Fabrication and characterization of C–doped TiO 2 nanoparticles for the photodegradation of organic dyes

A low-cost sol-gel method is used to synthesize C-doped TiO2 (C–TiO2) nanoparticles. Nanoparticles of undoped TiO2 and varying C weight percentages (4%, 6%, and 8%) of C–TiO2 are generated. XRD, FTIR, FESEM-EDS, UV–Vis DRS, PL, BET, and XPS are used to analyze the characteristics of all the nanoparticles. The EDS data indicate that the TiO2 lattice has been successfully doped with carbon. The band-gap energy of 6% C–TiO2 is shifted to 2.94 eV, as confirmed by UV–Vis DRS, resulting in improved visible-light absorption and, hence, increased photocatalytic activity by lowering the electron-hole recombination rate. Under natural sunlight irradiation, 6% C–TiO2 achieves a 91% removal efficiency of Rhodamine B (RhB) dye in 90 min and 84% removal efficiency of Congo Red (CR) dye in 30 min. A probable photodegradation pathway was estimated using the scavenger test, and the •O2− and •OH radicals are recognized as potentially active species for RhB degradation.