Mediating Self‐Oxidation and Competitive Adsorption for Achieving High‐Selective Urea Oxidation Catalysis at Industrial‐Level Current Densities

Abstract

Inhibiting the deactivation of nickel‐based catalysts caused by self‐oxidation and competitive adsorption behavior is still a major challenge for urea oxidation reaction (UOR), especially under industrial‐level current densities. In this study, a crystalline NiSe2/amorphous NiFe‐LDH (NiSe2/NiFe‐LDH) heterojunction catalyst is rationally constructed for selective electrocatalytic UOR. In situ Raman spectra and ex situ characterization results reveal that such a structure can tailor the self‐oxidation of catalyst and impede the accumulation of NiOOH species during the UOR process. Density function theory simulations disclose that the self‐driven charge transport from electron‐deficient NiFe‐LDH region to electron‐rich NiSe2 region would induce the formation of local electrophilic/nucleophilic region to adsorb the electron‐donating ‐NH2 and electron‐withdrawing C = O groups, respectively. This optimizes the adsorption of urea molecules and hinders the overaccumulation of OH− ions on the surface of NiSe2/NiFe‐LDH, which is beneficial for the priority occurrence of UOR over the oxygen evolution reaction (OER) and the realization of high UOR selectivity. Benefiting from the tailored surface self‐oxidation and favorable urea adsorption, the NiSe2/NiFe‐LDH could act as a high‐selective UOR anode and achieve ultrahigh 800 mAcm−2 only at 1.447 V. Besides, UV–vis spectrophotometry also unveiled that the NiSe2/NiFe‐LDH has the capability to electrochemically degrade urea, offering great promise for practical application potentials.