Electronic state of silver in Ag/SiO2 and Ag/ZnO catalysts and its effect on diesel particulate matter oxidation: An XPS study

Grisel Corro*, Esmeralda Vidal, Surinam Cebada, Umapada Pal, Fortino Bañuelos, Diana Vargas, Emmanuel Guilleminot

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

100 Scopus citations

Abstract

Diesel particulate matter (DPM) oxidation activities of 3%Ag/SiO2 and 3%Ag/ZnO catalysts were investigated. The catalysts were characterized by X-ray diffraction, X-ray photoelectron spectroscopy (XPS) and diffuse reflectance spectroscopy (DRS). 3%Ag/SiO2 showed excellent activity for DPM oxidation below 300 °C. The high activity is attributed to the presence of Ag0 at the surface of SiO2, which enhances the generation of superoxide O2, the highly active species in the oxidation reactions. The activity of the catalyst did not change up to 6 oxidation cycles, indicating there is no change in electronic state of Ag during high temperature oxidation of DPM. However, 3%Ag/ZnO exhibited a very low DPM oxidation activity at the studied temperature range (25–600 °C). XPS analysis performed on the catalysts before and after their use in DPM oxidation revealed that a fraction of Ag0 in the 3%Ag/ZnO converts to Ag1+ state, probably due to the electron transfer from the Fermi level of the low work function metallic Ag to the conduction band of high band gap n-type semiconductor ZnO. We demonstrate a direct relation between the DPM oxidation activity of silver and its electronic state at the catalyst surface.

Original languageEnglish
Pages (from-to)1-10
Number of pages10
JournalApplied Catalysis B: Environmental
Volume216
DOIs
StatePublished - 2017

Bibliographical note

Publisher Copyright:
© 2017

Keywords

  • Ag catalytic site
  • Ag/SiO
  • Ag/ZnO
  • Diesel combustion
  • Diesel particulate matter oxidation

Fingerprint

Dive into the research topics of 'Electronic state of silver in Ag/SiO2 and Ag/ZnO catalysts and its effect on diesel particulate matter oxidation: An XPS study'. Together they form a unique fingerprint.

Cite this