Interface engineering of graphdiyne (g-CnH2n−2) coupled with NiCoP to construct a barrier-free electron channel for photocatalytic hydrogen evolution

Abstract

The core challenge of developing an efficient photocatalytic hydrogen evolution system is achieving efficient separation and rapid migration of photogenerated carriers. In this study, a composite photocatalyst based on atomically ordered Fe₂P-type NiCoP and graphdiyne (GDY) was successfully constructed to explore its photocatalytic hydrogen evolution activity, and the key mechanism for 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, which is 15 times and 4 times higher than that of pure GDY and NiCoP, respectively. 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 drastic shortening of the carrier lifetime (τ₂) in the femtosecond transient spectrum directly confirms the ultrafast injection process of photogenerated electrons from GDY to NiCoP. As a result, the composite material achieves near-extreme interfacial charge separation, synergistically combining with the high intrinsic activity of NiCoP to ultimately drive excellent photocatalytic hydrogen evolution performance. This work provides a new paradigm for designing efficient GDY-based Ohmic junction photocatalysts through interface engineering.