Synthesis of Hierarchical TiO₂–C₃N₄ Hybrid Microspheres with Enhanced Photocatalytic and Photovoltaic Activities by Maximizing the Synergistic Effect

To maximize the synergistic effect between the components in a TiO₂–C₃N₄ hybrid, strongly heterostructured three-dimensional (3D) porous TiO₂–C₃N₄ microspheres with a hierarchical nano/microstructure are developed by a solvothermal method and used as photocatalysts for organic waste degradation and as photoanodes for dye-sensitized solar cells (DSSCs), showing superior photoactivity. The rich heterojunctions and strong interfacial connections between TiO₂ and C₃N₄ greatly improve the separation efficiency of the photogenerated electron–hole pairs. This hybrid exhibits superior photocatalytic activity compared to TiO₂–C₃N₄ composites prepared by traditional physical mixing and reported post-synthesis methods. A DSSC prepared with this hybrid as the photoanode displays superior or comparable photoelectric efficiency to those of the best reported photoanodes. A possible mechanism for the improved photoactivity of this hybrid is proposed. This strongly heterostructured TiO₂–C₃N₄ hierarchical microspherical material is expected to provide a good foundation for the design and synthesis of advanced materials for photocatalytic and photovoltaic applications.