Control synthesis of metallic gold nanoparticles homogeneously distributed on hexagonal ZnO nanoparticles for photocatalytic degradation of methylene blue dye

Abstract

The incorporation of an appropriate amount of metallic gold nanoparticles on ZnO surface has been demonstrated to be one of the effective way in improving the photocatalytic performance of ZnO. In this novel research work, we report a facile and economical sol-gel route for synthesis ZnO doped gold nanoparticles using PVP as pore and structure directing agent. The physicochemical properties of the prepared nanoparticles were investigated by (XRD), N2-adsorption-desorption isotherm, diffuse reflectance spectra (DRS), Energy dispersive X-ray (EDX), Photoluminescence (PL), Field emission electron microscope (FESEM) and high resolution transmission electron microscope (HRTEM). Homogeneous distribution of metallic gold nanoparticles of dimension 2–3 nm on the surface of mesoporous ZnO with hexagonal bipods structure was accompanied by exceptional degradation of MB dye. A pronounced reduction of band gap energy from 3.3 to 3.08 eV upon incorporation of Au nanoparticles on ZnO surface and the reduction in the photoluminescence intensity reflects a positive influence of metallic gold nanoparticles in shifting the photocatalytic response to visible region and reducing the electron-hole recombination. The enhanced photocatalytic performance of gold doped ZnO can be attributed to the greater ability of Au to accept electron from ZnO conduction band, which in turn reducing the recombination of photoinduced electron–hole couples and increasing in the life time of reactive species. Conclusively, it can be emphasized without doubt that these Au/ZnO nanoparticles would have considerable impact on future development of hybrid photocatalysts for efficient photocatalytic degradation of various organic pollutants.