TY - JOUR

T1 - Vanadyl Porphyrin: Efficient Spin Probe to Study the Alumina Surface of Supported Catalysts

AU - Chetkova, Anna G.

AU - Trukhan, Sergey N.

AU - Martyanov, Oleg N.

N1 - This research was funded by the Russian Science Foundation (Project No. 24-13-00208, https://rscf.ru/project/24-13-00208/ ).

PY - 2024/10

Y1 - 2024/10

N2 - The EPR method and vanadyl tetraphenylporphyrin complex (VOTPP) as a spin probe were employed to study the transformation of the γ-Al2O3 surface during temperature treatment. It has been shown that VOTPP complex is stable at least up to a temperature of 450 °C and ≲ 3 Pa. Four distinct forms of vanadyl complex were identified on the γ-Al2O3 surface, depending on the annealing temperature. The intensity ratio between these forms, exhibiting significantly different spin-Hamiltonian parameters, depend on the degree of surface hydration, which in turn determines the ratio between sites with different acidity on the γ-Al2O3 surface. It has been shown that VOTPP complex demonstrate reversible transitions between different adsorption forms on the alumina surface during dehydration/hydration cycles. The observed phenomenon can be explained by the coordination vanadyl spin probe along the axial axis to the surface centers of different polarity/acidity.

AB - The EPR method and vanadyl tetraphenylporphyrin complex (VOTPP) as a spin probe were employed to study the transformation of the γ-Al2O3 surface during temperature treatment. It has been shown that VOTPP complex is stable at least up to a temperature of 450 °C and ≲ 3 Pa. Four distinct forms of vanadyl complex were identified on the γ-Al2O3 surface, depending on the annealing temperature. The intensity ratio between these forms, exhibiting significantly different spin-Hamiltonian parameters, depend on the degree of surface hydration, which in turn determines the ratio between sites with different acidity on the γ-Al2O3 surface. It has been shown that VOTPP complex demonstrate reversible transitions between different adsorption forms on the alumina surface during dehydration/hydration cycles. The observed phenomenon can be explained by the coordination vanadyl spin probe along the axial axis to the surface centers of different polarity/acidity.

UR - https://www.scopus.com/record/display.uri?eid=2-s2.0-85198737219&origin=inward&txGid=f4e60daaa4ac0bb793a6df25d9aa4b96

UR - https://www.mendeley.com/catalogue/57b38f35-29e8-3846-899b-c9626d7f9afa/

U2 - 10.1007/s00723-024-01681-9

DO - 10.1007/s00723-024-01681-9

M3 - Article

VL - 55

SP - 1293

EP - 1306

JO - Applied Magnetic Resonance

JF - Applied Magnetic Resonance

SN - 0937-9347

IS - 10

ER -