Pt Nanoparticles on Beta zeolites for Catalytic Toluene Oxidation: Effect of the Hydroxyl Groups of Beta Zeolite**

Run Zou, Sarayute Chansai, Shaojun Xu, Bing An, Shima Zainal, Yangtao Zhou, Ruojia Xin, Pan Gao, Guangjin Hou, Carmine D'Agostino, Stuart M. Holmes, Christopher Hardacre, Yilai Jiao, Xiaolei Fan

Research output: Journal PublicationArticlepeer-review

Abstract

Stabilisation of metal species using hydroxyl-rich dealuminated zeolites is a promising method for catalysis. However, insights into the interactions between the hydroxyl groups in zeolite and noble metals and their effects on catalysis are not yet fully understood. Herein, comparative studies were conducted using Pt catalysts supported on hydroxyl-rich dealuminated Beta (deAl-Beta) and the pristine proton-form Beta (H-Beta) for catalytic oxidation of toluene. The findings suggest that during impregnation the Pt precursor (i. e., Pt(NH3)4(NO3)2) interacted with different sites on deAl-Beta and H-Beta, leading to the formation of supported Pt nanoparticles with different physicochemical properties. In detail, for H-Beta, the Pt precursor interacted with Al-OH and isolated external Si-OH sites, yielding Pt NPs with a higher Pt0 proportion of ~71 % compared to ~57 % Pt0 on deAl-Beta. Comparatively, abundant hydroxyl groups on deAl-Beta such as silanol nest and isolated internal Si-OH stabilised highly active Pt-O species. The resulting Pt/deAl-Beta exhibited improved activity and anti-coking ability than Pt/H-Beta in catalytic toluene oxidation. For example, the temperature for 50 % toluene conversion was 193 °C for Pt/deAl-Beta vs. 232 °C for Pt/H-Beta, and the coke deposition was 1.7 % vs. 6.7 % (after the 24-h longevity test), respectively. According to the toluene-temperature programmed desorption (toluene-TPD), 1H nuclear magnetic resonance (1H NMR) relaxation and in situ diffuse reflection Fourier transform spectroscopy (in situ DRIFTS) characterisation, the enhanced performance of Pt/deAl-Beta could be ascribed to (i) the active Pt-O sites stabilised by hydroxyl groups, which interact with toluene easily for conversion, and (ii) the acid-free feature of the deAl-Beta support, which avoids the formation of coke precursors (such as benzoate species) on the catalyst surface. Findings of the work can serve as the design guidelines for making effective supported metal catalysts using zeolitic carriers.

Original languageEnglish
Article numbere202300811
JournalChemCatChem
Volume15
Issue number21
DOIs
Publication statusPublished - 8 Nov 2023
Externally publishedYes

Keywords

  • Beta zeolite
  • Pt nanoparticles
  • dealumination
  • hydroxyl groups
  • toluene oxidation

ASJC Scopus subject areas

  • Catalysis
  • Physical and Theoretical Chemistry
  • Organic Chemistry
  • Inorganic Chemistry

Fingerprint

Dive into the research topics of 'Pt Nanoparticles on Beta zeolites for Catalytic Toluene Oxidation: Effect of the Hydroxyl Groups of Beta Zeolite**'. Together they form a unique fingerprint.

Cite this