TY - JOUR

T1 - Crystal plane dependent dispersion of cobalt metal on metastable aluminas

AU - Yakovlev, Ilya V.

AU - Zaikovskii, Vladimir I.

AU - Kazakova, Mariya A.

AU - Papulovskiy, Evgeniy S.

AU - Lapina, Olga B.

AU - d'Espinose de Lacaillerie, Jean-Baptiste

N1 - Acknowledgements: The reported study was funded by RFBR according to the research project No. 20-33-90184. This work was partially supported by the Ministry of Science and Higher Education of the Russian Federation within the governmental order for Boreskov Institute of Catalysis (project AAAA-A21-121011390054-1). NMR equipment at ESPCI Paris is funded in part by the Paris Region. I.V.Y. benefited from the Vernadski PhD fellowship from the French Embassy in Moscow.

PY - 2023/5

Y1 - 2023/5

N2 - Metallic Co nanoparticles, widely used and studied as supported heterogeneous catalysts for Fischer-Tropsch synthesis (FTS), display catalytic properties that can vary significantly depending on their size and crystal structure. In this work, we used 59Co Internal Field NMR (59Co IF NMR) complemented by high-resolution transmission electron microscopy (HRTEM) to demonstrate the influence of strong metal-support interaction on two noticeably different metastable alumina phases - γ-Al2O3 and χ-Al2O3. According to 59Co IF NMR and HRTEM, the metallic particles supported on χ-Al2O3 were larger and displayed a significantly higher content of Co in its hcp phase, which is known to be more active and selective to C5+ in FTS. The 1H NMR chemical shifts of hydroxyl groups anchored to the (1 1 0) and (1 1 1) spinel crystal planes were calculated by DFT. It revealed that the hydroxyl coverage of γ-Al2O3 facilitates the dispersion of Co precursor over the surface of the support, ultimately leading to the formation of smaller metal Co nanoparticles on γ-Al2O3 than on χ-Al2O3.

AB - Metallic Co nanoparticles, widely used and studied as supported heterogeneous catalysts for Fischer-Tropsch synthesis (FTS), display catalytic properties that can vary significantly depending on their size and crystal structure. In this work, we used 59Co Internal Field NMR (59Co IF NMR) complemented by high-resolution transmission electron microscopy (HRTEM) to demonstrate the influence of strong metal-support interaction on two noticeably different metastable alumina phases - γ-Al2O3 and χ-Al2O3. According to 59Co IF NMR and HRTEM, the metallic particles supported on χ-Al2O3 were larger and displayed a significantly higher content of Co in its hcp phase, which is known to be more active and selective to C5+ in FTS. The 1H NMR chemical shifts of hydroxyl groups anchored to the (1 1 0) and (1 1 1) spinel crystal planes were calculated by DFT. It revealed that the hydroxyl coverage of γ-Al2O3 facilitates the dispersion of Co precursor over the surface of the support, ultimately leading to the formation of smaller metal Co nanoparticles on γ-Al2O3 than on χ-Al2O3.

UR - https://www.scopus.com/record/display.uri?eid=2-s2.0-85150801546&origin=inward&txGid=6510ac9b2ac6857ca2f0ae6366db60d1

UR - https://www.mendeley.com/catalogue/23d330b8-6b41-37cb-b186-c565cda6a2e5/

U2 - 10.1016/j.jcat.2023.03.018

DO - 10.1016/j.jcat.2023.03.018

M3 - Article

VL - 421

SP - 210

EP - 220

JO - Journal of Catalysis

JF - Journal of Catalysis

SN - 0021-9517

ER -