Interfacial Ni-Te Bond-Length Engineering Enables Selective Urea Oxidation for Sustainable Hydrogen Production and Nitrogen Recovery.

Abstract

Nickel-based catalysts are top candidates for urea oxidation-assisted H₂ production, enabling green energy and wastewater remediation. However, they suffer from NO_<i>x</i>^- formation and degradation due to uncontrolled urea peroxidation during the urea oxidation reaction (UOR). Here, we propose a bond-length engineering strategy for nickel telluride (NiTe) catalysts to modulate the interfacial electronic environment and suppress undesired urea peroxidation. With precise elongation of the Ni-Te bond from 2.49 Å to 2.71 Å, the NiTe catalyst shows asymmetric charge distribution and its d-band center shifts further away the Fermi level, thereby promoting OH^- adsorption at the electrode-electrolyte interface. This facilitates Ni³⁺-O layer formation, stabilizing the *H₂NCNO intermediate and enabling N≡N coupling while suppressing C-N bond cleavage. The catalyst reached 100 mA cm^-2 at 1.33 V vs RHE with high N₂ selectivity maintained even at 1.75 V vs RHE. A membrane electrode assembly using the optimized NiTe catalyst delivers 1000 mA cm^-2 at 1.55 V with >1250 h of stable operation and high N₂ Faradaic efficiency. Integrated into a photovoltaic-electrocatalysis system, it achieves 11.2 ± 0.6% STH efficiency and 9.39 mmol cm^-2 h^-1 H₂ output with >80% N₂ selectivity. This work offers a targeted design strategy for selective and durable UOR catalysts in sustainable hydrogen energy conversion systems.