Signals of Transient Response Analysis Via a Broadened Pulse Combined with A step change or An isotopic Pulse Application to CO2 Reforming of Methane over NiO/ SiO2

Etukudo, Ifiok Udeme and Ideheh, P. and Eddy, Nnabuk Okon (2020) Signals of Transient Response Analysis Via a Broadened Pulse Combined with A step change or An isotopic Pulse Application to CO2 Reforming of Methane over NiO/ SiO2. IJES, 12 (8). pp. 18-21.

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Abstract

Observed signals from a transient response analysis developed by combining a broadened pulse with a step change or an isotopic pulse. The combined method provides information about the activation of the catalyst and the catalytic reaction mechanism. The method applied to the CO2 reforming of methane over NiO/SiO2 at 8000C. The response to the broadened CH4 /CO2 ( 1:1) pulse over fresh NiO/SiO2, exhibited an induction time during which no reaction between CH4 and CO2 occurred , indicating that NiO/SiO2 had no activity. As the NiO was gradually reduced by CH4, the reforming reaction took place , indicating that Ni0 is the active site for this reaction. During the transient response to the step change to He in the broadened pulse of CH4/CO2 over reduced NiO/SiO2 catalyst at 8000C, a long CO tail was observed during the experiment; however, no such tail was noted in the response after a step change to He in the broadened pure Co pulse at 8000C. This indicates that the CO desorption is rapid and that the surface reaction between C and O species constitutes the rate- determining step of the reforming reaction. The transient response to a sharp 18O2 ( isotope) pulse introduced into the broadened CH4/C16O2 pulse indicated that , over a reduced NiO/SiO2 catalyst. 18O2 replaced some C16O2 in the reaction with CH4 to generate CO18 and that some Ni0 was oxidized to Ni18O. The long tail of CO18 indicates that carbon species reduced this NiO18 to Ni0

Item Type:	Article
Uncontrolled Keywords:	Rate Determining Step , Transient Response, broadened Pulse, Induction time, Isotopic Pulse.
Subjects:	Q Science > Q Science (General) Q Science > QD Chemistry
Divisions:	Faculty of Engineering, Science and Mathematics > School of Chemistry
Depositing User:	Mrs Hannah Akinwumi
Date Deposited:	09 Mar 2022 08:32
Last Modified:	09 Mar 2022 08:32
URI:	http://eprints.covenantuniversity.edu.ng/id/eprint/15699

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