Selective CO oxidation with nano gold particles-based catalysts over Al2O3 and ZrO2

We present the preparation, characterization and catalytic evaluation of gold-based catalysts over Al2O3, ZrO2 and 10% ZrO2/Al2O3 in selective CO oxidation. Oxidation and reduction pretreatments were evaluated using in situ X-ray diffraction, and the size of gold particles was determined. All catalysts contained gold particles in the range of 2–5 nm, with as-prepared samples containing a mixture of gold species (Au3+ and Au0). The catalytic tests showed complete CO oxidation at temperatures lower than 100 °C, with Au/ZrO2 sample presenting the best performance. Both the support and pretreatment conditions were found to cause changes to gold species. In situ X-ray diffraction patterns indicated the presence of different gold phases and of nanometer-scale crystallites of gold, which was confirmed by transmission electron microscopy results. It was also found that cationic gold improved the activity of Au/ZrO2. Concerning stability, time on stream tests showed that all samples were stable to coke deposition and sintering.

Gold catalysts nano-dispersed on oxide supports Al2O3, ZrO2 and 10% ZrO2/Al2O3 were evaluated in selective CO oxidation. In situ XRD experiments were performed to identify the active phase and the average size during reaction. No significant changes were observed in the average size after 60 h on stream, and that the active phase depends strongly on the support.Figure optionsDownload as PowerPoint slide