Modulating the Volmer Step by MOF Derivatives Assembled with Heterogeneous Ni2P-CoP Nanocrystals in Alkaline Hydrogen Evolution Reaction

Developing efficient non-noble metal electrocatalysts for hydrogen evolution reaction (HER) in alkaline media is still a significant challenge. Sluggish kinetics of the Volmer step of water dissociation is a major cause. Herein, we demonstrate that the kinetics can be boosted by constructing abundant heterogeneous interfaces between nickel phosphide and cobalt phosphide nanocrystals. A nickel phosphide nanoparticles coated on cobalt phosphide nanoarrays nanostructure derived from metal-organic framework is rationally designed and synthesized on carbon cloth (Ni2P-CoP/CC). Electrochemical tests reveal that even under extremely alkaline concentration (1 M KOH), the Ni2P-CoP/CC exhibits excellent HER activity, with overpotentials of 74 and 120 mV at 10 and 100 mA cm(-2) respectively, and excellent stability of continuously working for more than 20 h. The electrochemical performance is better than most of cobalt phosphide-based catalysts and comparable to noble-metal benchmarks. This work opens up a new avenue for designing efficient alkaline HER electrocatalysts. (C) 2018 The Electrochemical Society.