen evolution reaction (HER) at the cathode is severely hindered by the sluggish reaction kinetics involved in additional water dissociation step, which results in large overpotentials and low energy conversion efficiency. Here, we develop a nano-heterostructure composed of ultra-thin W5N4 shells over Ni3N nanoparticles (Ni3N@W5N4) as efficient catalysts, in which built-in interfacial electric field (BIEF) is created owing to the distinct lattice arrangements and work functions of biphasic metal nitrides. The BIEF facilitates the electron localization around the interface and enables high valence W and more exposed binding sites in the surface W5N4 shell for accelerating the water dissociation step, ultimately leading to a remarkable reduction in the energy barriers of RDS from 1.40 eV to 0.26 eV. Theoretical calculations and operando X-ray absorption spectroscopy analysis results demonstrated that surface W5N4 serves as the active species for HER. Moreover, the ultra-thin shell characteristics enable the optimized W5N4 with enhanced intrinsic catalytic activity to be fully exposed as active sites. Consequently, the Ni3N@W5N4 exhibits exceptional performance in alkaline HER (60 mV@10 mA cm-2) and remarkable long-term stability (500 mA cm-2 for 100 hours). When employed as the cathode in the AEMWE device, the synthesized Ni3N@W5N4 demonstrates stable performance for 90 hours at a current density of 1 A cm-2.

Pioneering Built‐In Interfacial Electric Field for Enhanced Anion Exchange Membrane Water Electrolysis

AbstractAs a half‐reaction in anion exchange membrane water electrolysis (AEMWE) technology, the hydrogen evolution reaction (HER) at the cathode is severely hindered by the sluggish reaction kinetics involved in additional water dissociation step, which results in large overpotentials and low energy conversion efficiency. Here, we develop a nano‐heterostructure composed of ultra‐thin W5N4 shells over Ni3N nanoparticles (Ni3N@W5N4) as efficient catalysts, in which built‐in interfacial electric field (BIEF) is created owing to the distinct lattice arrangements and work functions of biphasic metal nitrides. The BIEF facilitates the electron localization around the interface and enables high valence W and more exposed binding sites in the surface W5N4 shell for accelerating the water dissociation step, ultimately leading to a remarkable reduction in the energy barriers of RDS from 1.40 eV to 0.26 eV. Theoretical calculations and operando X‐ray absorption spectroscopy analysis results demonstrated that surface W5N4 serves as the active species for HER. Moreover, the ultra‐thin shell characteristics enable the optimized W5N4 with enhanced intrinsic catalytic activity to be fully exposed as active sites. Consequently, the Ni3N@W5N4 exhibits exceptional performance in alkaline HER (60 mV@10 mA cm−2) and remarkable long‐term stability (500 mA cm−2 for 100 hours). When employed as the cathode in the AEMWE device, the synthesized Ni3N@W5N4 demonstrates stable performance for 90 hours at a current density of 1 A cm−2.

Green hydrogen production by PEM water electrolysis up to the year 2050: Prospective life cycle assessment using learning curves

AbstractWater electrolysis technologies for producing green hydrogen are promising options for avoiding the use of fossil fuels and thus limiting climate change. Hydrogen can be used in a variety of sectors, enabling sector coupling, and strengthening the security of the energy supply through its storability. Environmental impacts provoked by green hydrogen production are comparatively low and improving manufacturing processes and technological advances will enable to further reduce the demand for raw materials and electricity and thus the environmental impacts. The objective of this study is to compare the status quo with prospective trends and target values. Learning curves of expected specific electricity demand and critical raw material (CRM) intensity are applied, and environmental impacts are subsequently analyzed via life cycle assessment. This study focuses on the polymer electrolyte membrane water electrolysis technology. As a result of the calculated learning curves, the CRM intensity could be reduced by more than 96% between 2022 and 2050. The specific electricity demand is projected to be reduced by 11.2%–22.5%. Combining the extrapolated reductions of electricity and CRM demand, a climate change impact decrease of 16.5%–28.5% is possible for green hydrogen production until the year 2050.