Nitrogen‐Doped CoP Electrocatalysts for Coupled Hydrogen Evolution and Sulfur Generation with Low Energy Consumption

Hydrogen production is the key step for the future hydrogen economy. As a promising H2 production route, electrolysis of water suffers from high overpotentials and high energy consumption. This study proposes an N‐doped CoP as the novel and effective electrocatalyst for hydrogen evolution reaction (HER) and constructs a coupled system for simultaneous hydrogen and sulfur production. Nitrogen doping lowers the d‐band of CoP and weakens the H adsorption on the surface of CoP because of the strong electronegativity of nitrogen as compared to phosphorus. The H adsorption that is close to thermos‐neutral states enables the effective electrolysis of the HER. Only −42 mV is required to drive a current density of −10 mA cm−2 for the HER. The oxygen evolution reaction in the anode is replaced by the oxidation reaction of Fe2+, which is regenerated by a coupled H2S absorption reaction. The coupled system can significantly reduce the energy consumption of the HER and recover useful sulfur sources. A highly active nitrogen‐doped CoP catalyst is developed to concurrently produce hydrogen gas and recover sulfur resources with low energy consumption by introducing Fe3+/Fe2+ redox mediators and hydrogen sulfide in a coupled system of electrolysis and absorption.