10 - A facile biogenic-mediated synthesis of Ag nanoparticles over anchored ZnO for enhanced photocatalytic degradation of organic dyes

Abstract

A facile biogenic-mediated synthesis of silver nanoparticles (NPs) anchored over zinc oxide (Ag-ZnO) was prepared by using waste pepper pod extract. The phytocompounds present in the pepper pod extract, which help to reduce the Ag ions into Ag NPs, were anchored over ZnO surface. The prepared particles were characterized using X-ray Diffractometer (XRD), UV-Vis spec, Field Emission Scanning Electron Microscope (FESEM), Energy Dispersive X-Ray Analyzer (EDX), Field Emission Transmission Electron Microscope (FETEM), and Fourier-transform infrared spectroscopy (FTIR) studies confirmed the formation of Ag-NPs anchored over ZnO. The prepared composite NPs were utilized for the photocatalytic degradation of methylene blue (MB) and congo red (CR) dyes under sunlight were explored. Compared to pristine ZnO, Ag NPs anchored over ZnO showed better photocatalytic efficiency toward MB and CR dye degradation under sunlight. Within 10 min of exposure under sunlight, ～98% degradation of MB and CR dye was observed. The enhanced degradation of the dyes due to Ag NPs anchored over ZnO surface acts as an electron trap, which leads to enhanced formation of photogenerated radicals. The reuse and recyclability of the photocatalyst were performed up to six cycles, and the result reveals that ～96% degradation of dyes was observed. This biogenic synthesized Ag-ZnO nanocomposite can be successfully utilized to treat various organic contaminants present in water with harnessing sunlight for sustainable environmental applications.