A Novel Approach for P25‐Carbon Dot Composite and the Reactive Oxygen Species Involved in the Visible Light Photocatalytic Mineralization of Rhodamine B

Abstract

AbstractA novel approach has been adapted for making titanium dioxide (P25)‐carbon dot composite (P25/C‐dot) and it exhibits visible light (VL) photocatalytic mineralization property towards rhodamine B (RhB). Carbonization of β‐cyclodextrin (CD) in a self‐assembled P25/β‐cyclodextrin (P25/CD) composite prepared by UV‐irradiation, using P2O5‐water yields P25/C‐dot with chemical linkage between P25 and C‐dot. Photodegradation (PD) of RhB by P25/CD and P25/C‐dot were better (71%) than that of the commercial P25 (49%). Though the PD activity of both the composites was similar, the PD of RhB by P25/C‐dot follows the mineralization pathway while that in the presence of P25/CD undergoes via decolouration. Further scavenging studies reveal that hydroxyl radicals (•OH) are the dominant reactive oxygen species (ROS) in the PD of RhB by P25/C‐dot while it is superoxide anion radical (O2•−) and singlet oxygen (1O2) for P25/CD, suggesting that •OH can promote mineralization of the RhB. Our study suggests that C‐dot has a role in the formation of •OH during PD reaction, catalytically or not.