Recent advances in green hydrogen production by electrolyzing water with anion-exchange membrane

Background

The development of clean and efficient renewable energy is a key strategy for achieving green energy transition and low-carbon growth. As an ideal "zero-carbon" energy carrier, hydrogen can be efficiently converted into hydrogen energy and electricity through water electrolysis technology, playing a vital role in the carbon neutrality process. Among various technologies, anion exchange membrane water electrolysis (AEMWE) has emerged as a major research focus due to its significant cost advantages and commercialization potential. By utilizing non-precious metal electrocatalysts, AEMWE successfully combines the high efficiency of proton exchange membranes with the mature process advantages of conventional alkaline electrolysis, while potentially overcoming their respective technical limitations, demonstrating broad application prospects.

Research Progress

The industrialization of AEMWE technology is primarily constrained by the kinetic performance of two core electrochemical reactions—the anodic oxygen evolution reaction (OER) and the cathodic hydrogen evolution reaction (HER). In particular, the development and structural innovation of low-cost, abundant transition metal catalysts (such as Ni, Fe, and Co) aim to enhance catalytic efficiency through alloying and co-doping, thereby accelerating technological progress. Among these, the OER reaction faces a significant challenge due to its high thermodynamic energy barrier (237 kJ mol⁻¹) and multi-step electron-proton coupled transfer process. The sluggish reaction kinetics necessitate a higher overpotential to achieve industrial-scale current density, making it the key bottleneck limiting the overall efficiency of water electrolysis systems. This technical hurdle has made the development of highly active and stable non-precious metal OER catalysts a major research focus.

For instance, we employed a polyoxometalate (POM)-assisted wet-etching method to reconstruct nickel-iron layered double hydroxide (NiFe LDH), achieving three-dimensional morphological tailoring, active species reconstruction, defect introduction, and POM polyanion intercalation. These structural and chemical optimizations significantly enhanced the OER performance of the catalyst, demonstrating a low overpotential (206 mV@10 mA cm⁻²) and excellent stability (no significant decay over 24 hours) under alkaline conditions. Furthermore, the study proposed an empirical formula to quantitatively analyze the structure-activity relationship, providing new theoretical guidance for designing efficient OER catalysts. These advancements are expected to drive the development of AEMWE technology.

Meanwhile, although the HER reaction has a lower thermodynamic barrier, its kinetic process still presents challenges in practical operations, particularly at high current densities where the activity and stability of catalysts are crucial. Huang Huawei et al. developed a novel nanoheterostructured cathode catalyst (Ni₃N@W₅N₄) consisting of Ni₃N nanoparticles encapsulated by an ultrathin W₅N₄ shell. The built-in interfacial electric field (BIEF), originating from the distinct lattice arrangements and work functions of the dual-phase metal nitrides, promotes interfacial electron localization, significantly reducing the energy barrier of the rate-determining step (RDS) from 1.40 eV to 0.26 eV. This catalyst demonstrates exceptional alkaline HER performance (60 mV@10 mA cm⁻²) and long-term stability (100 hours at 500 mA cm⁻²). When applied as a cathode in AEMWE devices, it enables stable operation for over 80 hours at 1 A cm⁻² current density. This breakthrough provides critical technical support for advancing the industrialization of anion exchange membrane water electrolysis technology, contributing to reduced hydrogen production costs and enhanced overall system performance.

Future Prospects

In the future, the development of AEMWE technology will focus on efficiency improvement and stability breakthroughs to accelerate its application in the large-scale production of green hydrogen. Key technological breakthroughs include: first, the development of new anion-exchange membrane materials, through the design of molecular structure to achieve high ionic conductivity, excellent chemical stability and mechanical strength of the synergistic optimization, so as to reduce the membrane resistance and prolong the service life; second, the design of high-efficiency nonprecious metal catalysts, combined with theoretical simulation and experimental validation, the use of nano-structure regulation, alloying strategies to improve the density of the HER/OER active sites and reaction kinetics; third, the optimization of the system integration technology, through the electrode-membrane interface engineering, three-dimensional structure and stability, to accelerate the application of green hydrogen scale production. The third is to optimize the system integration technology, and to improve the energy efficiency and operational stability of the equipment through electrode-membrane interface engineering, three-dimensional flow field design and other innovations. At the same time, a standardized testing system and long-term evaluation mechanism are established to provide support for industrialization. With the cost reduction brought by material innovation and process improvement, AEMWE technology is expected to become an important pillar of the green hydrogen economy and provide key technological solutions for the global energy transition. Translation

Author's Profile

Prof.Dr. Jiangwei Zhang is currently a "Steed plan High level Talents" Professor, "Grassland Talents", "Inner Mongolia Rejuvenation Talents" of Inner Mongolia, Principle Investigator from College of Energy Material and Chemistry under leadership of Dean Academician Dongyuan Zhao, Inner Mongolia University. He received his Ph.D. from Department of Chemistry, Tsinghua University in 2016. He has published 206 innovative publications including in Science;Research; Nat. Catal.; JACS; Adv. Mater.; Angew.; Nat. Commun.; EES as corresponding author with H-index=55. He is selected as World’s Top 2% Scientists in 2024. Currently, his researches fuscous on the common key scientific issues "materials structure and reaction mechanism dynamically and precisely visual detection and determination"; "Advanced characterization methodology and energy catalytic materials Interdisciplinary"; "water electrolysis hydrogen production electrolyzing material and cell".

Sources: https://spj.science.org/doi/10.34133/research.0677