TY - JOUR

T1 - Unravelling the Cu and Ce Effects in MnO2-Based Catalysts for Low-Temperature CO Oxidation

AU - Blinov, Egor D.

AU - Kulchakovskaya, Ekaterina V.

AU - Sokovikov, Nikolai A.

AU - Svetlichnyi, Valery A.

AU - Kulinich, Sergei A.

AU - Vodyankina, Olga V.

N1 - This research was funded by the Russian Science Foundation, grant no. 19-73-30026P, https://rscf.ru/en/project/19-73-30026/.

PY - 2025/1/22

Y1 - 2025/1/22

N2 - Cu-containing and Ce-modified OMS-2 catalysts were prepared at various calcination temperatures using the hydrothermal method and tested for low-temperature CO oxidation. The structure, chemical compositions, and physical–chemical properties of the catalysts were characterized using XRD, N2 physisorption, XRF, Raman spectroscopy, SEM, high-resolution TEM with EDX, TPR-H2, and XPS. The incorporation of Cu into the Ce-OMS-2 sample facilitated the transformation of pyrolusite into cryptomelane, as confirmed by Raman spectroscopy data. In the light-off mode, the Cu/Ce-OMS-2-300 and Cu/OMS-2 samples exhibited higher activity in low-temperature CO oxidation (T90 = 115 and 121 °C, respectively) compared to sample Cu/Ce-OMS-2-450. After a long-run stability test, the Cu/Ce-OMS-X samples demonstrated excellent performance: the T80 increased by 16% and 7% for the samples calcined at 300 °C and 450 °C, respectively, while the T80 for the Cu/OMS-2 increased by 40%. The Cu/OMS-2 and Cu/Ce-OMS-2-300 samples were found to have an increased content of nanodispersed copper sites on their surfaces. These copper sites contributed to the formation of the Cu2+-O-Mn4+ interface, which is responsible for the CO oxidation. The presence of Ce3+ in the catalyst was found to increase its stability in the presence of water vapor due to the higher reoxidation ability in comparison with Ce-free sample Cu/OMS-2.

AB - Cu-containing and Ce-modified OMS-2 catalysts were prepared at various calcination temperatures using the hydrothermal method and tested for low-temperature CO oxidation. The structure, chemical compositions, and physical–chemical properties of the catalysts were characterized using XRD, N2 physisorption, XRF, Raman spectroscopy, SEM, high-resolution TEM with EDX, TPR-H2, and XPS. The incorporation of Cu into the Ce-OMS-2 sample facilitated the transformation of pyrolusite into cryptomelane, as confirmed by Raman spectroscopy data. In the light-off mode, the Cu/Ce-OMS-2-300 and Cu/OMS-2 samples exhibited higher activity in low-temperature CO oxidation (T90 = 115 and 121 °C, respectively) compared to sample Cu/Ce-OMS-2-450. After a long-run stability test, the Cu/Ce-OMS-X samples demonstrated excellent performance: the T80 increased by 16% and 7% for the samples calcined at 300 °C and 450 °C, respectively, while the T80 for the Cu/OMS-2 increased by 40%. The Cu/OMS-2 and Cu/Ce-OMS-2-300 samples were found to have an increased content of nanodispersed copper sites on their surfaces. These copper sites contributed to the formation of the Cu2+-O-Mn4+ interface, which is responsible for the CO oxidation. The presence of Ce3+ in the catalyst was found to increase its stability in the presence of water vapor due to the higher reoxidation ability in comparison with Ce-free sample Cu/OMS-2.

KW - Cu- and/or Ce-modified MnO2 catalyst

KW - OMS-2

KW - Raman

KW - TPR-H2

KW - cryptomelane

KW - low-temperature CO oxidation

KW - nanodispersed active species

KW - pyrolusite

UR - https://www.mendeley.com/catalogue/b3e7ef90-3f0f-304e-b17f-b0c4091132d4/

UR - https://www.scopus.com/record/display.uri?eid=2-s2.0-85217541620&origin=inward&txGid=1bb99d318925ef44b126bbc0ba4c8b41

U2 - 10.3390/nano15030166

DO - 10.3390/nano15030166

M3 - Article

C2 - 39940142

VL - 15

JO - Nanomaterials

JF - Nanomaterials

SN - 2079-4991

IS - 3

M1 - 166

ER -