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

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.

Automated summary

In this study, a novel strategy of N-doping induced phase transfer was proposed to construct anomalous metastable hcp-CoNi-N/C material for urea oxidation reaction (UOR). The hcp-CoNi-N/C exhibited impressive UOR performance with a low potential of 1.310 V vs. RHE to achieve 10 mA cm-2 and fast reaction kinetics. The unconventional hcp phase design coupled with metal and non-metal dual doping engineering enabled electron density manipulation, charge-polarized surface, and improved mass transfer kinetics.