TY - JOUR

T1 - Comparative Study of Pd-Mayenite Catalysts Prepared via Aerogel Approaches

AU - Ilyina, Ekaterina V

AU - Bedilo, Alexander F

AU - Veselov, Grigory B

AU - Gerus, Yuri Y

AU - Shuvarakova, Ekaterina I

AU - Stoyanovskii, Vladimir O

AU - Vedyagin, Aleksey A

N1 - Funding: This study was supported by the Ministry of Science and Higher Education of the Russian Federation as part of the governmental order for Boreskov Institute of Catalysis (project no. AAAA-A21-121011390054-1).

PY - 2022/12/10

Y1 - 2022/12/10

N2 - Pd-containing catalysts based on highly dispersed aerogel-derived mayenite were prepared via two approaches. The Pd@C12A7 sample was obtained through the addition of Pd nitrate solution to a fresh Ca(OH)2-Al(OH)3 gel. Pd/C12A7 was synthesized through conventional wet impregnation of the aerogel-derived mayenite. The evolution of the textural characteristics of the support (C12A7) depending on the calcination temperature was investigated. Pd-containing samples were explored using transmission electron microscopy and spin probe EPR spectroscopy. Using the latter method, the presence of active oxygen species capable of producing nitroxyl radicals from diphenylamine was observed. The activity of these species and the reproducibility of their redox behavior were studied in three cycles of temperature-programmed reduction in both hydrogen and CO atmospheres. A prompt thermal aging technique was used to access and compare the activity of the samples towards CO oxidation. The state of Pd species before and after the aging procedure was studied via UV-Vis spectroscopy. It was found that the dispersion of PdO was higher in the case of the Pd/C12A7 catalysts compared to the Pd@C12A7 sample. This is why the Pd/C12A7 catalyst demonstrated higher activity in CO oxidation and better reducibility in TPR cycles.

AB - Pd-containing catalysts based on highly dispersed aerogel-derived mayenite were prepared via two approaches. The Pd@C12A7 sample was obtained through the addition of Pd nitrate solution to a fresh Ca(OH)2-Al(OH)3 gel. Pd/C12A7 was synthesized through conventional wet impregnation of the aerogel-derived mayenite. The evolution of the textural characteristics of the support (C12A7) depending on the calcination temperature was investigated. Pd-containing samples were explored using transmission electron microscopy and spin probe EPR spectroscopy. Using the latter method, the presence of active oxygen species capable of producing nitroxyl radicals from diphenylamine was observed. The activity of these species and the reproducibility of their redox behavior were studied in three cycles of temperature-programmed reduction in both hydrogen and CO atmospheres. A prompt thermal aging technique was used to access and compare the activity of the samples towards CO oxidation. The state of Pd species before and after the aging procedure was studied via UV-Vis spectroscopy. It was found that the dispersion of PdO was higher in the case of the Pd/C12A7 catalysts compared to the Pd@C12A7 sample. This is why the Pd/C12A7 catalyst demonstrated higher activity in CO oxidation and better reducibility in TPR cycles.

KW - CO oxidation

KW - UV–Vis spectroscopy

KW - aerogel technique

KW - mayenite

KW - palladium-containing catalysts

KW - temperature-programmed reduction

UR - https://www.scopus.com/record/display.uri?eid=2-s2.0-85144863972&origin=inward&txGid=a1481757127bda0efee7e5c6b6ad3361

UR - https://www.mendeley.com/catalogue/a2459d4c-ce9a-3c14-8913-3162e6f226af/

U2 - 10.3390/gels8120809

DO - 10.3390/gels8120809

M3 - Article

C2 - 36547333

VL - 8

JO - Gels

JF - Gels

SN - 2310-2861

IS - 12

M1 - 809

ER -