In situ integration of cobalt diselenide nanoparticles on CNTs realizing durable hydrogen evolution.

Cobalt diselenide (CoSe 2 ) is considered to be a promising economical and efficient electrocatalyst for the hydrogen evolution reaction (HER). Here carbon nanotubes (CNTs) were employed as a conductive skeleton to optimize the electrocatalytic performance of CoSe 2 through a simple one-step hydrothermal method. Beyond the expected, the introduction of CNTs not only accelerates electron transportation and ion diffusion, but also improves the reaction kinetics for HER by forming a CoSe 2 /CNT heterointerface. Consequently, the CoSe 2 /CNTs composite exhibits an optimal overpotential of 153 mV with a weight ratio of 10 : 1, and sustains a long period of 48 hours with an negligible overpotential deterioration. In addition, a Faraday efficiency of 97.67% is achieved with a H 2 /O 2 molar ratio of 2 : 1. Therefore, these results open up further opportunities for yielding efficient and durable hydrogen evolving electrocatalysts from low-cost transition metal compounds.