Boosting visible-light hydrogen evolution via d-band center engineering in an FeP/graphdiyne heterointerface

Abstract

Constructing heterointerfaces with a strong built-in electric field (IEF) is a promising strategy to enhance photocatalytic activity. Herein, we report a high-conductivity FeP/graphdiyne (GDY) heterointerface synthesized via electrostatic self-assembly, achieving a remarkable visible-light-driven hydrogen evolution rate of 3400.26 μmol g⁻¹ h⁻¹ at the optimal FeP/GDY ratio. The exceptional performance originates from the IEF-induced directional electron transfer from GDY to FeP, which significantly suppresses charge recombination. In situ X-ray photoelectron spectroscopy (in situ XPS), electron paramagnetic resonance (EPR), and Kelvin probe force microscopy (KPFM) analyses confirm the interfacial charge redistribution, while charge density difference calculations reveal the driving force of electron migration. Furthermore, density functional theory (DFT) calculations demonstrate that the charge redistribution at the ohmic heterointerface optimizes the d-band center position of Fe sites, simultaneously weakening H* adsorption free energy and promoting H₂ desorption. This work provides a novel strategy for regulating d-band centers through interfacial electric field engineering.