Nickel single-atom catalysts anchored on heteroatom (X = B, N, P, and S)-doped graphdiyne for a highly efficient hydrogen evolution reaction

Abstract

Identifying efficient and low-cost electrocatalysts for the hydrogen evolution reaction (HER) is essential for renewable energy applications. In recent years, single-atom catalysts (SACs) anchored on graphdiyne (GDY) have attracted great interest as promising HER electrocatalysts. However, the introduction of heteroatoms on the catalyst surface alters its catalytic performance. Herein, we rationally designed nickel SACs (Ni/nX-GDY, n = 1–2) anchored on graphdiyne doped with four types of heteroatoms (X = B, N, P, and S) and explored their HER catalytic activity using density functional theory calculations. By doping different heteroatoms, twelve different catalyst configurations were obtained with nickel anchored on the nX-GDY substrate, and compared with P/S doping, B/N doping resulted in superior thermodynamic stability. By evaluating hydrogen adsorption free energy (ΔG_H*), four optimal HER models (2B55, 1N3, 1P4, and 1S4) were identified; especially, the N-doped 1N3 model at the acetylenic carbon site exhibited the best ΔG_H* value, close to zero (−0.004 eV), demonstrating Ni/1N3-GDY as the most efficient HER catalyst in this series. Furthermore, it is concluded that at zero overpotential, the Volmer–Tafel mechanism with electrochemical desorption acts as the rate-limiting step in Ni/1N3-GDY, surpassing the Volmer–Heyrovsky mechanism. This study not only offers valuable insights into the rational design and discovery of highly efficient GDY-based HER electrocatalysts, but also promotes the development of hydrogen energy technologies.