Heteropolyacids supported on zirconia-doped γ, θ and α alumina: A physicochemical assessment and characterisation of supported solid acids

Luke Forster, Zhipeng Qie, Min Hu, Aristarchos Mavridis, Cameron Price, Christopher M.A. Parlett, Xiaolei Fan, Carmine D'Agostino

Research output: Journal PublicationArticlepeer-review

Abstract

In this paper we carry out a surface study of promising supported solid acid catalysts commonly used for the production of high value chemicals derived from glycerol. In particular, γ, θ and α alumina (Al2O3) were modified by (i) grafting with 5 wt% zirconia, (ii) doping with 30 wt% silicotungstic acid (STA), and (iii) using both zirconia and STA. The aim is to rationalise the effect of these different parameters on structural properties and surface adsorption through a comprehensive multi-technique approach, including recently developed NMR relaxation techniques. XRD and laser Raman spectroscopy confirmed a strong interaction between STA and the γ-/θ-Al2O3 resulting in a distortion of the supported STA Keggin structure relative to that of bulk STA. Conversely, a much weaker interaction between the supported STA and α-Al2O3 was measured. NMR relaxation demonstrated that the STA doping increases the adsorption properties of the catalyst, particularly for γ-/θ-Al2O3. For catalysts based on α-Al2O3, such effect was negligible. Thermogravimetric/differential thermogravimetry (TGA/DTG) analysis suggested that zirconia-grafted and non-grafted θ-Al2O3 and γ-Al2O3 are suitable materials for increasing the thermal stability of STA whereas α-Al2O3 (both grafted and non-grafted) does not improve the thermal stability of STA.

Original languageEnglish
Article number154696
JournalApplied Surface Science
Volume605
DOIs
Publication statusPublished - 15 Dec 2022
Externally publishedYes

Keywords

  • Alumina
  • Heterogeneous Catalysis
  • Heteropolyacids
  • Low-Field NMR
  • NMR Relaxation
  • Surface Chemistry

ASJC Scopus subject areas

  • Chemistry (all)
  • Condensed Matter Physics
  • Physics and Astronomy (all)
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films

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