The dual effects of RGO films in TiO2/CdSe heterojunction: Enhancing photocatalytic activity and improving photocorrosion resistance

Through TiO2/CdSe heterojunction has achieved outstanding performance in the field of photocatalysis, the serious photocorrosion of CdSe limits the service life of TiO2/CdSe heterojunction. Herein, we report a method to enhance both the photocatalytic activity and the photocorrosion resistance of TiO2/CdSe by spin coating reduced graphene oxide (RGO) films on TiO2/CdSe heterojunction films. RGO could work as photo-induced electron acceptor to improve the separation efficiency of photo-induced electron and hole pairs, thus enhancing the photocatalytic activity of TiO2/CdSe heterojunction. On the other hand, RGO could prevent the direct contact between CdSe nanoparticles and oxygen dissolved in solution, which would avoid the reaction between CdSe and oxygen to form soluble Cd2+ and SeO42- for the dissolution of CdSe nanoparticles during the photocatalytic reaction process. Thus, RGO film promotes the overall photocatalytic performance of TiO2/CdSe heterojunction and restrains secondary Cd2+ pollution occurred in its photocatalytic reaction. The dual merits of RGO film with enhanced photocatalytic activity and improved photocorrosion resistance are helpful not only for developing high performance TiO2/CdSe photocatalysts but also for other photocatalyst systems. This work sheds a light on loading RGO on a support aiming to significantly improve its photocatalytic performance and photocorrosion resistance in organic pollutants degradation.