Processing-structure-property relationships of Bi2WO6 nanostructures as visible-light-driven photocatalyst

QDS modified Bi2WO6 (BWO) nanostructures were processed by calcination at different temperatures. A strong correlation was found among the processing, structure and properties of the samples. With increasing calcination temperature from 200 °C to 500 °C, the crystallinity increased and the BWO QDS gradually disappeared from the nanostructures. Both surface area and band gap of the samples decreased. The light absorption of the samples became lower for the long-wavelength range, accompanied by a red shift of the absorption edge. The photocatalytic activity of the samples decreased after calcination at higher temperature. The competitive relations between crystallinity and surface area in affecting photocatalytic activity were discussed. The role of BWO QDS that played in enhancement of photocatalytic activity was also revealed by studying structure and property evolution of the calcined samples.