| Abstract
| - Two series of binary oxide catalysts (CuGa/SA and CuSn/SA) containing CuO coupled with Ga2O3 orSnO2 were prepared by dispersing the metal phases onto a high surface area acidic silica−alumina (SA)support by an adsorption method. Similar total amounts of metals (about 1.6 atomMet·nm-2) were depositedonto the support, in different proportions, to obtain samples with weight percent of copper varying from3.3 to 6.5% The SA support was first covered by the copper precursor, Cu(C2H3O2)2, and then gallium(Ga(NO3)3·H2O) or tin (SnCl4·5H2O) precursors were deposited on the dried Cu-containing sample. Thecalcined materials were characterized by surface techniques (N2 adsorption and XPS), to detect the surfacemorphology and chemical state of metal species, and by FT-IR and adsorption calorimetry after COadsorption. Nanosized metal phases were observed in every case. Besides Cu(II), the surfaces containedCu(I) as well as Cu(δ+) ions (with 1 < δ < 2) stabilized by the interaction with the acid centers of thesupport. Gallium oxide preferentially covered the copper oxide phase, while tin dioxide mainly depositedon the bare surface of the support. The reducibility properties of the different supported metal oxideswere investigated by TPR from both the qualitative and quantitative points of view. The catalyticperformances of the simple and binary surfaces were comparatively studied in different reactions(decomposition and reduction of N2O and NO, and CH4 combustion) considered as test reactions toinvestigate the reducing or oxidizing properties of the materials. The observed differences in catalyticactivity among the catalysts are discussed in relation with the surface composition and properties.
- Two series of dispersed binary oxide catalysts containing CuO coupled with Ga2O3 or SnO2 were prepared and characterized by various techniques. Intimate contact between CuO and Ga2O3 and scarce interactions between CuO and SnO2 were observed. The catalytic properties were tested in decomposition and reduction of NOx and oxidation reactions.
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