effect of wo3 nanoparticles on congo red and rhodamine b photo degradation

tungsten trioxide nanoparticles with two different sizes (average particle sizes about 50 and 80 nm) were prepared by the spray pyrolysis method. photo degradation of congo red (azo dye) showed that photo catalytic property of the as-prepared wo3 nanoparticles with average size about 80 nm is higher than the sample with average size about 50 nm. photo degradation of rhodamine b (cationic triarylmethane dye) showed that photo catalytic property of the as-prepared wo3 nanoparticles with average size about 50 nm is higher than the sample with average size about 80 nm. the samples were characterized with x-ray diffraction (xrd), scanning electron microscopy (sem), edx analysis and uv-visible spectrum. different interactions between dyes and the photo catalyst surface, probably causes the inverse behavior of wo3 nanoparticles with two different sizes in congo red and rhodamine b photo degradation reactions.