Spontaneous charge redistribution with diverse nucleophilic and electrophilic sites in NiTe/Mo6Te8 for urea-assisted water electrolysis

Abstract

Developing heterojunction catalysts with diverse adsorption sites presents significant opportunities to enhance the performance of urea-assisted water electrolysis. Herein, we highlighted a NiTe/Mo₆Te₈ heterojunction catalyst confined in carbon nanofiber with spontaneous charge redistribution driven by high valent metal, which promotes the adsorption and transformation of intermediates and greatly reduces the reaction energy barrier for urea oxidation. The heterojunction catalyst promotes the formation of Ni³⁺ active species and accelerates the fracture of the C–N bond by enhancing selective adsorption of –NH₂ and C=O groups in binding urea molecules driven by the spontaneous formation of nucleophilic and electrophilic sites. The catalyst achieves a low kinetic current density of 10 mA cm⁻² at 1.35 V with a cell voltage for urea electrolysis of just 1.47 V and good durability over 60 h. Density-functional theory and in-situ spectral observation reveal that the high valent Mo promoted the 3d orbit of Ni approaching the Fermi level by adjusting the electronic structure, which enhanced spontaneous urea dehydrogenation and reduced the energy barrier for *COO desorption. This study highlights the effectiveness of modulating the interfacial electronic structure to improve energy conversion efficiency.