Preparation and photocatalytic performance of silver nanocrystals loaded Cu2O-WO3 composite thin films for visible light-active photocatalysis

Abstract

In this work, we demonstrate a thin film-based plasmonic metal-loaded Z-scheme heterojunction composite photocatalyst Ag@Cu2O-WO3 by sputtering with enhanced photocatalytic activity upon visible-light irradiation. The amorphous WOx/Cu-WOx film has transformed into crystalline Cu2O embedded monoclinic-WO3 composite (Cu2O-WO3) during the rapid thermal annealing. The Cu2O-WO3 films showed optical bandgap ∼2.7 eV, and good optical transmittance ∼85 % @550 nm. The Ag@Cu2O-WO3 composite films show enhanced photocatalytic activity with a methylene blue degradation rate constant 3.43 × 10−3 min-1, which is ∼3.75 times higher than pure monoclinic-WO3 films. The average charge carrier lifetime of the Ag@Cu2O-WO3 is 5.24 ns, which is 1.63 times higher than that of Cu2O-WO3. The enhanced photocatalytic activity is owing to the efficient photogenerated electrons-holes separation through the combination of Z-scheme heterostructure (Cu2O-WO3) and localized surface plasmon resonance of Ag. Thus, this work provides new insight into the fabrication of very sustainable, optically transparent, reusable, and cost-effective thin film-based photocatalysts.