Exploring single atom catalysts of transition-metal doped phosphorus carbide monolayer for HER: A first-principles study

Abstract

• The single Ir atom doped α-PC has much smaller Gibbs free adsorption energy of H atom comparing to the reported Pt(111). • The Gibbs free adsorption energy of H atom is highly related to the d-band center and the period of the doped TM atom. • The Volmer–Heyrovsky step has smaller energy barrier than the Volmer-Tafel step on Ir-αPC. • The Ir-PC is physically and thermally stable according to phonon calculation and AIMD result. Hydrogen has been identified as one of the most promising sustainable and clean energy. Developing hydrogen evolution reaction (HER) catalyst with high activity is essential for satisfying the future requirements. Considering novel advantages of two-dimensional materials and high catalytic activity of atomic transition metal, in this study, using density functional theory calculation, the HER on single transition-metal (23 different TM atoms) doped phosphorus carbide monolayer (α-PC) has been investigated. The Volmer–Tafel and Volmer–Heyrovsky reaction mechanisms, and the stability of the most promising HER catalyst are also included. The results show that Ir-αPC with high physical and thermal stability has the most optimal value of Gibbs free adsorption energy for H atom. The relationship of d band center and the HER activity shows a volcano-like curve. The calculation of reaction energy barrier indicates that the Volmer-Heyrovsky step is more favorable than the Volmer-Tafel step.