Abstract

In order to improve the photocatalytic performance of TiO2-based photocatalysts, a series of Al-doped TiO2 dominated with {001} facets (denoted as Al–TiO2–xFx{001}) were prepared via a facile one-step hydrothermal method. The origin of the exceptionally high activity of Al-doped TiO2 catalysts under Xe lamp irradiation has been investigated by XPS, solid-state NMR, and ESR spectroscopy. Two-dimensional fluorine-detected 19F–27Al heteronuclear multiple quantum correlation (19F{27Al} D-HMQC) NMR technique was applied for the first time to investigate the F–Al proximity, which confirmed the formation of the F–Ti2Al structure in the Al–TiO2–xFx{001} samples. The quantitative 27Al and 19F NMR measurements illustrated that the enhanced activity was closely correlated with the amount of F–Ti2Al structure. Combined with the spin-trapping ESR experimental results, it can be concluded that the F–Ti2Al structure formed in the catalyst facilitates the separation and transfer of photogenerated carriers and thus is considered as the active site responsible for the improved photocatalytic performance. The optimal RhB photodegradation activity of Al-doped TiO2 dominated with {001} facets is 1.9 and 4.9 times higher than that of TiO2 dominated with {001} facets and P25, respectively.

链接：https://pubs.acs.org/doi/10.1021/acs.jpcc.2c00537