Cobalt doping of FePS3 promotes intrinsic active sites for the efficient hydrogen evolution reaction.

Exploring Earth-abundant electrocatalysts to achieve the efficient hydrogen evolution reaction (HER) is important for the development of clean and renewable hydrogen energy. Herein, we focus on a representative transition metal phosphosulfide electrocatalyst FePS3. Enlightened by our theoretical calculations that Co dopants improve H affinity on P sites and electrical conductivity, we prepared a series of Fe1-xCoxPS3 (x = 0, 0.05, 0.1, 0.15, 0.2, 0.25) compounds and characterized them by XRD, ICP, XPS, Raman, SEM, TEM, EDS, and resistivity and electrochemical measurement. It is found that the overpotential can be reduced by 166 mV, and the Tafel slope drops from 170 mV dec-1 to 80 mV dec-1. This work provides new insights to optimize the electrocatalytic hydrogen evolution activity of related transition metal phosphosulfides.