Energy-saving electrochemical hydrogen production via co-generative strategies in hybrid water electrolysis: Recent advances and perspectives

With the increase of global energy demand and environmental pollution, the development of sustainable energy to reduce the consumption of fossil fuels (such as oil, natural gas and coal) has become the key to achieve sustainable development of human society. Hydrogen energy is considered as the most ideal alternative energy because of its high energy density, pollution-free combustion, and various application forms.

Hydrogen production from water splitting includes cathodic hydrogen evolution reaction (HER) and anodic oxygen evolution reaction (OER), which has the characteristics of green environmental protection, flexible production, and high purity, and is one of the ideal green production technologies. However, the intrinsic slow kinetics of the anodic oxygen evolution reaction severely results in low hydrogen production efficiency of cathode. In addition, during the process of water electrolysis, highly oxidizing hydrogen peroxide (H₂O₂) will be produced, reducing the life of the film for electrolytic water and hindering the practical application of electrolytic water technology. Therefore, it is urgent to develop new high-efficiency, stable and high value-added electrolytic water catalysts.

The hybrid water electrolysis (HWE) configuration that combines thermodynamically favorable oxidation reaction processes at the anode and HER at the cathode comes into the spot as a particularly attractive alternative to maximize H₂ production. More importantly, substituting the sluggish OER process with thermodynamically more favorable oxidation reactions affords ground-breaking for enriching highly efficient energy-saving H₂ production, meanwhile enabling additional functionalities such as purifying industrial wastewater and creating high-value-added chemical. Hence, it is requisite to nominate suitable synergistic electrocatalysis configurations based on electrochemical precepts of electro-coupled catalytic processes.

Recently, a research team led by Prof. Qinfang Zhang from Yancheng Institute of Technology, China, reviewed some key guidelines for the discovery of efficient multi-functional hybrid water electrolysis (HWE) systems for co-generation of energy-saving H₂ and high value-added products. An overview of HWE system is presented first accompanied by a discussion on the design and engineering of high reactive/selective/stable electrodes/electrocatalysts for anodic oxidation of organic/biomass substrates. The in-depth understanding of possible reaction mechanisms from both experimental and theoretical perspectives is elucidated to promote the efficiency of synergistic electrocatalysis. The recent research breakthroughs in the field of HWE technology are emphatically reviewed, providing a new room for low-voltage H₂ generation from waste products and renewable feedstock. Proposing the prospects on existing challenges with some opportunities for future research directions is also presented in this work. The results were published in Chinese Journal of Catalysis (https://doi.org/10.1016/S1872-2067(23)64544-9).

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About the Journal

Chinese Journal of Catalysis is co-sponsored by Dalian Institute of Chemical Physics, Chinese Academy of Sciences and Chinese Chemical Society, and it is currently published by Elsevier group. This monthly journal publishes in English timely contributions of original and rigorously reviewed manuscripts covering all areas of catalysis. The journal publishes Reviews, Accounts, Communications, Articles, Highlights, Perspectives, and Viewpoints of highly scientific values that help understanding and defining of new concepts in both fundamental issues and practical applications of catalysis. Chinese Journal of Catalysis ranks among the top one journals in Applied Chemistry with a current SCI impact factor of 16.5. The Editors-in-Chief are Profs. Can Li and Tao Zhang.

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