Fabrication of g-C₃N₄/Au/C-TiO₂ Hollow Structures as Visible-Light-Driven Z-Scheme Photocatalysts with Enhanced Photocatalytic H₂ Evolution

The Z-scheme photocatalytic system for water splitting based on semiconductors has exhibited great potential for H₂ fuel production from renewable resources. In this work, we constructed g-C₃N₄/Au/C-TiO₂ hollow spheres as an all-solid-state Z-scheme photocatalytic system with Au nanoparticles as the electron mediator. The as-synthesized g-C₃N₄/Au/C-TiO₂ photocatalyst showed a remarkably enhanced photocatalytic H₂ evolution rate under visible-light irradiation (λ>420 nm), which was 86 and 42 times higher than those of pure C-TiO₂ and g-C₃N₄, respectively. The enhancement of photocatalytic performance can be mainly attributed to the intentionally designed Z-scheme system, which not only promoted the efficient transfer and separation of photogenerated electron–hole pairs, but also retained the strong redox ability of the charge carriers. In addition, the Z-scheme system also achieved high visible-light absorption and utilization owing to the surface plasmon resonance (SPR) effect of Au nanoparticles and hollow structures of C-TiO₂. All the factors synergistically promote the photocatalytic activity of the g-C₃N₄/Au/C-TiO₂ hollow nanospheres, providing a promising method for the rational design of highly efficient visible-light-driven photocatalysts.