Influence of Ag/Cu photodeposition on CaTiO3 photocatalytic activity for degradation of Rhodamine B dye

The present work outlines a simple sol-gel method for the synthesis of CaTiO3 (CTO) nanoparticles followed by modification with Ag, Cu via photodeposition. Different amounts (1 to 5wt%) of Ag and Cu were loaded over CTO to form Ag/Cu-CTO nanocomposites. Several characterization techniques, such as XRD, UV-DRS, SEM, EDS, HRTEM and photoluminesence, were employed to study their structural and physicochemical properties. The photocatalytic performance of as-prepared samples was assessed by degrading Rhodamine B dye under UV irradiation. Results indicate that Ag/Cu deposition significantly enhanced the photocatalytic activity of CTO, depending upon the amount of metal loading. It found that 1 wt% Ag-CTO composite exhibited the highest (98%) photoactivity within 90 mins in contrast to 82% and 57% degradation achieved by 1 wt% Cu-CTO and bare CTO, respectively. The degradation process followed pseudo-first-order kinetics with rate constants of k=4.5×10−2 min−1 for Ag-CTO relative to k=1.8×10−2 min−1 of Cu-CTO and k=0.86×10−2 min−1 of bare. The improved photocatalytic activity was credited to the increased optical absorption and quick transfer of photoinduced electrons from CaTiO3 conduction band to Ag and Cu deposits that probably retards the charge-carriers recombination as evident by their observed photoluminance behavior.