Electron microscopic studies of natural gas oxidation catalyst – Effects of thermally accelerated aging on catalyst microstructure

Research output: Contribution to journalArticleScientificpeer-review

Researchers

  • Mari Honkanen
  • Thomas W. Hansen
  • Hua Jiang

  • Marja Kärkkäinen
  • Mika Huuhtanen
  • Olli Heikkinen
  • Kauko Kallinen
  • Jouko Lahtinen

  • Riitta L. Keiski
  • Jakob B. Wagner
  • Minnamari Vippola

Research units

  • Tampere University of Technology
  • Danmarks Tekniske Universitet
  • University of Oulu
  • Dinex Ecocat Oy

Abstract

Structural changes of PtPd nanoparticles in a natural gas oxidation catalyst were studied at elevated temperatures in air and low-oxygen conditions and in situ using environmental transmission electron microscopy (ETEM). The fresh catalyst shows <5 nm, PtPdOx particles on the γ-Al2O3 support. At 700 °C, the noble metal oxide decomposes and Pt gets trapped by PdO particles followed by formation of metallic Pd and Pt containing particles. At 1000 °C, the particles had a metallic Pd and Pt containing core surrounded by PdO particles. In addition, the presence of <10 nm sized particles was always observed. The activity measurements indicate the decrease in activity at the elevated temperatures. ETEM studies showed significant mobility of the noble metal particles above 850 °C. Above 1100 °C, PtPd particles were mobile and smaller particles were trapped by larger ones by a particle coalescence mechanism.

Details

Original languageEnglish
Pages (from-to)19-29
Number of pages11
JournalJournal of Catalysis
Volume349
Publication statusPublished - 1 May 2017
MoE publication typeA1 Journal article-refereed

    Research areas

  • Environmental transmission electron microscope, Low-oxygen conditions, Natural gas oxidation, Palladium, Platinum, Sintering, Thermal aging

ID: 11608951