Interface and heteroatom engineering in graphene/g-C₃N₄ heterostructures: a pathway to high-efficiency metal-free catalysts for hydrogen evolution reaction

Abstract As a clean and sustainable energy source, hydrogen is expected to play a crucial role in addressing excessive carbon dioxide emissions and the depletion of fossil fuels. Herein, by means of density functional theory computations, we have systematically investigated the effects of interface engineering in a series of graphene/g-C 3 N 4 (G/g-C 3 N 4 ) with heteroatom doping (X-G/g-C 3 N 4 and G/X-g-C 3 N 4 , X = B, N, Si, P and S) on hydrogen evolution reaction (HER) catalytic performance. Our results reveal that these X-doped G/g-C 3 N 4 interfaces exhibit excellent stability, enhanced metallic features, terrific mechanic properties, and exceptional magnetic properties. Remarkably, through precise regulation of the positioning of Si or P heteroatom, X-G/g-C 3 N 4 interfaces demonstrate outstanding excellent catalytic performance, characterized by hydrogen adsorption free energy ( ΔG H* ) values approaching zero, which can be ascribed to its appropriately positioned p-band centers near the Fermi level. This work provides valuable insights for the rational design of HER catalysts aimed at sustainable high-purity H 2 production.