WGS and CO-PrOx reactions using gold promoted copper-ceria catalysts: “Bulk CuO CeO2 vs. CuO CeO2/Al2O3 with low mixed oxide content”

Abstract

A copper-ceria bulk catalyst has been compared to a series of catalysts designed according to the as called "supported approach", corresponding to the dispersion of low content mixed copper-ceria oxide on alumina matrix. The principal characteristics of both types of catalysts are contemplated and the differences in their electronic and redox properties discussed in details. As a plus, the gold metal promotion of the catalysts is also envisaged. The advantages of the systems in the CO clean up reactions, WGS and CO-PrOx are commented. While the WGS activity appears to be ruled especially by the Cu/Ce surface to volume ratio, the CO-PrOx reaction is governed by the CuO loading. Gold addition provides benefits only at the low temperature WGS regime. Very importantly, the supported systems are always superior to the bulk configuration in terms of specific activity, a key factor from the catalyst's design perspective.

Synthesis and characterization of Rh/MnO 2 -CeO 2 /Al 2 O 3 catalysts for CO-PrOx reaction

“…This behavior suggests that the R-WGS occurrence is seems to be more promoted by the manganese presence at higher temperatures. In fact the decrease in CO 2 selectivity is more pronounced in these solids ( selectivity has been also related to that the rate of hydrogen oxidation exceeds that of carbon monoxide oxidation at higher temperatures [12]. In this case the hydrogen oxidation is seems to be more promoted by the Ce presence than Mn since for RhCe 50 Al the O 2 conversion is always 100%.…”

“…The reported promising catalysts for CO-PrOx reaction could be grouped into three classes: (i) Supported noble metal catalysts, such as Pt, Pd, Ir, Ru and Rh [5][6][7][8][9], (ii) Nano-gold catalysts [10] and (iii) Metal oxides catalysts, mainly bulk CuO-CeO 2 [11][12][13][14][15] or supported CuO-CeO 2 catalysts [12,16], and Co-Ni oxides [17]. Zhou et al [17] investigated the catalytic properties of Ni, Co and Co-Ni supported on activated carbon for CO-PrOx reaction.…”

“…This is normally carried out in fuel processors where WGS and CO-PrOx reactions are coupled as integrated stages. Herein, CuO-CeO 2 systems have demonstrated outstanding activity for both mentioned reactions and therefore they are intimately linked to the development of the last generation of hydrogen alimented fuel cells [12,15]. Barbato et al [11] reported very active catalyst for oxidation reactions based on CuO-CeO 2 catalysts prepared by solution combustion synthesis with respect to the typically ones synthesized by impregnation method [12][13][14][15].…”

“…Herein, CuO-CeO 2 systems have demonstrated outstanding activity for both mentioned reactions and therefore they are intimately linked to the development of the last generation of hydrogen alimented fuel cells [12,15]. Barbato et al [11] reported very active catalyst for oxidation reactions based on CuO-CeO 2 catalysts prepared by solution combustion synthesis with respect to the typically ones synthesized by impregnation method [12][13][14][15]. Reina et al [12,15] reported that the catalytic system CuO-CeO 2 is very active and selective for CO oxidation and WGS reaction in the presence of a large amount of H 2 and that the selectivity increases when gold is also incorporated.…”

“…Barbato et al [11] reported very active catalyst for oxidation reactions based on CuO-CeO 2 catalysts prepared by solution combustion synthesis with respect to the typically ones synthesized by impregnation method [12][13][14][15]. Reina et al [12,15] reported that the catalytic system CuO-CeO 2 is very active and selective for CO oxidation and WGS reaction in the presence of a large amount of H 2 and that the selectivity increases when gold is also incorporated. Despite the benefits of the inclusion of gold in the formulation of CuO-CeO 2 catalysts, the addition of a noble metal (even in low quantities) would increase the cost of the final catalyst.…”