In Situ Formation of Micropore-Rich Titanium Dioxide from Metal-Organic Framework Templates

Phase and porosity control in titanium dioxide (TiO₂) is essential for the optimization of its photocatalytic activity. However, concurrent control over these two parameters remains challenging. Here, a novel metal-organic framework templating strategy is demonstrated for the preparation of highly microporous anatase TiO₂. In situ encapsulation of Ti precursor in ZIF-8 cavities, followed by hydrolysis and etching, produces anatase TiO₂ with a high Brunauer-Emmett-Teller surface area of 335 m²·g^-1 and a micropore surface area ratio of 48%. Photocatalytic hydrogen generation catalyzed by the porous TiO₂ can reach a rate of 2459 μmol·g^-1·h^-1. The measured photocatalytic activity is found to be positively correlated to the surface area, highlighting the importance of porosity control in heterogeneous photocatalysts.