Catalytic impact of RuOx clusters to high ammonia sensitivity of tin dioxide

Artem Marikutsa, Valery Krivetskiy, Lada Yashina, Marina Rumyantseva, Elizaveta Konstantinova, Andrea Ponzoni, Elisabetta Comini, Artem Abakumov, Alexander Gaskov

Research output: Contribution to journalArticlepeer-review

22 Citations (Scopus)

Abstract

A comparative study of NH3-sensing performance of blank and modified nanocrystalline SnO2 was performed. Tin dioxide modified by ruthenium displayed the highest ammonia sensitivity with a maximum signal at 200°C. The modifier was shown by XPS and EPR to occur in a mixed valence state of oxidized ruthenium distributed between the surface and bulk of tin dioxide nanocrystals. RuOx clustering on SnO2 surface was detected by means of electron microscopy assisted EDX-mapping. The effect of RuOx on tin dioxide interaction with ammonia was studied by temperature-programmed NH3 desorption, simultaneous Kelvin probe and DC-resistance measurements, EPR spectroscopy and analyses of the gas-solid interaction products. The modifier was shown to promote the materials reactivity to NH3 due to the catalytic activity of RuOx. The interaction with ammonia resulted in dipoles formation on the oxide surface along with reducing the grains net surface charge, established from the electron affinity increase and resistance decrease during NH3 exposure. The RuOx-catalyzed gas-solid interaction was deduced to proceed deeper than in the case of non-modified SnO2 and to yield nitrogen oxides (e.g. NO2), as was suggested by the oxidative character of gaseous products of NH3 interaction with RuOx-modified tin dioxide at 200°C.

Original languageEnglish
Pages (from-to)186-193
Number of pages8
JournalSensors and Actuators, B: Chemical
Volume175
DOIs
Publication statusPublished - Dec 2012
Externally publishedYes

Keywords

  • Ammonia sensor
  • Catalytic cluster
  • Nanocrystalline tin dioxide
  • Ruthenium
  • Surface modification

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