Bimetal Schottky Heterojunction Boosting Energy‐Saving Hydrogen Production from Alkaline Water via Urea Electrocatalysis

Hydrogen production via water electrocatalysis is limited by the sluggish anodic oxygen evolution reaction (OER) that requires a high overpotential. In response, a urea‐assisted energy‐saving alkaline hydrogen‐production system has been investigated by replacing OER with a more oxidizable urea oxidation reaction (UOR). A bimetal heterostructure CoMn/CoMn2O4 as a bifunctional catalyst is constructed in an alkaline system for both urea oxidation and hydrogen evolution reaction (HER). Based on the Schottky heterojunction structure, CoMn/CoMn2O4 induces self‐driven charge transfer at the interface, which facilitates the absorption of reactant molecules and the fracture of chemical bonds, therefore triggering the decomposition of water and urea. As a result, the heterostructured electrode exhibits ultralow potentials of −0.069 and 1.32 V (vs reversible hydrogen electrode) to reach 10 mA cm−2 for HER and UOR, respectively, in alkaline solution, and the full urea electrolysis driven by CoMn/CoMn2O4 delivers 10 mA cm−2 at a relatively low potential of 1.51 V and performs stably for more than 15 h. This represents a novel strategy of Mott–Schottky hybrids in electrocatalysts and should inspire the development of sustainable energy conversion by combining hydrogen production and sewage treatment. A Schottky catalyst is constructed from a CoMn/CoMn2O4 heterostructure for energy‐saving hydrogen production from alkaline solution via urea electrocatalysis. Benefiting from the interface electron redistribution, CoMn/CoMn2O4 can synergistically facilitate the adsorption and fracture of the chemical groups in urea and water molecules and thus promote urea electrocatalysis.