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

2008; Elsevier BV; Volume: 347; Issue: 1 Linguagem: Inglês

10.1016/j.apcata.2008.05.030

1873-3875

Nielson F.P. Ribeiro, Fabiana Magalhães Teixeira Mendes, Carlos A. Perez, Mariana M.V.M. Souza, Martín Schmal,

Catalysts for Methane Reforming

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.