Synthesis of Cross-like TiO2 Thermally Derived from Ammonium Oxofluorotitanate Mesocrystals Under Different Calcination Temperatures and Their Photocatalytic Activity

Synthesis of anatase titanium dioxide (TiO2) catalysts with excellent photocatalytic activity is of great importance in photocatalytic application. In this work, a cross-like anatase TiO2 structure is obtained by thermal treatment of precursors synthesized in an electrochemical cell with mixed phases of (NH4)(2)TiOF4 and NH4TiOF3. When calcined at various temperatures, these obtained anatase TiO2 products could preserve their original morphologies and structures until 750 degrees C and kept anatase phase from rutile till 900 degrees C showing better thermal and structural stability, which was probably associated with fluoride contents on the surface of anatase TiO2 products after conversion from (NH4)(2)TiOF4 and NH4TiOF3 precursors. The photocatalytic activity of prepared TiO2 samples over methyl orange is investigated. The photocatalytic activity of mesocrystalline TiO2 cross decreases with the increase of the calcination temperature of ammonium oxofluorotitanates except for a best performance at 600 degrees C. The calcination temperature-dependent catalytic performance of the products could be ascribed to the removal of fluorine, nitrogen, or hydroxyl radicals on the surface, and the change of crystallinity and crystallite size with varying heating temperatures. The results indicated that anatase TiO2 mesocrystals calcined at 600 degrees C showed the highest photocatalytic performance more likely owing to well-defined morphology, good microstructure, and suitable crystallite size.

Automated summary

Synthesis of cross-like anatase TiO2 structures with excellent photocatalytic activity through thermal treatment of precursors synthesized in an electrochemical cell is studied. The obtained anatase TiO2 products can maintain their original morphologies and structures until 750 degrees C and show good thermal and structural stability. Anatase TiO2 mesocrystals calcined at 600 degrees C exhibit the highest photocatalytic performance.