Tuning the concentration of surface/bulk oxygen vacancies in CeO2 nanorods to promote highly efficient photodegradation of organic dyes

Abstract To enhance the photodegradation ability of CeO2 for organic dyes, an effective strategy is to introduce oxygen vacancies (Vo). In general, the introduced Vo are simultaneously present both on the surface and in the bulk of CeO2. The surface oxygen vacancies (Vo-s) can decrease the band gap, thus enhancing light absorption to produce more photogenerated e− for photodegradation. However, the bulk oxygen vacancies (Vo-b) will inhibit photocatalytic activity by increasing the recombination of photogenerated e− and Vo-b. Therefore, regulating the concentrations of Vo-s to Vo-b is a breakthrough for achieving the best utilization of photogenerated e− during photodegradation. We used an easy hydrothermal method to achieve tunable concentrations of Vo-s to Vo-b in CeO2 nanorods. The optimized CeO2 presents a 70.2% removal of rhodamine B after 120 min of ultraviolet − visible light irradiation, and a superior photodegradation performance of multiple organics. This tuning strategy for Vo also provides guidance for developing other advanced metal-oxide semiconductor photocatalysts for the photodegradation of organic dyes.