Mutual promotion effect of Ni and Mo2C encapsulated in N-doped porous carbon on bifunctional overall urea oxidation catalysis

Abstract

Efficient hydrogen production from water splitting is crucial for sustainable energy and yet impeded by sluggish anodic water oxidation. Urea oxidation had been considered as an alternative reaction due to its much lower oxidation potential. Rational design of highly efficient cost-effective electrocatalysts for urea oxidation is therefore urgent for hydrogen production from overall urea oxidation. Here, the Ni/Mo2C@CN catalyst consisting of a porous carbon shell and a heterojunction Ni/Mo2C core was constructed by an in situ self-confinement synthesis strategy. The mutual promotion effect of Ni and Mo2C can boost the urea oxidation and hydrogen evolution reactions at the same time. Only 1.51 V applied potential was needed to achieve stable 10 mA/cm2 overall urea oxidation on the Ni/Mo2C@CN catalyst. By considering the great stability resulting from the protective effect of the carbon shell, a practical application potential of Ni/Mo2C@CN in overall urea oxidation was achieved.