Nanocavity-assisted single-crystalline Ti³⁺ self-doped blue TiO₂(B) as efficient cocatalyst for high selective CO₂ photoreduction of g-C₃N₄

Two-dimensional (2D) graphitic carbon nitride (g-C₃N₄) has invoked significant interest for photocatalytic applications for its excellent features such as high surface area, visible light absorption, and easy transportation of photogenerated charge carriers, but the most reported g-C₃N₄ show relatively low photoactivity due to inferior conductivity and rapid recombination of carriers. These can be overcome by inducing porosity in g-C₃N₄, followed by exfoliation and combining with other materials. Herein, we synthesize nanocavity-assisted oxygen-deficient Ti³⁺ self-doped blue TiO₂(B) nanorods (BT) and integrate them on exfoliated porous g-C₃N₄ (PCN). The synthesized materials are tested for photocatalytic conversion of CO₂ into solar fuels (H₂, CO, and CH₄). The fabricated BT/PCN heterostructures exhibit higher photocatalytic CO₂ conversion activity and 92% CO-evolving selectivity than BT and PCN. The enhancement in activity of BT/PCN can be attributed to the efficient separation and transportation of charge carriers, facilitated by the unique properties of BT, PCN, and their synergistic interactions. We believe that these results can contribute to the improvement of cost-effectiveness, feasibility, and overall performance for real photocatalytic systems.