Novel　PbWO4　crystals　with　different　morphologies,　14-faceted　polyhedrons,　hierarchical　microspheres　and　nanoparticles,　were　fabricated　by　adjusting　pH　value　under　hydrothermal　conditions.　The　as-prepared　PbWO4　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　PbWO4　crystals　with　different　nanostructures　in　degradation　of　the　acid　orange　II　dye　under　UV　light　(365　nm)　was　investigated.　The　plausible　growth　mechanisms　for　PbWO4　crystals　with　different　morphologies　were　proposed.　Photocatalytic　tests　showed　that　the　performance　of　PbWO4　crystals　strongly　depended　on　their　morphologies.　PbWO4　microspheres　with　hierarchical　nanostructures　prepared　under　pH　7.0　at　140　degrees　C　exhibited　the　highest　activity　and　stability　in　recycling　reaction.　The　degradation　kinetics　of　dye　over　PbWO4　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　PbWO4　microspheres　exhibited　an　enhanced　catalytic　activity　owing　to　lower　recombination　rate　of　photo-generated　electron/hole　pairs.　These　novel　hierarchical　PbWO4　microspheres　hold　promise　in　applications　of　environmental　purification.　(C)　2013　Elsevier　B.V.　All　rights　reserved.