The promoting effect of Ce in the CO 2 methanation performances on NiUSY zeolite: A FTIR In Situ/Operando study

A. Westermann*, B. Azambre, M. C. Bacariza, I. Graça, M. F. Ribeiro, J. M. Lopes, C. Henriques

*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    56 Citations (Scopus)

    Abstract

    The behavior of 5% wt. Ni-impregnated and 5% wt. Ni-15% wt. Ce-impregnated zeolites (of USY type) were investigated by in situ/operando IR spectroscopy, both for CO 2 adsorption and under methanation conditions (H 2 :CO 2 /4:1) reaction. In situ FTIR and CO 2 -TPD experiments highlighted that CO 2 adsorption is rather poor over NiUSY zeolite, whereas CO 2 uptake over CeNiUSY leads to the formation of a large amount of adsorbed carbonates on the CeO 2 surface. Mechanistic pathways involved in CO 2 methanation over CeNiUSY catalyst are discussed in accordance with infrared spectroscopic data. Under methanation conditions, hydrogen is dissociated on Ni° particles and reacts with hydrogen and bidentate carbonates, leading first to the formation of monodentate formates, and then to methane, by further hydrogenation. No adsorbed carbonyls onto Ni° were detected while a large amount of formates was highlighted from 150 °C. The formate decomposition appears to be a kinetic relevant step to the observed kinetics of the CO 2 hydrogenation reaction.

    Original languageEnglish
    Pages (from-to)74-81
    Number of pages8
    JournalCatalysis Today
    Volume283
    Early online date12 Mar 2016
    DOIs
    Publication statusPublished - 1 Apr 2017

    Keywords

    • Carbonates
    • Ce–Ni-based zeolite
    • Formates
    • FTIR spectroscopy
    • Methane

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