Low-temperature oxidation of ethanol over a Mn0.6Ce0.4O2 mixed oxide

Stability improvement of ZrO2-doped MnCeOx catalyst in ethanol oxidation

“…1 shows the XRD patterns of the oxides. The Mn 0.6 Ce 0.4 O x sample showed broad diffraction lines of cubic fluorite ceria (PDF# 43-1002) but without diffraction lines of manganese oxides [3]. ZrO 2 -doping weakened the reflection intensity of cubic fluorite structure and caused the Bragg angle shift to a slightly higher value.…”

“…5b, there was an induction period of about 20 h, especially in the case of the Mn 0.6 Ce 0.4 O x catalyst. This is caused by the restructuring of the catalyst under reaction conditions that lowered the mobility of oxygen species for further oxidizing acetaldehyde, resulting in decreased selectivity of CO 2 but increased selectivity towards acetaldehyde [3]. Thereafter, the conversion of ethanol and the selectivities of acetaldehyde and CO 2 remained stable for the rest 100 h. On the Mn 0.6 Ce 0.2 Zr 0.2 O x oxide, the conversion of ethanol kept at almost 100%, and the selectivity of CO 2 only slightly decreased from 99.7% to 97.8% while the selectivity of acetaldehyde increased from practically zero to about 1% (with about 1% selectivity of CO).…”

“…To determine the exact concentration of carbon oxides, a nickel catalyst converter was placed before the FID and used for converting CO and CO 2 quantitatively into methane in the presence of hydrogen. Typically, the reaction data were obtained by operating the reaction at desired temperatures for 3 h. The conversion of ethanol and the selectivity of the product were calculated on the basis of carbon-atom number balance in the product as described elsewhere [3]. Fig.…”

“…Improving the oxidation ability of the currently used three-way-catalysts (TWCs) towards these toxic oxygenates is of great importance in practical applications [2]. MnO x -CeO 2 oxides have been proved to be highly active for the oxidation of light oxygenates [3,4], but they tend to sinter at high temperatures, resulting in severe phase segregation. Doping zirconia to ceria materials have been typically used for promoting the oxygen storage capacity (OSC) and the thermal stability by forming solid solution [5][6][7].…”

“…For instance, high-temperature aged Mn 0.1 Ce 0.6 Zr 0.3 O x catalyzed ethanol oxidation more easily than the Mn 0.1 Ce 0.9 O x system [8], although the overall reaction efficiency was not so pronounced due to the lower manganese content. We have recently reported that complete oxidation of formaldehyde [10] and ethanol [3] over MnO x -CeO 2 oxides could be achieved at 373 and 463 K, respectively. In both cases, the activation of molecular oxygen is the essential step and it necessitates the intimate interaction between MnO 2 and CeO 2 in the solid solution.…”