Catalytic oxidation of volatile organic compounds on manganese and copper oxides supported on titania

Abstract

in Wiley InterScience (www.interscience.wiley.com).A series of mixed oxides supported on TiO 2 (Mn 12y Cu y O x /TiO 2 ) synthesized by incipient wetness impregnation method have been characterized and tested for toluene oxidation volatile organic compounds (model). For all catalysts, the total conversion (100%) of toluene into CO 2 was obtained at temperatures higher than 2408C with no catalyst deactivation. At lower temperatures, a gradual deactivation was observed. The most efficient catalyst was Mn 0.5 Cu 0.5 O x /TiO 2 (noted MnCuO x /T). Several characterization techniques, XRD, TPR, BET, and TG/DT analysis, were used to explain the catalytic performances. The results allowed attributing the higher activity of MnCuO x /T to the formation of Mn 1.6 Cu 1.4 O 4 spinel phase. It has been also demonstrated that the mobility of the catalyst network oxygen is a determining parameter of the catalytic activity. The decrease of activity at a low temperature is related to the adsorption of high molecular weight carbonaceous compounds. However, the catalytic activity is easily regenerated by heating in air flow at 3008C.

Catalytic Combustion of Toluene over a Copper‐Manganese‐Silver Mixed‐Oxide Catalyst Supported on a Washcoated Ceramic Monolith

“…However, different Ag/Cu/Mn molar ratios exist in the active phases of these catalysts. It can be seen that for Cu-Mn mixed oxides or supported Cu-Mn mixed oxides, the Cu/Mn ratio = 1 usually led to the optimal catalytic activity for the combustion of VOCs [7,9], and therefore, the atomic ratio of Cu to Mn was fixed at 1/1 for the overall study. The curves of toluene conversion versus the reaction temperature for the six samples are shown on Fig.…”

“…Catalysts based on transition metal (Ni, Cu, Co, Cr, Mn, and Fe) oxides have been extensively studied and the combustion activity shown by these oxides is generally lower than that of noble metal catalysts [2][3][4]6]. Among the metal oxide catalysts, manganese and copper oxides have been considered as the most active and promising catalysts for the combustion of VOCs [4,6,7]. Therefore, much effort has been undertaken to improve the catalytic performance of the two oxides as well as their mixed oxides [7][8][9][10][11][12], e.g., ceria promoted copper oxide was found to be more active than single copper oxide or Cu-Mn mixed oxides [8].…”

“…Among the metal oxide catalysts, manganese and copper oxides have been considered as the most active and promising catalysts for the combustion of VOCs [4,6,7]. Therefore, much effort has been undertaken to improve the catalytic performance of the two oxides as well as their mixed oxides [7][8][9][10][11][12], e.g., ceria promoted copper oxide was found to be more active than single copper oxide or Cu-Mn mixed oxides [8]. Titania supported Mn-Cu mixed oxide with a Mn/Cu atomic ratio of 1/1 showed significantly greater activity than single manganese or copper oxide, or mixed oxides with other compositions [7].…”

“…Therefore, much effort has been undertaken to improve the catalytic performance of the two oxides as well as their mixed oxides [7][8][9][10][11][12], e.g., ceria promoted copper oxide was found to be more active than single copper oxide or Cu-Mn mixed oxides [8]. Titania supported Mn-Cu mixed oxide with a Mn/Cu atomic ratio of 1/1 showed significantly greater activity than single manganese or copper oxide, or mixed oxides with other compositions [7]. Similar results were also reported by Morales et al [9], while Zimowska et al [10] examined the catalytic activities of Cu-Mn mixed oxides prepared from the hydrotalcite-like precursors.…”

Facile preparation of 3D ordered mesoporous CuOx–CeO2 with notably enhanced efficiency for the low temperature oxidation of heteroatom-containing volatile organic compounds

“…Noble metals are catalytically more active at low temperature in comparison to other metal oxides, however they are expensive and rapid deactivation by chlorine or sulfur poisoning greatly limits their large-scale application for the elimination of S-VOCs and ClVOCs. 3,6,7 CeO 2 has recently attracted considerable attention as an efficient catalyst due to its abundant oxygen vacancy defects, high oxygen storage capacity and the relatively easy shuttle between its Ce 3+ and Ce 4+ oxidation states. [8][9][10] However, CeO 2 is deactivated quickly when used for the decomposition of Cl-VOCs due to the strong adsorption of HCl or Cl 2 on to its surface, which blocks the active sites.…”