Heterojunction-Induced Local Charge Redistribution Boosting Energy-Saving Hydrogen Production via Urea Electrolysis

Substituting the oxygen evolution reaction by the urea oxidation reaction (UOR) is thermodynamically more favorable for energy-saving hydrogen production. However, UOR suffers from sluggish reaction kinetics due to its complex six-electron transfer processes combined with conversion of complicated intermediates. Herein, LaNiO3–NiO heterojunctions successfully constructed to accelerate UOR. Systematic experimental investigation and theoretical calculation endorse that self-driven local charge redistribution takes place at the Janus LaNiO3/NiO interface, generating local nucleophilic and electrophilic regions. Such a unique structure is favorable for targeted adsorption of amino groups and electrophilic carbonyl groups, thus promoting the rupture of C–N bonds in urea. In addition, the build-in electric field triggered by LaNiO3–NiO heterojunction could effectively diminish the stepwise energy barrier, accelerating desorption of *CO2. As a result, the LaNiO3–NiO exhibits superior UOR performance, delivering a current density of 10 mA cm–2 at 1.34 V (vs RHE). This work supplies valuable insights for fundamental understanding and rational construction of efficient heterojunction UOR catalyst.