A 3D Hierarchical Ti 3 C 2 T x /TiO 2 Heterojunction for Enhanced Photocatalytic CO 2 Reduction

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 Ti 3 C 2 T x based on its 2D prototype as a precursor. TiO 2 is in‐situ formed on the surface of Ti 3 C 2 T x nanosheet by calcination, thereby obtaining a 3D hierarchical TiO 2 /Ti 3 C 2 T x heterojunction. The rational design induces the intimate coupling of TiO 2 and Ti 3 C 2 T x , and macro‐mesopores in the hierarchical structure. The optimized sample exhibits a relatively high photocatalytic CH 4 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 CO 2 adsorption ability of Ti 3 C 2 T x also ensures effective contact between CO 2 molecules and photoinduced electrons from TiO 2 . This work demonstrates a facile strategy for the preparation of precursor‐induced functional materials toward various applications.