Influence of the Support Treatment on the Behavior of MnOx/Al2O3 Catalysts used in VOC Combustion

Abstract

Alumina was treated with water and diluted nitric acid and then was used to prepare supported MnO x / Al 2 O 3 catalysts with two different loadings. The influence of the support treatment on the catalytic behavior in ethanol and toluene combustion was studied. The treatments modified the alumina physicochemical properties (porosity, surface area, isoelectric point, and surface acidity). The modification of these properties affected the interaction of the manganese oxide species with the support and increased the dispersion of the active phase. Catalysts prepared from treated supports showed the best catalytic performance in ethanol combustion. At high manganese loading, this better catalytic performance was related to the high capacity for adsorbing oxygen. While at low manganese loading, the great amount of dispersed surface manganese oxide species and/or the existence of surface defects were relevant in the catalytic activity. On the other hand, the reactivity of the catalysts in toluene combustion was roughly correlated with the reducibility of the surface manganese oxide species. On the basis of these observations, we conclude that the ethanol combustion occurs by a suprafacial mechanism whereas the toluene combustion proceeds through an intrafacial mechanism.

Control of MnO2 nanocrystal shape from tremella to nanobelt for ehancement of the oxygen reduction reaction activity

“…The estimated O latt :O ads molar ratios ( Table 2) shows TeMnO 2 (11.0:1) > MeMnO 2 (4.9:1) > BeMnO 2 (2.2:1), indicating that oxygen vacancy density increased in the order of BeMnO 2 > MeMnO 2 > TeMnO 2 . As in previous reports [18,19], oxygen vacancy density (i.e. higher structural defect) promotes activation of oxygen molecules into active oxygen adspecies, resulting in better catalytic performance.…”

Recent Advances in the Catalytic Oxidation of Volatile Organic Compounds: A Review Based on Pollutant Sorts and Sources

“…15 For this reason, there are numerous examples of catalysts which have been investigated for the low-temperature oxidation of ethanol. Mn-based oxides and Pt supported catalysts have displayed the most potential to date, [610][611][612][613] but other transition metal (Cr, Co and Ce)-based catalysts and Au supported catalysts have also displayed some promise. [614][615][616][617][618] There are many examples of highly active MnOx based catalysts for the oxidation of ethanol documented in the literature.…”

The Design of MnOx Based Catalyst in Post-Plasma Catalysis Configuration for Toluene Abatement

“…It is well known that MnO x exhibit strong oxygen storage/release ability due to the fact that they easily undergo a rapid reduction-oxidation cycle through the interaction with reducing or oxidant agents accompany by the formation of manganese ions in various oxidation states. The involvement of lattice oxygen of catalysts in total oxidation of toluene and the strong correlation between labile lattice oxygen and catalytic activity suggest that the reaction could proceed via the MvK model [8,36]. In the case of VOCs catalytic oxidation, the first step corresponding to the reduction of the catalyst surface is generally the rate determining step [37].…”