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 °C for 3 h exhibited higher catalytic activity than others. These results demonstrated that annealing conditions can play an important role in catalyst activity.