Interactions of methane and carbon monoxide with platinum - Supported catalysts and chemical sensors
Doktorsavhandling, 2010

This thesis aims at increasing the understanding of the interactions of methane and carbon monoxide with platinum in connection to catalysis and sensor technology for emission control. Specifically, the low-temperature oxidation of methane and carbon monoxide over supported platinum catalysts and the sensor response mechanism towards CO of platinum-based chemical field effect sensors were studied. Flow-reactor experiments and in situ spectroscopic methods (mainly FTIR and energy dispersive XAS) in combination with mass spectrometry were employed at both steady-state and transient reaction conditions. The results show that the support material for platinum has a considerable impact on the low-temperature activity for oxidation of both CO and methane in oxygen excess. Under such conditions methane oxidation over platinum is generally low due to oxygen-poisoning, hindering the dissociative adsorption of methane. However, by employing transient operation of the feed-gas composition, the activity for methane oxidation can be substantially increased. A new method was developed and applied for analysis of in situ XAS spectra. It was found that transient operation of the feed-gas affects the surface composition of reactants and the state of the catalyst surface. At low temperatures, the CO oxidation reaction often suffers from self-poisoning by carbon monoxide. By supplying oxygen to the reaction through alternative routes, e.g. via additional compounds or via the support material, the low-temperature activity for CO oxidation can be significantly increased. Further, the CO coverage and the reduction of oxygen from the surface of platinum-based field effect sensors were found to be important factors in the sensing mechanism towards carbon monoxide of such devices.

Periodic operation In situ spectroscopy

XAS

CO

Sensing mechanism

Low-temperature activity

XANES

Pt

Environmental catalysis

Support material

CH4

Chemical sensors

KC
Opponent: James J. Spivey

Författare

Elin Becker

Kompetenscentrum katalys (KCK)

Chalmers, Kemi- och bioteknik, Teknisk ytkemi

Methane oxidation over alumina and ceria supported platinum

Topics in Catalysis,; Vol. 52(2009)p. 1957-1961

Artikel i vetenskaplig tidskrift

Methane oxidation over alumina supported platinum investigated by time-resolved in situ XANES spectroscopy

Journal of Catalysis,; Vol. 252(2007)p. 11-17

Artikel i vetenskaplig tidskrift

Ämneskategorier

Kemiteknik

Annan kemiteknik

ISBN

978-91-7385-379-8

Doktorsavhandlingar vid Chalmers tekniska högskola. Ny serie: 3060

KC

Opponent: James J. Spivey

Mer information

Skapat

2017-10-08