Synergistic effect of graphdiyne (C2H2n-2) based hollow spherical Cu2O/GDY and NiS dual cocatalysts boosting photocatalytic hydrogen evolution

Abstract

The control of carrier separation morphology and efficiency is a key strategy for preparing high-performance photocatalysts. In this study, Cu₂O/graphdiyne was introduced into NiS in the form of hollow nanospheres, creating a novel composite material. This method improved upon the traditional graphdiyne fabrication processes that typically use copper foil. Through the hollow spherical structure, both internal and external surface light scattering and reflection were significantly enhanced, indirectly enhancing the light absorption rate of the photocatalyst and photocatalytic activity. Ultraviolet-visible spectroscopy and photoelectrochemical results showed that using NiS as the external cocatalyst and Cu₂O as the internal cocatalyst are the driving factors for the hydrogen evolution reaction, with a synergistic effect that accelerated the reaction. Such synergistic catalytic effects are rare in traditional photocatalytic systems, indicating their potential application value in enhancing catalytic efficiency. The overall performance was more than 22 times that of Cu₂O/graphdiyne alone and more than 2.6 times that of NiS. Additionally, the electronic band structures and reaction mechanisms can be elucidated through Density Functional Theory (DFT) calculations, Ultraviolet Photoelectron Spectroscopy (UPS) and UV-Vis spectroscopy. These findings not only offer practical guidance but also underscore the significance of precisely manipulating the components of composite catalysts to optimize performance.