Beyond the Oxygen Evolution Reaction: A Review of Electrocatalytic Hydrogen Generation Coupled with Small Molecule Oxidation

Driven by the rapid decline in renewable energy generation costs and the “dual carbon” goals, electrocatalytic water splitting powered by renewable electricity is increasingly becoming a vital method for producing high-purity hydrogen. However, the sluggish kinetics of the anodic four-electron oxygen evolution reaction(OER) significantly limit the overall energy efficiency of the process. By replacing conventional OER small molecule oxidation reactions that have lower thermodynamic barriers, low-energy- hydrogen production can be achieved, while simultaneously enabling the generation of high-value-added chemicals at the anode or the degradation and resource recovery of pollutants. Recent advances in coupled systems for electrocatalytic hydrogen evolution and organic/inorganic small molecule oxidation reactions are summarized, with a focus on catalyst design strategies, structure-activity relationships, and catalytic mechanisms under different alternative reaction pathways. Finally, future research directions and key challenges in this field are discussed, providing insights for advancing efficient and economical large-scale green hydrogen production.