Reducing Energy Costs during Hydrogen Production from Water Electrolysis by Coupling Small Molecule Oxidation: From Molecular Catalysis to Industrial Exploration.

Hydrogen energy has garnered significant attention in recent years as a solution to address the global energy crisis and environmental pollution. While water electrolysis stands out as the most promising method to produce green hydrogen, the sluggish reaction kinetics of the oxygen evolution reaction (OER) on the anode increases the cost of hydrogen production. One potential solution to this challenge is replace OER with the thermodynamically more favorable oxidation of small molecules, which can efficiently reduce the energy cost while simultaneously yielding high-value chemicals. Up to now, various organic oxidation reactions have been reported to couple with hydrogen evolution, including alcohol oxidation, biomass platform molecule upgrading, and sacrificial reagents oxidation associated with wastewater treatments. This review concentrates on the recent advancements in the mechanism, catalyst, reactor, and process in this field, with a discussion on its prospects for commercialization.