First-Principles Study in Graphene-Based Single-Atom Catalysts for Hydrogen Evolution Reactions

Electrochemical water splitting is the most promising process for producing hydrogen as an energy carrier. The electrocatalysts, as the main step in hydrogen evolution reaction (HER) of water electrolysis, are crucial for reducing the energy barrier and improving reaction efficiency. This motivates us to design low-cost and highly active HER electrocatalysts. Herein, we utilize density functional theory (DFT) calculations to explore the HER activity on the surface of graphene doped with single atoms of copper, iron, and platinum, respectively. We explore the HER activity of graphene with two different doping sites, in-plane and out-of-plane. The absolute value of the hydrogen adsorption Gibbs free energy change of each sample are less than 1 eV, showing good hydrogen adsorption performance, which are close to the HER performance of noble metal catalysts. Meantime, electronic structure analysis shows that the energy of the bonding orbital of Fe in-plane site is greatly reduced, and the antibonding orbital is not filled with electrons.