Branched Mesoporous TiO2 Mesocrystals by Epitaxial Assembly of Micelles for Photocatalysis

The understanding and control of the structural complexity of mesoporous semiconductors with single-crystal-like nature are both attractive and challenging. Here, we report a crystallization-driven epitaxial assembly from monomicelles to construct branched mesoporous TiO 2 mesocrystals (m-TiO 2 MCs) with coherent atomic domains. The star-shaped multipods are obtained by two-step evaporation with nanocrystal mediation, primarily consisting of arms along < 001 >, < 101 >, and < 111 > crystal directions. For each arm, ordered open mesochannels arrange in parallel along the growth direction. The m-TiO 2 MC multipods have a surface area of ∼116 m 2 /g and single-crystal-like frameworks and are good hydrogen evolution photocatalysts. Under full-spectrum irradiation, the branched m-TiO 2 MCs exhibit a hydrogen evolution rate of 8 mmol h −1 g −1 , which is more than four times higher than that of commercial TiO 2 P25. This crystallization-driven self-assembly approach may provide valuable insight into designing programmable mesoporous mesocrystals by controlling the oriented assembly of monomicelle building blocks.