Design of TiO2 nanocrystals with enhanced sunlight photocatalytic activity by exploring calcining conditions

As a promising inorganic semiconductor photocatalyst, TiO2 has been widespread concerned since 1972. However, its practical application is limited due to its low efficiency for utilizing solar light and rapid recombination of photo-generated charges. Here, we report a way to solve these problems by calcining TiO2 samples under different conditions. It was found that the catalytic performance of TiO2 catalysts was closely related to calcination temperature and calcination atmosphere. The XRD, Raman spectra, BET, UV-vis spectra, SEM and TG-DTA investigations of the catalysts revealed that the crystal structure of TiO2, the specific surface area, and abundant oxygen vacancies were the primary factors influencing the performance of TiO2 catalysts. Consequently, the TiO2 nanocrystal calcined in a nitrogen/hydrogen mixed atmosphere at 300 degrees C for 3 h exhibited higher catalytic activity than others. These results demonstrated that annealing conditions can play an important role in catalyst activity.