Spatial positioning effect of dual cocatalysts accelerating charge transfer in three dimensionally ordered macroporous g-C₃N₄ for photocatalytic hydrogen evolution

The relatively low charge transfer efficiency remains the critical limiting factor for the practical application of solar-driven water splitting. In this work, a promising photocatalyst intensified by dual cocatalysts was developed via separately loading Au nanoparticles and CoP nanosheets onto the inside and outside surface of three dimensionally ordered macroporous (3DOM) g-C₃N₄ framework to significantly facilitate the ordered transfer of charges. The spatial positioning of dual cocatalysts and average wall thickness of 3DOM g-C₃N₄ framework were precisely controlled to reveal the optimal distribution position of Au and CoP as well as the most appropriate transfer distance for charges (from 3DOM g-C₃N₄ walls to the surface of cocatalysts), respectively. The results show that the spatial positioning effect of dual cocatalysts and optimization of charge transfer distance can endow the CoP/3DOM g-C₃N₄/Au photocatalyst with an excellent charge transfer efficiency, thereby contributing to high apparent quantum efficiency (AQE, 27.6% at 435 nm and 29.9% at 550 nm) and photocatalytic H₂ evolution activity of 11,820.1 μmol h⁻¹ g⁻¹, which is up to 619.9, 6.5 and 5.6 times than that of 3DOM g-C₃N₄, CoP/3DOM g-C₃N₄ and 3DOM g-C₃N₄/Au, respectively. This work would provide a new platform to design high-performance artificial photocatalysts with superior charge transfer capacity.