Bi2WO6-TiO2/starch composite films with Ag nanoparticle irradiated by γ-ray used for the visible light photocatalytic degradation of ethylene

Abstract

A novel Ag-Bi2WO6-TiO2 (ABT) ternary photocatalyst was synthetized using a surface deposition and solvothermal method and its composite starch films with different amounts of ABT loading were prepared via a casting method. The morphology and microstructure of the ABT/starch composite films were characterized and their photocatalytic activity during the degradation of ethylene were evaluated. The results showed that the ABT photocatalyst exhibits excellent photocatalytic activity for the removal of ethylene under visible light with the maximum mineralization rate of 96% and CO2 production of 0.81 × 10-4. Compared with that of pure TiO2, Bi2WO6 and Bi2WO6-TiO2 composite, the reaction rate constant (k’) of ABT was improved by 188.13, 150.51, and 64.62%, respectively. When the surface loading of ABT was 2%, the photocatalytic performance of the ABT/starch film under visible-light reached its maximum with k’ increasing by 61.8% compared with the starch film without ABT loading on the surface. The improvement in the photocatalytic activity was attributed to the synergistic effect of nano-Ag, TiO2 and Bi2WO6. Ag nanoparticles are anchored on the Bi2WO6-TiO2 heterojunction, which increases the number of reactive active sites, broadens the absorption of visible light and produces more active species ·O2– and ·OH, thus enhancing the photocatalytic performance. The cooperative synergy over as-prepared ABT formed by multiple electron transfer channels composed of localized surface plasmon resonance (LSPR) enhancement, Z-sheme charge transfer and electronic sink effect results in effective charge separation and inhibits the recombination of photogenerated carriers, thus exhibiting exceptional photocatalytic activity.