Surfactants-assisted synthesis of ZnWO4 nanostructures: A view on photocatalysis, photoluminescence and electron density distribution analysis

In this study, we synthesized zinc tungstate (ZnWO4) nanoparticles with the aid of three various surfactants such as hexamethylenetetramine (HMTA), polyvinylpyrrolidone (PVP) and sodium dodecyl sulfate (SDS) through simple co-precipitation route. The as-prepared ZnWO4 nanostructures were successfully confirmed by numerous analytical and spectroscopic techniques. For the first time, the as-prepared ZnWO4:HMTA, ZnWO4:PVP and ZnWO4:SDS materials were utilized as photocatalyst for the degradation of ciprofloxacin (CIP) drug and photoluminescent material for solid state lighting devices. More interestingly, the ZnWO4:PVP material exhibited excellent photocatalytic behavior towards CIP degradation with efficiency of above 97% under UV-light illumination. The enhanced photocatalytic activity was attributed to the well-defined hexagonal plate-like structure, superior optical band gap, lower PL intensity and reduced particle size when compared to other ZnWO4:HMTA and ZnWO4:SDS materials. On the other hand, ZnWO4:SDS displayed an intense blue-green emission in the wavelength range at similar to 470 nm due to intrinsic WO66- complex with higher luminescence intensity when compared to others. Furthermore, the electron density distributions studies were carried in order to extract the variation of bond length between the atoms and density of electrons at the middle of the bonds in a single unit cell.