In this study, Au/ZnO nanocomposites of different gold contents (0.8, 2.5, and 9%) and specific surface areas (from 41 to 51 m2/g) were synthesized via a coprecipitation method. The pure ZnO was obtained at the same experimental conditions. The samples were characterized by XRD, SEM, TEM, HRTEM, and XPS. The influence of gold nanoparticles (Au-NPs) loading on the catalytic activity of Au/ZnO nanocomposite was studied in the model reaction of CO oxidation. Spherical shape and homogeneous distribution of Au-NPs were observed in all samples prepared. The average size of Au-NPs in the obtained catalysts are almost the same (about 4 nm) allowing the studied effect to be manifested. The decrease of intrinsic catalytic activity of the coprecipitated Au/ZnO nanocomposites follows the sequence 2.5, 9, and 0.8% Au, as corresponding to the decrease of relative surface content of Au-NPs. It could be suggested that the catalytic activity is noticeably influenced by the distribution of Au-NPs between the bulk and surface of catalysts.
Select Area Electron Diffraction Gold Content Coprecipitation Method Crystal Lattice Parameter Good Catalytic Performance
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This study has been financially supported by the Scientific Research Fund of Sofia University, Bulgaria (Project 014/2010). The authors are thankful to Dr. Peter Tzvetkov (Bulgarian Academy of Sciences) for interpretation of the XRD data.