Aluminum-Doped TiO2 with Dominant {001} Facets: Microstructure and Property Evolution and Photocatalytic Activity

In order to improve the photocatalytic performance of TiO2-basedphotocatalysts, a series of Al-doped TiO2dominated with {001} facets (denoted asAl-TiO2-xFx{001}) were prepared via a facile one-step hydrothermal method. The origin of the exceptionally high activity of Al-doped TiO2catalysts under Xe lampirradiation has been investigated by XPS, solid-state NMR, and ESR spectroscopy.Two-dimensionalfluorine-detected19F-27Al heteronuclear multiple quantum correlation (19F{27Al} D-HMQC) NMR technique was applied for thefirst time toinvestigate the F-Al proximity, which confirmed the formation of the F-Ti2Alstructure in the Al-TiO2-xFx{001}samples. The quantitative27Al and19F NMRmeasurements illustrated that the enhanced activity was closely correlated with theamount 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 photo generated carriers and thus is considered as the active site responsible for the improved photocatalyticperformance. The optimal RhB photodegradation activity of Al-doped TiO2dominated with {001} facets is 1.9 and 4.9 times higher than that of TiO2dominated with {001} facets and P25, respectively.

Automated summary

In this study, Al-doped TiO2 photocatalysts with optimized {001} facet structure were prepared, showing significantly enhanced photocatalytic performance. The formation of F-Ti2Al structure was confirmed by NMR and ESR experiments, and it was identified as the active site responsible for the improved photocatalytic performance.