Recent progress in transition-metal-oxide-based electrocatalysts for the oxygen evolution reaction in natural seawater splitting: A critical review

Direct electrolytic splitting of seawater for the production of H2 using ocean energy is a promising technology that can help achieve carbon neutrality.However,owing to the high concentrations of chlorine ions in seawater,the chlorine evolution reaction always competes with the oxygen evolution reaction(OER)at the anode,and chloride corrosion occurs on both the anode and cathode.Thus,effective electrocatalysts with high selectivity toward the OER and excellent resistance to chloride corrosion should be developed.In this critical review,we focus on the prospects of state-of-the-art metal-oxide electrocatalysts,including noble metal oxides,non-noble metal oxides and their compounds,and spinel-and perovskite-type oxides,for seawater splitting.We elucidate their chemical properties,excellent OER selectivity,outstanding anti-chlorine-corrosion performance,and reaction mechanisms.In particular,we review metal oxides that operate at high current densities,near industrial application levels,based on special catalyst design strategies.

High entropy materials based electrocatalysts for water splitting:Synthesis strategies,catalytic mechanisms,and prospects

Among various electrocatalysts,high entropy materials(HEMs)have attracted great attention due to the distinctive designing concept and unique properties with captivating electrocatalytic activity and stability.To date,HEMs have been a new family of advanced electrocatalysts in the research field of water electrolysis.In this work,the structural features and synthesis strategies of high entropy catalysts are reviewed,especially,their performances for catalyzing hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)in water electrolysis are presented,in which the crucial roles of structure,composition,multisites synergy,and“four core effects”for enhancing catalytic activity,stability,and resistance of electrochemical corrosion are introduced.Besides,the design tactics,main challenges,and future prospects of HEM-based electrocatalysts for HER and OER are discussed.It is expected to provide valuable information for the development of low-cost efficient HEM-based electrocatalysts in the field of water electrolysis.

Electrocatalytic seawater splitting for hydrogen production:Recent progress and future prospects

Earth-abundant seawater resource has become an attractive candidate to produce hydrogen from electrolysis,which is of great significance to realize hydrogen economy and carbon neutrality.Nonetheless,developing highly active and stable electrocatalysts to meet the needs of highly effective seawater splitting is still challenging for the sluggish oxygen evolution dynamics and the existed competitive reaction of chlorine evolution reaction(CER).To this end,some newly-developed electrocatalysts with superior performance,such as noble metals,alloy,transition metals,oxides,carbides,nitrides,phosphides,and so on,have been synthesized for the seawater splitting in recent years.This review starts from the historical background and fundamental mechanisms,and summarizes the most recent progress in the development of seawater electrolysis technologies.Some existing issues in the process of seawater electrolysis are enumerated and the corresponded solutions are presented.The future of hydrogen production from seawater electrolysis,especially the design and synthesis of novel catalysts for seawater electrolysis,is prospected.