In:
Catalysis Science & Technology, Royal Society of Chemistry (RSC), Vol. 11, No. 24 ( 2021), p. 7850-7865
Abstract:
CeO 2 -supported NiO x catalysts have been widely studied in various catalytic reactions including NO reduction by CO. This work is mainly focused on investigation of the impact of catalyst synthesis conditions ( e.g. , oxidation and reduction) on the physicochemical properties of NiO x /CeO 2 catalysts and the catalytic response for the NO reduction by CO reaction. The oxide NiO x /CeO 2 sample was prepared by an incipient wetness impregnation (IWI) method and reduced under hydrogen reduction treatment at high temperatures (500 and 700 °C). The physicochemical properties of the synthesized samples were characterized by BET analysis, Raman spectroscopy, XRD, XPS, EELS and high-resolution transmission electron microscopy (HR-TEM). The results showed that higher reduction temperature led to the decrease in specific surface area (SSA), fewer oxygen vacancy/defect site, larger crystallite size of the CeO 2 support, and formation of metallic Ni on the surface. The oxidized NiO x /CeO 2 catalyst showed the highest catalytic activity, indicating that the presence of oxygen vacancy/defect sites, Ni 2+ oxidation state, and smaller crystallite size are believed to enhance the catalytic activity. In situ DRIFTS confirmed the generation of several intermediate species, such as nitrate, carbonate, and N 2 O. On the basis of in situ DRIFTS and activity results, the possible reaction mechanism of NO reduction by CO over NiO x /CeO 2 was proposed.
Type of Medium:
Online Resource
ISSN:
2044-4753
,
2044-4761
Language:
English
Publisher:
Royal Society of Chemistry (RSC)
Publication Date:
2021
detail.hit.zdb_id:
2595090-3
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