Visible-Light-Induced Photocatalytic and Photoantibacterial Activities of Co-Doped CeO 2 .

As one of the most significant rare earth oxides, the redox ability of cerium oxide (CeO 2 ) has become the primary factor that has attracted considerable interest over the past decades. In the present study, irregular pentagonal CeO 2 (S-CeO 2 ) and different amounts of (1, 4, 8, and 12% Co) cobalt-doped CeO 2 nanoparticles (Co-CeO 2 NPs) with particle sizes between 4 and 13 nm were synthesized via the microwave-assisted synthesis method. The structural, optical, and morphological studies of S-CeO 2 and Co-CeO 2 were carried out using various techniques. The shifts in the conduction band and valence band were found to cause the reduction of the band gap energies of S-CeO 2 and Co-CeO 2 NPs. Moreover, the quenching of photoluminescence intensity with more Co doping showed the enhanced separation of charge carriers. The photocatalytic activities of S-CeO 2 and Co-CeO 2 NPs for methylene blue dye degradation, 4-nitrophenol reduction, and their photoantibacterial properties under visible-light irradiation were investigated. Findings showed that, due to the lower band gap energy (2.28 eV), more than 40% of both photocatalytic activities were observed for 12% Co-CeO 2 NPs. On the other hand, higher antibacterial impact in the presence of light shows that the Co doping has a considerable influence on the photoantibacterial response of Co-CeO 2 . Therefore, microwave-assisted synthesized CeO 2 and Co-CeO 2 NPs have shown potential in photocatalytic dye degradation, chemical reduction, and photoantibacterial activities.