Proton Exchange Membrane Electrolyzer Research Articles

Mitigation of Performance Degradation of PEM Water Electrolyzers by Power Distribution Control of Fluctuating Renewable Energy

Durability of a PEM electrolysis cell against voltage fluctuation prepared from actual wind power data was analyzed. Two fluctuation patterns were prepared; the pattern A prepared by scaling the wind power data and the pattern B prepared by applying the power distribution control (PDC), that is, converting the pattern A into an alternative sequence of a high-operating rate pattern and a low-operating rate pattern. During 240-h durability tests, the current density continuously decreased for the pattern A, while no distinguishable decrease was observed for the pattern B except the initial 30 h. It was found that the performance degradation is mostly reversible and attributed to increase in the diffusion overpotential consistently with the previous studies. Our results suggest that the PDC suppresses reversible degradation by avoiding gas stagnation at the anode surface, which is important for mitigating irreversible degradation during long-term operation.

Green hydrogen prospects in Peninsular Malaysia: a techno-economic analysis via Monte Carlo simulations

According to Malaysia's National Energy Transition Roadmap, hydrogen is a critical component of the country's energy transition. However, there is a scarcity of hydrogen studies for Peninsular Malaysian states, which limits discussions on green hydrogen production. This study employs a Monte Carlo model to assess the economic and technical factors influencing the success of green hydrogen in Peninsular Malaysia. The study focuses on three target years: 2023, 2030, and 2050, representing various stages of technological development and market adoption. The levelized cost of hydrogen (LCOH) of a 1-MW Proton Exchange Membrane (PEM) electrolyzer system ranges from $5.39 to $10.97 per kg in 2023, highlighting early-stage challenges and uncertainties. A 6-MW PEM electrolyzer system could achieve an LCOH of $3.50 to $4.72 per kg by 2030, indicating better prospects. Because of technological advancements and cost reductions, a 20-MW PEM electrolyzer system could achieve an LCOH of $3.12 to $3.64 per kg in 2050. The findings indicate that the northern regions of Peninsular Malaysia have consistently low LCOH values due to favorable geographical conditions. Due to minor variations in solar capacity factors, uncertainty distributions in LCOH remain stable across different regions. Some states may face increased uncertainty, emphasizing the need for additional policy support mechanisms to mitigate risks associated with green hydrogen investments. The sensitivity analysis shows that key cost drivers are shifting, with early-stage electrolyzer investments dominating in 2023 and electricity prices becoming more important in 2030 and 2050. Future research could focus on optimizing green hydrogen systems for areas with underdeveloped green hydrogen industries. This study contributes to informed discussions about green hydrogen production by emphasizing the importance of tailored strategies that consider local conditions and highlighting the role of Peninsular Malaysia in the energy transition.

Evaluating the techno-economic feasibility of hydrogen-fuelled reciprocating engines for renewable base-load power generation

This study investigates the techno-economic feasibility of a photovoltaic power plant integrated with hydrogen energy storage and a dual-fuel reciprocating engine for gas-to-power and power-to-gas operations. The system is optimised for maximising constant grid supply, minimising CO2 emissions, and lowering the levelised cost of electricity (LCOE) to assess its value in future energy landscape. Multi-objective optimisation identified a configuration with a hydrogen-fuelled engine generator offering a constant 10 MW grid supply with minimal CO2 emissions (78 kg/MWh), at a LCOE of $335.52/MWh. This system comprises a 93 MW PEM electrolyser, a 4 MW compressor, and 29 t of compressed hydrogen storage, within the limits of the industry’s current or projected capacities. A key highlight of the engine-based approach is its ability to readily enhance grid supply through increased diesel consumption without significantly impacting LCOE, provided CO2 emissions stay within acceptable sector cap. This flexibility surpasses alternative technologies. Further analysis explored potential LCOE reductions using global projected data, bringing optimised LCOE values down to $138.76/MWh, making it competitive to current market prices. Sensitivity analysis revealed the LCOE’s highest sensitivity to the discount rate, followed by minimal impact from variations in fuel and electricity prices due to the optimised system configuration. Furthermore, the tightening CO2 emission limits do not affect the optimised system’s performance, except for limiting the maximum achievable grid supply in 2050 by increased diesel reliance.

Coordinated Control of Proton Exchange Membrane Electrolyzers and Alkaline Electrolyzers for a Wind-to-Hydrogen Islanded Microgrid

In recent years, the development of hydrogen energy has been widely discussed, particularly in combination with renewable energy sources, enabling the production of “green” hydrogen. With the significant increase in wind power generation, a promising solution for obtaining green hydrogen is the development of wind-to-hydrogen (W2H) systems. However, the high proportion of wind power and electrolyzers in a large-scale W2H system will bring about the problem of renewable energy consumption and frequency stability reduction. This paper analyzes the operational characteristics and economic feasibility of mainstream electrolyzers, leading to the proposal of a coordinated hydrogen production scheme involving both a proton exchange membrane (PEM) electrolyzer and an alkaline (ALK) electrolyzer. Subsequently, a coordinated control based on Model Predictive Control (MPC) is proposed for system frequency regulation in a large-scale W2H islanded microgrid. Finally, simulation results demonstrate that the system under PEM/ALK electrolyzers coordinated control not only flexibly accommodates fluctuating wind power but also maintains frequency stability in the face of large disturbances. Compared with the traditional system with all ALK electrolyzers, the frequency deviation of this system is reduced by 25%, the regulation time is shortened by 80%, and the demand for an energy storage system (ESS) is reduced. The result validates the effectiveness of MPC and the benefits of the PEM/ALK electrolyzers coordinated hydrogen production scheme.

Atomically dispersed hexavalent iridium oxide from MnO2 reduction for oxygen evolution catalysis.

Hexavalent iridium (IrVI) oxide is predicted to be more active and stable than any other iridium oxide for the oxygen evolution reaction in acid; however, its experimental realization remains challenging. In this work, we report the synthesis, characterization, and application of atomically dispersed IrVI oxide (IrVI-ado) for proton exchange membrane (PEM) water electrolysis. The IrVI-ado was synthesized by oxidatively substituting the ligands of potassium hexachloroiridate(IV) (K2IrCl6) with manganese oxide (MnO2). The mass-specific activity (1.7 × 105 amperes per gram of iridium) and turnover number (1.5 × 108) exceeded those of benchmark iridium oxides, and in situ x-ray analysis during PEM operations manifested the durability of IrVI at current densities up to 2.3 amperes per square centimeter. The high activity and stability of IrVI-ado showcase its promise as an anode material for PEM electrolysis.

A “Leaf‐Vein” Flow Channel Design for the Improvement of Oxygen Transporting in a Large‐Scale Proton Exchange Membrane Electrolysis Cell

In a proton exchange membrane electrolysis cell (PEMEC), the oxygen generated on the anode side diffuses into the flow channel and forms a gas–liquid two‐phase flow with liquid water. In order to increase the production of hydrogen, larger sized PEMEC would be favorable other than series connection of smaller ones, which can save cost, though the corresponding flow channel design is lacked. Herein, a “leaf‐vein” bionic flow channel for large‐scale PEMEC (the activation area is 1350 cm2) is proposed. A 3D mixture and steady model of the PEMEC is developed to characterize the two‐phase flow in the flow field. Detailed analyses of geometric parameters are conducted through orthogonal test to determine the optimal channel geometry. The numerical results show that the optimized design of PEMEC increases medium and low oxygen gas content, and reduces pressure drop compared to traditional flow channels. An interdigitated leaf‐vein flow field is applied, which effectively alleviates gas blockage problems. This article will provide a theoretical basis for large‐scale PEMEC manufacturing.

Exergoeconomic evaluation and multi-objective optimization of a novel geothermal-driven zero-emission system for cooling, electricity, and hydrogen production: capable of working with low-temperature resources

Geothermal energy is an abundant natural resource in many regions around the world. However, in some areas, the temperature of the geothermal energy resource is too low to be efficiently harvested. Organic Rankine cycles (ORCs) are known for recovering heat from low-temperature resources and generating electricity. Furthermore, half-effect absorption chillers (HEACs) are designed to produce cooling with low-temperature resources. This study proposes a novel configuration that utilizes an ORC for electricity generation, a HEAC for cooling production, and a PEM electrolysis system to produce hydrogen. The power section consists of two turbines, one driven by the vapor produced from the geothermal flow expansion, which powers the PEM section, while the other turbine in the ORC is used to drive pumps and electricity production. First, the system is thermoeconomically analyzed for an initial set of inputs. Then, various parameters are analyzed to determine their influences on system performance. The analyses reveal that the system can work with geothermal source temperatures as low as 80 °C, but the exergy and energy (thermal) efficiencies decrease to around 17% under the base settings. Furthermore, the system is capable of working with resource temperatures up to 170 °C. Ten parameters are found to affect the system’s efficiency and effectiveness. To optimize the system, the Non-dominated Sorting Genetic Algorithm II (NSGA-II) is implemented to find the optimum conditions. The objective functions are exergy efficiency and unit polygeneration cost (UPGC), which can conflict. The optimization shows that the exergy efficiency of the system can reach 48% in the optimal conditions (for a heat source temperature of 112 °C and a mass flow rate of geothermal fluid of 44 kg/s), with a hydrogen production rate of 1.1 kg/h.

Metallic Ru─Ru Interaction in Ruthenium Oxide Enabling Durable Proton Exchange Membrane Water Electrolysis.

Developing efficient and robust electrocatalysts toward the oxygen evolution reaction (OER) is critical for proton exchange membrane water electrolysis (PEMWE). RuO2 possesses intrinsically high OER activity, but the concurrent electrochemical dissolution leads to rapid deactivation. Here a unique RuO2 catalyst containing metallic Ru─Ru interactions (m-RuO2) is reported, which maintains stability in practical PEMWE for 100h at 60 °C and 1 A cm-2. Experimental and theoretical investigations suggest that the presence of Ru─Ru interactions significantly increases the energy barrier for the formation of RuO2(OH)2, which is a key intermediate for Ru dissolution, and hence substantially mitigates the electrochemical corrosion of m-RuO2. Meanwhile, the Ru4d band center downshifts, accordingly, ensuring the high OER activity, and the participation of lattice oxygen in the OER is also suppressed at the Ru─Ru sites, further contributing to the enhanced durability. Interestingly, such enhanced stability is also dependent on the size of metallic Ru─Ru cluster, where the energy barrier is further increased for Ru3, but is decreased for Ru5. These results highlight the significance of local coordination structure modulation on the electrochemical stability of RuO2 and open a feasible avenue toward the development of robust OER electrocatalysts for high-performance PEMWE.

Integrated assessment of green hydrogen production in California: Life cycle Greenhouse gas Emissions, Techno-Economic Feasibility, and resource variability

This study explores green hydrogen production, focusing on life cycle assessment (LCA) and techno-economic feasibility; specifically, life cycle greenhouse gas emissions and hydrogen production cost. Existing literature lacks a comprehensive exploration of the impact of solar and wind resource variations, ambient conditions, and proton exchange membrane (PEM) electrolyzer sizing on the carbon intensity (CI) and hydrogen production cost. This work explores the relationship between the performance of photovoltaic (PV) and wind systems and the CI of renewable electricity in the U.S. Secondly, this study incorporates the hourly variations in solar and wind resources to assess the variation in hydrogen CI and production costs across California. The study examines how reductions in PEM and Renewable Energy Systems (RES) costs, technological advancements, and the inclusion of co-products’ carbon dioxide equivalent (CO2eq) credits and revenues impact hydrogen CI and production costs. Wind-based systems consistently demonstrate lower CI (0.35 − 1.9 kg CO2eq/kg H2) except for the central regions (CI can reach up to 4.34 kg CO2eq/kg H2), with geographical variations larger than solar-based systems (1.58 − 2.95 kg CO2eq/kg H2). Similar trends are observed for the hydrogen production cost which varies between 1.5 and 15 USD/kg H2 for wind-based systems and between 3.0 and 5.2 USD/kg H2 for the PV-based systems. This study highlights the importance of optimal sizing of PEM electrolyzer to maximize its utilization for hydrogen production and the use of hourly-based models to assess the CI and production costs of hydrogen. Additionally, the geographical variation in the renewable energy resources and the ambient conditions are important factors that affect the hydrogen cost and the CI of both renewable electricity and green hydrogen.

Bicontinuous RuO2 nanoreactors for acidic water oxidation

Improving activity and stability of Ruthenium (Ru)-based catalysts in acidic environments is eager to replace more expensive Iridium (Ir)-based materials as practical anode catalyst for proton-exchange membrane water electrolyzers (PEMWEs). Here, a bicontinuous nanoreactor composed of multiscale defective RuO2 nanomonomers (MD-RuO2-BN) is conceived and confirmed by three-dimensional tomograph reconstruction technology. The unique bicontinuous nanoreactor structure provides abundant active sites and rapid mass transfer capability through a cavity confinement effect. Besides, existing vacancies and grain boundaries endow MD-RuO2-BN with generous low-coordination Ru atoms and weakened Ru-O interaction, inhibiting the oxidation of lattice oxygen and dissolution of high-valence Ru. Consequently, in acidic media, the electron- and micro-structure synchronously optimized MD-RuO2-BN achieves hyper water oxidation activity (196 mV @ 10 mA cm−2) and an ultralow degradation rate of 1.2 mV h−1. A homemade PEMWE using MD-RuO2-BN as anode also conveys high water splitting performance (1.64 V @ 1 A cm−2). Theoretical calculations and in-situ Raman spectra further unveil the electronic structure of MD-RuO2-BN and the mechanism of water oxidation processes, rationalizing the enhanced performance by the synergistic effect of multiscale defects and protected active Ru sites.

Revealing the Role of the Ionomer at the Triple-Phase Boundary in a Proton-Exchange Membrane Water Electrolyzer.

In the anodic catalyst layer of a proton-exchange membrane (PEM) water electrolyzer, the triple-phase boundary (TPB) is mainly distributed on the surface of ultrafine iridium-based catalysts encapsulated by the ionomer within the catalyst-ionomer agglomerate. It is found that the ionomer at the TPB acts as a barrier to mass transport and a buffer for the bubble coverage during the oxygen evolution reaction (OER). The barrier effect can decrease the OER performance of the catalysts inside the agglomerate by ≤23%, while the buffer effect can separate the bubble evolution sites from the OER sites, turning the instant deactivation caused by the bubble coverage into a gradual performance loss caused by local water starvation. However, this local water starvation still deteriorates the catalyst performance because of the affinity of the ionomer surface for bubbles. Introducing additional transport paths into the agglomerate can reduce the barrier effect and regulate the bubble behavior, reducing the overpotential by 0.308 V at 5 A cm-2.

KIr4O8 Nanowires with Rich Hydroxyl Promote Oxygen Evolution Reaction in Proton Exchange Membrane Water Electrolyzer.

The sluggish kinetics for anodic oxygen evolution reaction (OER) and insufficient catalytic performance over the corresponding Ir-based catalysts are still enormous challenges in proton exchange membrane water electrolyzer (PEMWE). Herein, we report that KIr4O8 nanowires anode catalyst with more exposed active sites and rich hydroxyl achieves a current density of 1.0 A/cm2 at 1.68V and possesses excellent catalytic stability with 1230h in PEMWE. Combining in situ Raman spectroscopy and differential electrochemical mass spectroscopy results, we propose the modified adsorbate evolution mechanism that rich hydroxyl in the inherent structure of KIr4O8 nanowires directly participates in the catalytic process for favoring the OER. Density functional theory calculation results further suggest that the enhanced proximity between Ir (d) and O (p) band center in KIr4O8 can strengthen the covalence of Ir-O, facilitate the electron transfer between adsorbents and active sites, and decrease the energy barrier of rate-determining step from OH* to O* during the OER. This article is protected by copyright. All rights reserved.

Multi-aspect assessment of a novel geothermal-driven polygeneration arrangement using water electrolyzer, methanol synthesis unit, and Goswami cycle

Geothermal energy’s renewable nature with minimal emissions compared to fossil fuels has led to valuable polygeneration models in geothermal-rich regions, promoting energy sustainability. Key challenges include improving integrated structures due to these resources’ low/medium temperature nature and assessing the feasibility of producing essential products (e.g., hydrogen and methanol), typically produced in structures with substantial pollution. The proposed system’s innovations focus on reducing irreversibility through thermal integration, introducing a negative CO2 emission structure, and utilizing CO2 hydrogenation based on geothermal energy for methanol production. Hence, the system encompasses a geothermal power plant, a Goswami cycle, a direct hydrogenation methanol synthesis unit, and a proton exchange membrane electrolyzer. The findings show generating methanol at a rate of 0.85 kg/s, domestic hot water at a rate of 2.231 kg/s, chilled water at a rate of 3.931 kg/s, and electric power at a capacity of 21,530 kW. Hence, the system’s thermal, electrical, and exergy efficiencies are determined to be 7.54 %, 3.87 %, and 47 %, respectively. Furthermore, the sum unit cost of products and the levelized energy cost equal 0.0272 $/GJ and 0.17 $/kWh, correspondingly. Additionally, a net present value of 65.86 M$ and a total yearly cost of 37.52 M$ are the results of the economic assessment. The current research demonstrates a negative CO2 emission from an environmental standpoint. The attainment of negative CO2 emissions is due to using CO2 as input material in the system. Also, the system’s net present value surpasses the total annual cost by 1.75 times, mainly due to its ability to produce products like methanol, generating revenue to offset initial costs. The proposed system is ideal for geothermal energy sites near seawater, promoting environmental preservation by reducing pollutants. Finally, it is suggested that the system’s operation be optimized and an experiential setup be used for future research.

Defective Tungsten Oxides with Stacking Faults for Proton Exchange Membrane Green-Hydrogen Generation.

Defects can introduce atomic structural modulation and tailor performance of materials. Herein, it demonstrates that semiconductor WO3 with inert electrocatalytic behavior can be activated through defect-induced tensile strains. Structural characterizations reveal that when simply treated in Ar/H2 atmosphere, oxygen vacancies will generate in WO3 and cause defective structures. Stacking faults are found in defects, thus modulating electronic structure and transforming electrocatalytic-inert WO3 into highly active electrocatalysts. Density functional theory (DFT) calculations are performed to calculate *H adsorption energies on various WOx surfaces, revealing the oxygen vacancy composition and strain predicted to optimize the catalytic activity of hydrogen evolution reaction (HER). Such defective tungsten oxides can be integrated into commercial proton exchange membrane (PEM) electrolyser with comparable performance toward Pt-based PEM. This work demonstrates defective metal oxides as promising non-noble metal catalysts for commercial PEM green-hydrogen generation.

Advanced polymer electrolyte membrane water electrolysis for power to gas applications

Abstract Water electrolysis fed by renewable energy is the foremost technology to generate green hydrogen. Relevant challenges regard decrease of precious metal loadings and performance enhancement while maintaining cutting edge efficiency. Next generation electrolysers must provide dynamic behaviour to improve grid-balancing services and thus integrate with the grid the intermittent renewable energy sources. The HPEM2GAS project developed a low-cost optimised PEM electrolyser for grid management through both stack and balance of plant innovations.

Unique construction of hierarchical PANI–based nanofibrous network for boosting water electrolysis through highly efficient utilization of Pt nanocatalyst

Enhancing catalytic activity of Pt and designing rational structure of catalytic layer (CL) are effective strategies for improving the performance of proton exchange membrane water electrolysis (PEMWE) with lower Pt loading. Herein, a hierarchical nanostructured CL based on co–doped carbon, sulfonated polyaniline (PANI) nanofibrous network and Pt nanoparticles is constructed on carbon cloth by layer–by–layer in–situ growth method. The N/P/S co–doped carbon interlayer derived from PANI can promote the growth of sulfonated PANI nanofibers. The in–situ grown Pt nanoparticles is anchored by sulfonated PANI, achieving uniform and stable distribution as well as altered electronic structure for improved catalytic activity. The unique CL greatly improves the electrochemical surface area and provides interconnected pathways. The as–prepared cathode exhibits an overpotential of 23 mV at 10 mA cm−2, indicating excellent hydrogen evolution performance. Furthermore, the PEMWE device with above–mentioned cathode achieves an excellent performance of 1.771 V @ 2 A cm−2 with low Pt loading of 0.07 mg cm−2, which is comparable to that of the conventional cathode with 14 times higher Pt loading of 1 mg cm−2. Our strategy of designing hierarchical nanostructured CL provides a feasible approach to lower the consumption of Pt without performance loss for further industrialization of PEMWE.

A comprehensive study of parameters distribution in a short PEM water electrolyzer stack utilizing a full-scale multi-physics model

Proton exchange membrane (PEM) electrolyzer is regarded as one of the most promising technologies for hydrogen production. To meet the requirements of large-scale hydrogen production, PEM electrolyzer stack that composed by series units are necessary. However, the composition brings extra problems such as maldistribution from the manifold to each unit, which results in parameters differences among the units and further gives rise to stack degradation. In this study, a full-scale three-dimensional multi-physics model is developed to simulate a short PEM electrolyzer stack with four single electrolyzer units. All the electrolyzer components and connections (e.g. manifold) are included in the model, and the temperature distribution, liquid saturation, membrane water content and electrolyzer performance are investigated in detail. The results indicate that performance of each single electrolyzer decreases from the first to the last unit along the water flow direction. It is recommended that the inlet temperature of electrolyzer stack should not exceed 60°C. To ease the thermal management, the water supply mode for cathode side can obviously lower the stack temperature to a preferred range, and improve the temperature uniformity. This study provides a comprehensive understanding of the distribution behaviors inside the electrolyzer stack and guides the operating parameters optimization.

Exergetic life cycle assessment for green hydrogen production

Life cycle assessment (LCA) is a method for assessing the environmental impacts of products and processes. The life cycle inventory provides a measure of the quantitative throughput of a process, but it cannot measure the intrinsic quality of that throughput. Exergy is a measure of the quantity and quality of energy. When combining LCA and exergy analysis in an exergy-based life cycle assessment (ExLCA) a powerful tool for the quantification of resource efficiency can be established. This study performs a detailed bottom-up cradle-to-grave ExLCA based on cumulative exergy consumption and exergy analysis of the use phase for a state-of-the-art (SoA) and a future plant 5 MW proton exchange membrane (PEM) electrolyzer plant. Three scenarios are implemented, i.e. SoA plant operated in the German grid mix of 2018, SoA plant operated in a defossilized grid, and a future plant operated in a defossilized grid. In every scenario, more than 98 % of the resource demand originates from electricity generation alone and decreases significantly with renewable electricity operation. In plant construction, the anode catalyst material iridium causes approximately half of the resource demand and bears the largest lever for the resource reduction potential of the plant construction of 65 %.

Crystalline Phase Engineering to Modulate the Interfacial Interaction of the Ruthenium/Molybdenum Carbide for Acidic Hydrogen Evolution.

Ruthenium (Ru) is an ideal substitute to commercial Pt/C for the acidic hydrogen evolution reaction (HER), but it still suffers from undesirable activity due to the strong adsorption free energy of H* (ΔGH*). Herein, we propose crystalline phase engineering by loading Ru clusters on precisely prepared cubic and hexagonal molybdenum carbide (α-MoC/β-Mo2C) supports to modulate the interfacial interactions and achieve high HER activity. Advanced spectroscopies demonstrate that Ru on β-Mo2C shows a lower valence state and withdraws more electrons from the support than that of Ru on α-MoC, indicative of a strong interfacial interaction. Density functional theory reveals that the ΔGH* of Ru/β-Mo2C approaches 0 eV, illuminating an enhancement mechanism at the Ru/β-Mo2C interface. The resultant Ru/β-Mo2C exhibits an encouraging performance in a proton exchange membrane water electrolyzer with a low cell voltage (1.58 V@ 1.0 A cm-2) and long stability (500 h@ 1.0 A cm-2).

Optimizing Ionomer Distribution in Anode Catalyst Layer for Stable Proton Exchange Membrane Water Electrolysis.

The high cost of proton exchange membrane water electrolysis (PEMWE) originates from the usage of precious materials, insufficient efficiency, and lifetime. In this work, an important degradation mechanism of PEMWE caused by dynamics of ionomers over time in anode catalyst layer (ACL), which is a purely mechanical degradation of microstructure, is identified. Contrary to conventional understanding that the microstructure of ACL is static, the micropores are inclined to be occupied by ionomers due to the localized swelling/creep/migration, especially near the ACL/PTL (porous transport layer) interface, where they form transport channels of reactant/product couples. Consequently, the ACL with increased ionomers at PTL/ACL interface exhibit rapid and continuous degradation. In addition, a close correlation between the microstructure of ACL and the catalyst ink is discovered. Specifically, if more ionomers migrate to the top layer of the ink, more ionomers accumulate at the ACL/PEM interface, leaving fewer ionomers at the ACL/PTL interface. Therefore, the ionomer distribution in ACL is successfully optimized, which exhibits reduced ionomers at the ACL/PTL interface and enriches ionomers at the ACL/PEM interface, reducing the decay rate by a factor of three when operated at 2.0 A cm-2 and 80°C. The findings provide a general way to achieve low-cost hydrogen production.