Biomediated synthesis of Nano Metal Oxides and Nanocomposite Metal Oxidesfor Photocatalytic and Antimicrobial Applications

Abstract

Now days, water contamination caused by various sources have drawn a series attention. In addition to this, antimicrobial caused diseases have become series issue worldwide, especially for developing countries. The focus of the present study was biogenic synthesis of Co3O4 NPs, TiO2/rGO, and ZnO/CuO NCs within various volume ratios in the presence of peel extract of ST, CS, and MA, respectively. It was observed that Co3O4 NPs were stable above 450 , and were spherical in shape, and had the average crystalline size of, 13.5-19.45 nm, and band gap energy of 3.25- 3.37 eV for the 1:2, 1:1 and 2:1volume ratios, respectively. SEM-EDS, TEM, HRTEM and SAED confirm that the NPs were spherical in shape and crystalline. Thermal analysis of green synthesized TiO2 based NPs confirmed that the pristine NPs were found to be stable above 500℃ having average crystalline size in the range of 7-27 nm and 13-22 nm for the CS and MA, respectively. The average crystalline size of CS and MA peel extract templated synthesized TiO2/rGO NCs were found to be in the range of 7-15and 11-12nm, respectively. The band gap energy was calculated to be in the range of 3.17-3.29 eV and 3.10-3.38 eV for the CS and MA mediated synthesized TiO2 NPs, respectively. While Eg of CS and MA peel extract templated formed TiO2/rGO NCs were found in the range of 2.85-3.11 eV and 3.07-3.11 eV, respectively. SEM analysis proved that TiO2 NPs and TiO2/rGO NCs were spherical in shape. TEM, HRTEM, and SAED confirmed that the NPs and NCs nanocatalysts were spherical and crystalline. The average crystalline size of ZnO NPs were found to be within 24.9-28.2 nm for the 1:1, 1:2, and 1:3, respectively and 17.0 nm for CuO NPs. The average crystalline sizes of ZnO/CuO NCs were found within the range of 22.6-22.9 nm for 10%, 15%, 20% and 25%, respectively. SEM and TEM analysis confirmed that ZnO NPs, CuO NPs, and ZnO/CuO NCs were spherical shape. of ZnO NPs were 3.24-.24 eV for the 1:1, 1:2, and 1:3, respectively. of CuO NPs were estimated to be 1.7 eV and that of ZnO/CuO NCs decreased from 3.24 to 3.05eV. 94.28%, 94.25%, and 90% of MB degradation were achieved in the presence of TiO2/rGO-1.5c, TiO2/rGO-1.5m, and ZnO/CuO (20%) catalyst, respectively. ZnO/CuO (20%) NCs and Co3O4 (1:2) NPs showed 22 and 27 mm ZOI, respectively. ZnO/CuO (20%) and Co3O4 (1:2 and 1:1) NPs showed 0.40 and 0.00 MGI against Alternaria Solani, respectively.