Energy efficient sunshine active Ag decorated WO3/HNT nanocomposite for accelerated detoxification of hazardous dye-based emerging pollutant

Abstract

Herein, we report that the tungsten trioxide (WO3) nanosheets and 2%Ag/15%WO3/HNT (Ag/WO3/HNT) composite photocatalysts were synthesized by the hydrothermal process and solvent evaporation methods. Various characterization techniques such as XRD, FT-IR, FE-SEM, EDS, HR-TEM, and UV-DRS were used to investigate the bulk and surface properties of bare and composite photocatalysts. The photocatalytic performance of halloysite nanotube (HNT), WO3/HNT, and Ag/WO3/HNT composite photocatalysts were evaluated by methylene blue (MB) dye degradation efficiency under solar light irradiation for 90 min. Among the various catalysts, Ag/WO3/HNT photocatalyst showed significant photocatalytic performance (96% degradation for MB dye). The existence of Ag indicates that surface plasmon resonance (SPR) impacts the developed composite and acts as an electron mediator. The scavenger experiment showed that the superoxide radical anions play a significant role in MB degradation under solar light with the most active Ag/WO3/HNT photocatalyst. The degradation of the MB dye has been monitored by Total Organic Carbon (TOC) measurements. The degradation intermediates of MB were analyzed by GC-MS, and a suitable degradation pathway was proposed. The most active Ag/WO3/HNT photocatalyst was also found to be the most stable and recyclable. The trapping experiment with Ag/WO3/HNT composite catalyst has led to the development of a dye degradation mechanism.