Interfacial Electronic Rearrangement and Synergistic Catalysis for Alkaline Water Splitting in Carbon Encapsulated Ni (111)/Ni3c (113) Heterostructure

Abstract

The realization of efficient water electrolysis is still blocked by the requirement of a high and stable driving potential above thermodynamic requirements. Here we tackle the challenge by tuning surface electronic structure synergistic with interfacial chemistry and crystal facet engineering, and successfully design and synthesize the carbon encapsulated Ni /Ni 3 C heterojunction electrocatalyst, demonstrating superior HER activities and good stabilities with a small overpotential of -29 mV at 10 mA/cm 2 , a low Tafel slope of 59.96 mV/dec in alkaline surroundings, nearing commercial Pt/C catalyst and outperforming other reported Ni-based catalysts. The heterostructure electrocatalyst operates at 1.55 V and 1.26 V to reach 10 and 1 mA cm - 2  in two-electrode measurements for alkaline overall water splitting, corresponding to 79% and 98% electricity-to-fuel conversion efficiency with respect to the lower heating value of hydrogen.

Keywords: Key words: Electrocatalyst, Nickel based materials, Built-in electric field, Overall water splitting