Interface Engineering of Graphdiyne (g-C n H 2n-2 ) coupling with NiCoP for Constructing a Barrier-Free Electron Channel in Photocatalytic Hydrogen Evolution

Abstract

The core challenge of developing an efficient photocatalytic hydrogen evolution system is how to achieve efficient separation and rapid migration of photogenerated carriers. In this study, a composite photocatalyst based on atomically ordered Fe 2 P-type NiCoP and graphdiyne (GDY) was successfully constructed to explore its photocatalytic hydrogen evolution activity, and the key mechanism of forming an efficient ohmic junction at its interface was revealed for the first time. Among the prepared catalysts, the 15% NiCoP/GDY composite showed enhanced activity with a hydrogen evolution rate of 4457.6 μmol•h⁻¹•g⁻¹, being 15 times and 4 times higher than that of pure GDY and NiCoP, respectively. The theoretical calculation of the density of states shows that the metal-like properties of NiCoP are aligned with the energy band of GDY at the Fermi level, forming a barrier-free ohmic contact and constructing an efficient electron transfer channel. The sharp shortening of the carrier lifetime (τ 2 ) in the femtosecond transient spectrum directly confirms the ultrafast injection process of photogenerated electrons from GDY to NiCoP. Thanks to this, the composite material achieves near-extreme interfacial charge separation, synergistic effect with the high intrinsic activity of NiCoP, and ultimately drives excellent photocatalytic hydrogen evolution performance. This work provides a new paradigm for designing GDY-based ohmic junction efficient photocatalysts through interface engineering.