In situ -generated metallic nickel from hydrothermal-nitridation as an efficient platform for small-molecule electrooxidation

Abstract

Transition-metal hydroxides are promising electrocatalysts for small-molecule oxidation, yet their poor conductivity severely limits charge-transfer kinetics. Herein, we report the nitridation-induced metallization of semi-insulating NiNi3(OH)x into highly conductive metallic nickel (Ni0) via a hydrothermal ammonia treatment. This phase-engineering strategy substantially overcomes charge-transport bottlenecks. Consequently, the resulting catalyst achieves a high current density of 200 mA cm−2 at 1.35 V vs reversible hydrogen electrode for the ethanol oxidation reaction, significantly outperforming its precursor (1.43 V). Operando Raman spectroscopy reveals the accelerated formation of active NiOOH species, while mass spectrometry confirms a dominant C2 pathway yielding 97.5% acetate selectivity and 100 h stability. This strategy also enhances methanol and urea oxidation, offering a versatile platform for efficient small-molecule upgrading.