Mesoporous anatase TiO₂ mesocrystal for high-performance photocatalysis and lithium-ion batteries

Mesocrystals, with their unique structures composed of aligned nanocrystals, hold promise for energy conversion and storage applications. This study presents a novel approach to synthesizing platelike mesoporous anatase TiO₂ mesocrystals from non-porous H_1.07Ti_1.73O₄·<i>n</i>H₂O (HTO) precursors. The synthesis involves solvothermal, acid, and heat treatments, starting with the formation of a BaTiO₃/HTO (BT/HTO) nanocomposite <i>via</i> topochemical conversion. Subsequent selective acid leaching and controlled heat treatment at 700-900 °C produced mesoporous anatase TiO₂ mesocrystals with a high specific surface area and mesoporosity. These mesocrystals exhibited outstanding photocatalytic activity, achieving a surface-specific degradation efficiency of methylene blue surpassing that of commercial P25. As an anode material for lithium-ion batteries, the mesocrystals delivered an exceptional initial discharge capacity of 667.5 mA h g^-1 and maintained a reversible capacity of 243.1 mA h g^-1 after 100 cycles at 100 mA g^-1. The enhanced performance is attributed to their optimized mesoporosity, crystallinity, and nanostructural alignment. This study advances the understanding of mesocrystal synthesis and underscores the potential of mesoporous anatase TiO₂ mesocrystals in sustainable energy and environmental applications.