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

Elin Becker (Institutionen för kemi- och bioteknik, Teknisk ytkemi ; Kompetenscentrum katalys (KCK))
Göteborg : Chalmers University of Technology, 2010. ISBN: 978-91-7385-379-8.- 120 s.
[Doktorsavhandling]

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.

Nyckelord: Environmental catalysis, Low-temperature activity, Support material, Pt, CH4, CO, Periodic operation In situ spectroscopy; XAS, XANES, Chemical sensors, Sensing mechanism



Denna post skapades 2010-03-25. Senast ändrad 2013-09-25.
CPL Pubid: 118405

 

Institutioner (Chalmers)

Institutionen för kemi- och bioteknik, Teknisk ytkemi (2005-2014)
Kompetenscentrum katalys (KCK)

Ämnesområden

Kemiteknik
Annan kemiteknik

Chalmers infrastruktur

Relaterade publikationer

Inkluderade delarbeten:


Low-temperature activity for CO oxidation over diesel oxidation catalysts studied by high-throughput screening and DRIFT spectroscopy


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


Methane oxidation over alumina and ceria supported platinum


Examination

Datum: 2010-04-23
Tid: 10:15
Lokal: KC
Opponent: James J. Spivey

Ingår i serie

Doktorsavhandlingar vid Chalmers tekniska högskola. Ny serie 3060