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Title: Insight into the phase evolution of a NiMgAl catalyst from the reduction stage to the post-reaction stage during the dry reforming of methane [Insight into the phase evolution of NiMgAl catalyst from reduction to post-reaction for dry reforming of methane]

Abstract

Herein, phase evolution of a NiMgAl oxide catalyst at the reduction stage was qualitatively analysed and quantitatively determined by employing the continuous changes in its XRD intensity and TPR information. In conclusion, the stable crystallite size of both the active metal and spinel support was responsible for the long stability of the NiMgAl catalyst without carbon deposition during the DRM reaction.

Authors:
 [1];  [1];  [1];  [2];  [1]; ORCiD logo [1]
  1. Mississippi State Univ., Mississippi State, MS (United States)
  2. Argonne National Lab. (ANL), Argonne, IL (United States)
Publication Date:
Research Org.:
Argonne National Lab. (ANL), Argonne, IL (United States)
Sponsoring Org.:
U.S. Department of Agriculture (USDA); USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22), Scientific User Facilities Division
OSTI Identifier:
1372485
Grant/Contract Number:
AC02-06CH11357
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
ChemComm
Additional Journal Information:
Journal Volume: 53; Journal Issue: 44; Journal ID: ISSN 1359-7345
Publisher:
Royal Society of Chemistry
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY

Citation Formats

Bao, Zhenghong, Zhan, Yiqiu, Street, Jason, Xu, Wenqian, To, Filip, and Yu, Fei. Insight into the phase evolution of a NiMgAl catalyst from the reduction stage to the post-reaction stage during the dry reforming of methane [Insight into the phase evolution of NiMgAl catalyst from reduction to post-reaction for dry reforming of methane]. United States: N. p., 2017. Web. doi:10.1039/C7CC03094K.
Bao, Zhenghong, Zhan, Yiqiu, Street, Jason, Xu, Wenqian, To, Filip, & Yu, Fei. Insight into the phase evolution of a NiMgAl catalyst from the reduction stage to the post-reaction stage during the dry reforming of methane [Insight into the phase evolution of NiMgAl catalyst from reduction to post-reaction for dry reforming of methane]. United States. doi:10.1039/C7CC03094K.
Bao, Zhenghong, Zhan, Yiqiu, Street, Jason, Xu, Wenqian, To, Filip, and Yu, Fei. 2017. "Insight into the phase evolution of a NiMgAl catalyst from the reduction stage to the post-reaction stage during the dry reforming of methane [Insight into the phase evolution of NiMgAl catalyst from reduction to post-reaction for dry reforming of methane]". United States. doi:10.1039/C7CC03094K.
@article{osti_1372485,
title = {Insight into the phase evolution of a NiMgAl catalyst from the reduction stage to the post-reaction stage during the dry reforming of methane [Insight into the phase evolution of NiMgAl catalyst from reduction to post-reaction for dry reforming of methane]},
author = {Bao, Zhenghong and Zhan, Yiqiu and Street, Jason and Xu, Wenqian and To, Filip and Yu, Fei},
abstractNote = {Herein, phase evolution of a NiMgAl oxide catalyst at the reduction stage was qualitatively analysed and quantitatively determined by employing the continuous changes in its XRD intensity and TPR information. In conclusion, the stable crystallite size of both the active metal and spinel support was responsible for the long stability of the NiMgAl catalyst without carbon deposition during the DRM reaction.},
doi = {10.1039/C7CC03094K},
journal = {ChemComm},
number = 44,
volume = 53,
place = {United States},
year = 2017,
month = 5
}

Journal Article:
Free Publicly Available Full Text
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  • The mechanism of carbon formation on Ni surfaces has been studied extensively because of its importance both for coke formation on the Ni alloy reactor walls in steam cracking (pyrolysis) of naphtha or paraffinic gases in the petrochemical industry, and for catalyst deactivation in processes using supported Ni catalysts at high temperatures. Characterization of the carbon on Ni catalysts is desirable. In particular, the question whether the carbon is found only on the surface of Ni, or whether it also diffuses or dissolves in Ni, needs to be answered. Information on this is sought here from temperature programmed combustion ofmore » the carbon on/in Ni and from x-ray photoelectron spectroscopy (XPS). The very slow combustion of the C in the catalyst and an XPS study of the depth composition profile of the catalyst indicate that the C has diffused or dissolved into the bulk of Ni and a part of it is in a carbidic form.« less
  • The mechanism of the carbon dioxide reforming of methane was investigated over a nickel-on-silica catalyst. Non-steady-state and steady-state isotopic transient experiments combined with in situ DRIFT spectroscopy investigations were used to quantify the amount of the various adspecies present on the working catalyst surface. It was found that as soon as the catalyst is contacted with the reacting mixture, dehydrogenated carbon adspecies originating from the initial adsorption of methane and carbon dioxide are deposited on the nickel particles. Under steady-state reaction conditions, a permanent pool of adspecies equivalent to one monolayer of carbide-like species is continuously fed by the dissociativemore » activation of gaseous methane. This initial activation step of methane is shown to be reversible, since it allows a fast CH{sub 4}/CD{sub 4} exchange characterised by a marked isotopic effect. This pool of adspecies constitutes a reservoir of active carbon able to be oxidised into CO by oxygen atoms arising from the simultaneous carbon dioxide dissociation. This oxidation step which does not involve any C-H bond activation is assumed to be rate limiting since no kinetic isotopic effect is found for the formation of CO under the stoichiometric reforming conditions. Gaseous CO is also directly produced from the latter CO{sub 2} dissociation. Adsorption/desorption equilibria ensure a fast interconversion between gaseous CO{sub 2} and CO, as attested by their isotopic scrambling. A similar adsorption/desorption equilibrium is proposed for H{sub 2}O which, combined with the reversible activation of CO{sub 2} and CO, leads to the achieved water-gas-shift equilibrium. A particular configuration of active sites is proposed on the basis of the main mechanistic statements. 22 refs., 8 figs., 6 tabs.« less
  • The deactivation of Ni/SiO{sub 2} catalysts under the conditions of carbon dioxide reforming of methane was studied as a function of different operating parameters. Several techniques have been used: temperature programmed hydrogenation, magnetic measurements, transmission electron microscopy, and thermogravimetric analysis. It was shown that, whatever the pretreatment, nickel carbide constituted the active phase for this reaction, being established in the very initial period of operation. The reaction mixture was found to be able to reduce the nickel phase on stream. The two major aging factors, namely nickel sintering and carbon deposition, were shown to be strongly related to the pretreatedmore » conditions. A model is proposed to explain the influence of the analyzed operating parameters on the nature of the coke formation and on the changes in morphology of the nickel particles. Optimal operating conditions for the above catalyst for CO{sub 2} reforming are defined. 29 refs., 4 figs., 3 tabs.« less
  • Kinetic studies of CO{sub 2} reforming of methane over a highly active Ni/La/{alpha}-Al{sub 2}O{sub 3} catalyst were performed in an atmospheric microcatalytic fixed-bed reactor. The reaction temperature was varied between 700 and 900 C, while partial pressures of CO{sub 2} and CH{sub 4} ranged from 16 to 40 kPa. From these measurements kinetic parameters were determined; the activation energy amounted to 90 kJ/mol. The rate of CO{sub 2} reforming was described by applying a Langmuir-Hinshelwood rate equation. The developed kinetics was interpreted with a two-phase model of a fluidized bed. The predictions for a bubbling-bed reactor operated with an undilutedmore » feed (CH{sub 4}:CO{sub 2} = 1:1) at 800 C showed that, on an industrial scale, significantly longer contact times (H{sub mf} = 7.8 m, m{sub cat}/V{sub STP} = 31.8 g{center_dot}s{center_dot}ml) are necessary for achieving thermodynamic equilibrium (X{sub CH{sub 4}} = 88.2%, X{sub CO{sub 2}} = 93.6%). The performance of the reactor was strongly influenced by the interphase gas exchange: the highest space time yields were obtained for small particles (D{sub p} = 80 {micro}m).« less
  • This paper reports on bimodal nickel catalyst calcined at 873 K (B) that showed a rapid deactivation in 160 h in the steam methane reforming reaction at an atmospheric pressure; however, that calcined at 1173 K (N) showed little deactivation in 600 h. The amount of deposited carbon in N was five times as much as that in B. In B the Ni crystallite size was close to the mesopore diameter; however, in N NiAl{sub 2}O{sub 4} was formed and the Ni crystallite was smaller than that. The difference of the deactivations was presumed: a carbon block was formed inmore » a mesopore inside wall near the mouth and an opened area of the mouth was reduced. In B a thicker carbon block with the diameter of the Ni particle was formed and much reduced the opened area to the active mesopore.« less