Unusual hcp Ni with metal and non-metal dual doping modulation to realize boosted urea oxidation

Abstract

Modulating cost-competitive metallic Ni-based electrocatalysts with favorable surface electronic configuration to boost urea oxidation reaction (UOR) is crucial to urea-related technologies, yet dauntingly challenging due to limited tailoring methods. Herein we put forward a novel N-doping induced phase transfer strategy to construct anomalous metastable hcp Ni with metal Co and non-metal N dual doping engineering (hcp-CoNi-N/C) for manipulating electronic state and catalytic response toward the UOR. Impressively, the hcp-CoNi-N/C can deliver prominent UOR performance with an exceptionally low potential of 1.310 V vs. RHE to attain 10 mA cm−2 and fast reaction kinetics (34.0 mV dec–1), standing out among the best UOR catalysts reported to date. The combined experimental analysis and theoretical calculations disclose that unconventional hcp phase design coupled with metal and non-metal dual doping engineering enables electron density manipulation and creates a charge-polarized surface favorable for urea adsorption and C–N bond cleavage, thereby substantially promoting urea decomposition. Meanwhile, such synergistic phase and doping engineering can boost mass transfer kinetics via tailoring the wetting characteristics. This study offers a new paradigm to craft advanced metallic Ni-based UOR catalysts through unusual metastable phase design synergistic with multiple doping engineering.