A 3D Hierarchical Ti₃C₂T_x/TiO₂ Heterojunction for Enhanced Photocatalytic CO₂ Reduction

Abstract The construction of three‐dimensional (3D) hierarchical photocatalysts from two‐dimensional (2D) nanosheets has attracted lots of interest due to its unique structural properties. Herein we design a 3D hierarchical structure of Ti₃C₂T_x based on its 2D prototype as a precursor. TiO₂ is in‐situ formed on the surface of Ti₃C₂T_x nanosheet by calcination, thereby obtaining a 3D hierarchical TiO₂/Ti₃C₂T_x heterojunction. The rational design induces the intimate coupling of TiO₂ and Ti₃C₂T_x, and macro‐mesopores in the hierarchical structure. The optimized sample exhibits a relatively high photocatalytic CH₄ evolution activity of 4.41 μmol ⋅ g⁻¹ ⋅ h⁻¹, which is almost twice that of P25 (2.32 μmol ⋅ g⁻¹ ⋅ h⁻¹). The enhanced photocatalytic performance arises from the more efficient electron‐hole separation and better light harvesting of the 3D hierarchical structure. Moreover, the excellent CO₂ adsorption ability of Ti₃C₂T_x also ensures effective contact between CO₂ molecules and photoinduced electrons from TiO₂. This work demonstrates a facile strategy for the preparation of precursor‐induced functional materials toward various applications.