Interfacial engineering of NiMn-LDH@Rh(OH)3 Heterojunctions for Promoted electrocatalytic urea oxidation

Abstract

The urea oxidation reaction (UOR) is considered as an alternative to the oxygen evolution reaction for high-efficiency hydrogen production, because it can simultaneously achieve wastewater treatment and hydrogen production. However, the slow kinetics of the UOR hinder its widespread adoption due to relatively complex molecule, it is urgent to rational design and preparation of high-performance UOR catalysts. Herein, we report a simple synthesis of the NiMn-LDH@Rh(OH)₃ heterostructure and a systematic investigation of urea-assisted electrolytic hydrogen production， significantly enhances the efficiency of urea electrolysis. The amorphous Rh(OH)₃ structure provides a higher density of active sites and greater catalytic surface exposure, while the synergistic interaction between Rh(OH)₃ and NiMn-LDH improves both electrical conductivity and catalytic performance. The catalyst of NiMn-LDH@Rh(OH)₃–3 requires only 1.29 V overpotential to achieve a current density of 10 mA cm⁻² in a 1.0 M KOH and 0.33 M urea solution, surpassing other catalysts. Furthermore, it demonstrates remarkable stability with minimal potential increase during 48-hour chronopotentiometric tests at 100 mA cm⁻². This work making the developed strategy promising for the rational design of highly active electrocatalysts for green hydrogen production and the treatment of urea-rich wastewater.