TY - JOUR

T1 - The Catalytic Performance of CO Oxidation over MnOx-ZrO2 Catalysts: The Role of Synthetic Routes

AU - Bulavchenko, Olga A.

AU - Konovalova, Valeriya P.

AU - Saraev, Andrey A.

AU - Kremneva, Anna M.

AU - Rogov, Vladimir A.

AU - Gerasimov, Evgeny Yu

AU - Afonasenko, Tatyana N.

N1 - This work was supported by the Ministry of Science and Higher Education of the Russian Federation (Grant Agreement No. 075-15-2022-263).

PY - 2023/1

Y1 - 2023/1

N2 - MnOx-ZrO2 catalysts prepared by co-precipitation and vacuum impregnation were calcined at 400–800 °C and characterized by powder X-ray diffraction, textural studies, high-resolution transmission electron microscopy, temperature-programmed reduction, X-ray absorption near edge structure, and X-ray photoelectron spectroscopy. The catalytic activity was tested in the CO oxidation reaction. The activity of the co-precipitated samples exceeds that of the catalysts prepared by vacuum impregnation. The characterization studies showed that the nature of the active component for the catalysts obtained by co-precipitation differs from that of the catalysts obtained by impregnation. In the impregnation series, the most active catalyst was obtained at a temperature of 400 °C; its increased activity is due to the formation of MnO2 oxide nanoparticles containing Mn4+ and low-temperature reducibility. An increase in the synthesis temperature leads to the formation of less active Mn2O3, catalyst sintering, and, accordingly, deterioration of the catalytic properties. In the case of co-precipitation, the most active CO oxidation catalysts are formed by calcination at 650–700 °C in air. In this temperature interval, on the one hand, a MnyZr1−yO2−x solid solution is formed, and on the other hand, a partial separation of mixed oxide begins with the formation of highly dispersed and active MnOx. A further increase in temperature to 800 °C leads to complete decomposition of the solid solution, the release of manganese cations into Mn3O4, and a drop in catalytic activity.

AB - MnOx-ZrO2 catalysts prepared by co-precipitation and vacuum impregnation were calcined at 400–800 °C and characterized by powder X-ray diffraction, textural studies, high-resolution transmission electron microscopy, temperature-programmed reduction, X-ray absorption near edge structure, and X-ray photoelectron spectroscopy. The catalytic activity was tested in the CO oxidation reaction. The activity of the co-precipitated samples exceeds that of the catalysts prepared by vacuum impregnation. The characterization studies showed that the nature of the active component for the catalysts obtained by co-precipitation differs from that of the catalysts obtained by impregnation. In the impregnation series, the most active catalyst was obtained at a temperature of 400 °C; its increased activity is due to the formation of MnO2 oxide nanoparticles containing Mn4+ and low-temperature reducibility. An increase in the synthesis temperature leads to the formation of less active Mn2O3, catalyst sintering, and, accordingly, deterioration of the catalytic properties. In the case of co-precipitation, the most active CO oxidation catalysts are formed by calcination at 650–700 °C in air. In this temperature interval, on the one hand, a MnyZr1−yO2−x solid solution is formed, and on the other hand, a partial separation of mixed oxide begins with the formation of highly dispersed and active MnOx. A further increase in temperature to 800 °C leads to complete decomposition of the solid solution, the release of manganese cations into Mn3O4, and a drop in catalytic activity.

KW - CO oxidation

KW - catalyst

KW - fluorite

KW - manganese oxide

KW - solid solution

KW - zirconia

UR - https://www.scopus.com/record/display.uri?eid=2-s2.0-85146705500&origin=inward&txGid=d317212d3cf5d7f13fa20b0d825cc063

UR - https://www.mendeley.com/catalogue/9b7e5f5d-ce69-3549-adf7-8c0d4eb76038/

U2 - 10.3390/catal13010057

DO - 10.3390/catal13010057

M3 - Article

VL - 13

JO - Catalysts

JF - Catalysts

SN - 2073-4344

IS - 1

M1 - 57

ER -