Effective role of trifluoroacetic acid (TFA) to enhance the photocatalytic activity of F-doped TiO₂ prepared by modified sol–gel method

Graphical abstract: - Highlights: • Surface-fluorinated TiO₂ with superior properties. • Generation of free surface hydroxyl radicals. • Excellent photo-generated electron and holes separation. • Mixed morphologies of truncated and compressed bipyramids. • Superior photo-kinetics performance. - Abstract: Highly photoactive mesoporous F-doped TiO₂ with improved physico-chemical characteristics is achieved using modified sol–gel method. The usage of trifluoroacetic as fluorine precursor significantly modifies the morphology, size, pore shape, crystal phase, crystal structure, surface chemical state and to a lesser extent, {1 0 1} and {0 0 1} facets. The accessibility of fluoride ions on Ti−O−Ti polymer chains during crystal growth during the sol–gel process remarkably influences the properties of catalyst. To the best of our knowledge, preparation of F-doped TiO₂ using modified sol–gel and trifluoroacetic acid are limited, and still not enough. Thus this work provides additional insight by using an approach which is less hazardous, less costly and practical for large scale agile development in the photocatalysis industry.