Synergistic Effect in Ag/Fe–MnO2 Catalysts for Ethanol Oxidation

Abstract

Here we report the synergistic effect of OMS-2 catalysts tested in ethanol oxidation, and the effects produced by both the addition of an Fe modifier in the catalyst preparation stage, and the introduction of Ag on its surface by the impregnation method. To analyze the action of each component, the Fe-modified, Ag-containing OMS-2 catalysts with different Mn/Fe ratios were prepared. Combined XPS and XRF elemental analysis confirms the states and distribution of the Ag- and Fe-containing species between the surface and bulk of the OMS-2 catalysts, which form highly dispersed Ag species on the surface of 0.05Fe–OMS-2, and are also incorporated into the OMS-2 crystalline lattice. The cooperative action of Ag and Fe modifiers improves both reoxidation ability (TPO results) and the amount of adsorbed oxygen species on the catalyst surface. The introduction of Ag to the OMS-2 and 0.05 Fe–OMS-2 surface allows a high level of activity (T80 = 150–155 °C) and selectivity (SAc80 = 93%) towards the acetaldehyde formation.

The Study of Thermal Stability of Mn-Zr-Ce, Mn-Ce and Mn-Zr Oxide Catalysts for CO Oxidation

“…Thus, development of more economical, cheaper and affordable catalysts is of great importance [ 1 , 2 ]. An example of such non-noble systems can be manganese-containing compounds in the form of pristine or mixed oxides, which are widely studied as effective catalysts for the CO oxidation [ 3 , 4 ], as well as systems for soot oxidation [ 5 ], combustion of volatile organic compounds [ 6 , 7 , 8 , 9 , 10 ] and NO x removal [ 11 , 12 , 13 ]. The catalytic properties of Mn-containing systems are due to the ability of manganese to exist in the form of various stoichiometric (MnO 2 , Mn 5 O 8 , Mn 2 O 3 , Mn 3 O 4 , MnO and their polymorphs) and nonstoichiometric oxides, which are characterized by a variable oxidation state of manganese between +4 and +2 [ 14 ].…”