PtNi bimetallic structure supported on UiO-67 metal-organic framework (MOF) during CO oxidation

Reza Vakili, Thomas J.A. Slater, Christopher Hardacre, Alex S. Walton, Xiaolei Fan

Research output: Contribution to journalArticle

Abstract

Supported bimetallic nanoparticles (BNPs) are promising catalysts, but study on their compositional and structural changes under reaction conditions remains a challenge. In this work, the structure of PtNi BNPs supported on UiO-67 metal–organic framework (MOF) catalyst (i.e., PtNi@UiO-67) was investigated by in situ by near ambient pressure X-ray photoelectron spectroscopy (NAP-XPS). The results showed differences in the reduction behaviour of Ni species in PtNi BNPs and monometallic Ni supported on UiO-67 catalysts (i.e., PtNi@UiO-67 and Ni@UiO-67), suggesting charge transfer between metallic Pt and Ni oxides in PtNi@UiO-67. Under CO oxidation conditions, Ni oxides segregated to the outer surface of the BNPs forming a thin layer of NiOx on top of the metallic Pt (i.e., a NiOx-on-Pt structure). This resulted in a core-shell structure which was confirmed by high-resolution scanning transmission electron microscopy (HR-STEM). Accordingly, the layer of NiOx on PtNi BNPs, which is stabilised by charge transfer from metallic Pt, was proposed as the possible active phase for CO oxidation, being responsible for the enhanced catalytic activity observed in the bimetallic PtNi@UiO-67 catalyst.

Original languageEnglish
Pages (from-to)522-529
Number of pages8
JournalJournal of Catalysis
Volume391
Early online date24 Sep 2020
DOIs
Publication statusE-pub ahead of print - 24 Sep 2020

Keywords

  • Bimetallic nanoparticle catalysts (BNPs)
  • CO oxidation
  • High-resolution scanning transmission electron microscopy (HRS-TEM)
  • Metal-organic frameworks (MOFs)
  • Near-ambient pressure X-ray photoelectron spectroscopy (NAP-XPS)

ASJC Scopus subject areas

  • Catalysis
  • Physical and Theoretical Chemistry

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