A Highly Active and Stable Electrocatalyst Based on Nicos Nano-Flower Structure for Hydrogen Evolution Reaction

Developments of high and efficient electrocatalyst are significant attentions for the hydrogen evolution reaction. Platinum metal group and its alloys represent the most efficient catalytic activity for hydrogen evolution reaction (HER). However, the high cost and low abundant of Pt metal impede their commercial scale-up application. To solve these problems, the transition-metal based catalysts are developing to alter Pt-based catalysts. In this work, we used carbon dot (C-dot) as a structure-directing agent to first synthesize NiCoOH nano-flower, and then, sulfur atomss were solvothermally dopped into the NiCoOH nano-flower to generate the NiCoS nano-flower. The NiCoS nano-flower structure shows an onset potential of 90 mV, and an overpotential of 232 mV at a current density of 10 mA cm −2 and a Tafel slope of 80.17 mV dec −1 . Furthermore, the Rct value of the NiCoS is 63.3 Ω. Especially, as-prepared catalyst shows an excellent long-term durability, which was confirmed by chronopotentionmetric response for 20 hours to maintain current densities at 10 mA cm −2 . Therefore, this catalyst can be considered as a promising candidate for hydrogen production.