Photocatalytic Activity of Tio2 Nanostructures Formed by Sol–Gel Method in the Presence of Hydrofluoric Acid in the Transformation of Carbon Oxides

The photocatalytic activity of TiO2 nanostructures in the reduction of CO2 to CH4 and oxidation of CO to CO2 was studied. It depends significantly on the concentration of hydrofluoric acid in the sol–gel system and on the conditions of post-synthesis treatment leading to the formation of oxygen vacancies. The conditions for production of samples giving maximum efficiency for these processes were determined.