Green synthesis of garlic extract stabilized Ag@CeO2 composites for photocatalytic and sonocatalytic degradation of mixed dyes and antimicrobial studies

Noble metals combined metal oxide composites have synergistic contributions to plasmonic catalysis caused by surface plasmon resonance (SPR) has emerged out as an impressive way for efficient light absorption and solar light conversion. In this work, a new approach was proposed to prepare noble metal-based CeO2 composites for the degradation of single and mixed dyes under natural sunlight and ultrasound irradiation. The garlic extract stabilized Ag@CeO2 composite was successfully prepared by Ag nanoparticles (NPs) on the surface of CeO2 via a simple method. The synthesized Ag NPs, CeO2 NPs, and Ag@CeO2 composite were investigated to determine its structural, optical, and morphological properties using powder XRD, UV-vis DRS, PL, BET, and TEM characterization techniques. The synthesized Ag@CeO2 composite having high purity and well-crystalline with an average size of similar to 5-15 nm. The Ag@CeO2 composites were utilized as photocatalyst for degradation of single dyes (methylene blue; MB and methyl orange; MO) and mixed dye (MB + MO) under sunlight and ultrasound irradiation, showing the almost inclusive degradation of MB, MO and MB + MO in 30 min due to the fast electron transfer from Ag to CeO2 and surface plasmon resonance. In addition, they were also found to possess good stability and recyclability. Moreover, the possible photocatalytic mechanism for the degradation of dyes was also proposed. The synthesized Ag@CeO2 composites were further investigated for their antimicrobial activity towards several bacteria and fungi strains. The obtained results for Ag@CeO2 have displayed the significantly improved catalytic and antibacterial properties in comparison with pure CeO2 and Ag NPs. (C) 2019 Elsevier B.V. All rights reserved.