Designing charge transfer route at the interface between WP nanoparticle and g-C₃N₄ for highly enhanced photocatalytic CO₂ reduction reaction

Developing metallic co-catalysts is an effective way to enhance the photocatalytic activity of semiconductor by forming the Schottky junction, but it remains challenging to unveil the design principle. Herein, a novel nanocomposite is prepared by coupling ultra-small WP nanoparticles embedded on N-doped carbon (WP–NC) with 2D graphitic C₃N₄ (g-C₃N₄). The WP–NC and g-C₃N₄ form an intimate interface via PN– chemical bonds at atomic level, which facilitates the flow of photoexcited electrons from g-C₃N₄ to WP–NC. Moreover, the Schottky junction formed at the interface can prevent the charge-carrier recombination in the WP–NC/g-C₃N₄ composite and thus significantly enhance the photocatalytic CO production rate from 29 (bare g-C₃N₄) to 376 μmol g⁻¹ h⁻¹. As the first example of WP applied on the photocatalytic CO₂ reduction, this work demonstrates the potential of metallic WP as a co-catalyst in photocatalysis and provides a useful guide on the phosphide-based material designing.