Hydrothermal synthesis and characterization of novel PbWO4 microspheres with hierarchical nanostructures and enhanced photocatalytic performance in dye degradation

Abstract Novel PbWO 4 crystals with different morphologies, 14-faceted polyhedrons, hierarchical microspheres and nanoparticles, were fabricated by adjusting pH value under hydrothermal conditions. The as-prepared PbWO 4 samples were characterized by nitrogen-physical adsorption, powder X-ray diffraction, scanning electron microscopy, transmission electron microscopy, UV–vis diffuse reflectance spectra, photoluminescence emission spectroscopy, and Fourier transform infrared spectroscopy. The photocatalytic performance of the PbWO 4 crystals with different nanostructures in degradation of the acid orange II dye under UV light (365 nm) was investigated. The plausible growth mechanisms for PbWO 4 crystals with different morphologies were proposed. Photocatalytic tests showed that the performance of PbWO 4 crystals strongly depended on their morphologies. PbWO 4 microspheres with hierarchical nanostructures prepared under pH 7.0 at 140 °C exhibited the highest activity and stability in recycling reaction. The degradation kinetics of dye over PbWO 4 crystals was found to conform to the pseudo-first order model. The enhanced photocatalytic performance was attributed to the unique hierarchical nanostructures with high surface area and improved surface properties. Moreover, the high crystallinity of PbWO 4 microspheres exhibited an enhanced catalytic activity owing to lower recombination rate of photo-generated electron/hole pairs. These novel hierarchical PbWO 4 microspheres hold promise in applications of environmental purification.