Structure of Vanadia-Titania Catalysts Doped with Alkali Metals According to Solid-State NMR, ESR Spectroscopies and DFT Full article
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Catalysis Today
ISSN: 0920-5861 , E-ISSN: 1873-4308 |
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| Output data | Year: 2024, Volume: 442, Article number : 114909, Pages count : 14 DOI: 10.1016/j.cattod.2024.114909 | ||||
| Tags | Supported vanadia doped with alkali metals; 1H MAS NMR; 51V static and MAS NMR; 7Li, 23Na, 133Cs MAS NMR; ESR; DFT | ||||
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| Affiliations |
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Funding (1)
| 1 | Ministry of Science and Higher Education of the Russian Federation | FWUR-2024-0034 |
Abstract:
In this work, V/M/TiO₂ catalysts (M = Li, Na, K, Rb and Cs) were investigated with Solid-state nuclear magnetic resonance (SSNMR), electron paramagnetic resonance (ESR) and first-principles calculations. The total vanadium content corresponds to half monolayer (4 V atoms⋅nm⁻² of TiO₂ support surface), with V/M atomic ratio being 4/0.6. Static ⁵¹V and MAS ¹H, ⁷Li, ⁵¹V, ²³Na, ¹³³Cs NMR spectra were acquired. Surface moieties of vanadium oxide on (001) anatase surface were modeled using density functional theory (DFT); their ⁵¹V NMR parameters were calculated with the Gauge-Including Projected Augmented Wave (GIPAW) method and compared to experimental data obtained with ⁵¹V SSNMR spectroscopy. It was found that mainly strongly bound vanadium sites (V₃) are formed on anatase samples, located on TiO₂ terminal oxygen atoms. Weakly bound vanadium sites (V₁, V₂) are formed on bridged anatase oxygen atoms. Supported alkali metals (Li, Na, K, Rb and Cs) on TiO₂ were found to interact with protons located on the terminal and bridged TiO₂ oxygen atoms. The relative ratio of weakly bound vanadium sites (V₁, V₂) increased on alkali-containing samples. Calculations performed showed lithium cation to prefer V-O-Ti or V-O-V bonds over V=O, unsystematically deshielding vanadium nuclei. The presence of V³⁺ is likely to cause a loss of intensity in ⁵¹V NMR spectra.
Cite:
Lapina O.B.
, Papulovskiy E.S.
, Khabibulin D.F.
, Lewandowska A.E.
, Bañares M.A.
Structure of Vanadia-Titania Catalysts Doped with Alkali Metals According to Solid-State NMR, ESR Spectroscopies and DFT
Catalysis Today. 2024. V.442. 114909 :1-14. DOI: 10.1016/j.cattod.2024.114909 WOS Scopus РИНЦ AN OpenAlex
Structure of Vanadia-Titania Catalysts Doped with Alkali Metals According to Solid-State NMR, ESR Spectroscopies and DFT
Catalysis Today. 2024. V.442. 114909 :1-14. DOI: 10.1016/j.cattod.2024.114909 WOS Scopus РИНЦ AN OpenAlex
Dates:
| Submitted: | Apr 10, 2024 |
| Accepted: | Jun 24, 2024 |
| Published online: | Jul 1, 2024 |
| Published print: | Dec 1, 2024 |
Identifiers:
| Web of science: | WOS:001265714300001 |
| Scopus: | 2-s2.0-85197303382 |
| Elibrary: | 71312753 |
| Chemical Abstracts: | 2024:1493542 |
| OpenAlex: | W4400216747 |