Microwave-assisted growth of WO3·0.33H2O micro/nanostructures with enhanced visible light photocatalytic properties

Abstract

Various micro/nanostructured WO3·0.33H2O crystallites were successfully controlled by employing microwave heating under different conditions. By using X-ray diffraction, scanning electron microscopy, transmission electron microscopy and high resolution transmission electron microscopy, the phase and morphology of the products were identified. Comparing the as-prepared crystallites under conventional and microwave heating processes found that microwave heating may play a crucial role to initiate the oriented growth of orthorhombic WO3·0.33H2O micro/nanostructures. Moreover, these oriented structures exhibit clearly improved photocatalytic activity over the structures prepared under the conventional heating process. By applying the multi-site complexation model, the improved photocatalytic properties were found to relate to the exposure of high surface acidity orthorhombic WO3·0.33H2O crystallites, which originate from the oriented growth of microstructures prepared under the microwave heating process.