A Short Review on the Catalytic Activity of Hydrotalcite-Derived Materials for Dry Reforming of Methane

Nickel-containing hydrotalcite-derived materials have been recently proposed as promising materials for methane dry reforming (DRM). Based on a literature review and on the experience of the authors, this review focuses on presenting past and recent achievements on increasing activity and stability of hydrotalcite-based materials for DRM. The use of different NiMgAl and NiAl hydrotalcite (HT) precursors, various methods for nickel introduction into HT structure, calcination conditions and promoters are discussed. HT-derived materials containing nickel generally exhibit high activity in DRM; however, the problem of preventing catalyst deactivation by coking, especially below 700 °C, is still an open question. The proposed solutions in the literature include: catalyst regeneration either in oxygen atmosphere or via hydrogasification; or application of various promoters, such as Zr, Ce or La, which was proven to enhance catalytic stability

A review on plasma-catalytic methanation of carbon dioxide – Looking for an efficient catalyst

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Catalytic activity of hydrotalcite-derived catalysts in the dry reforming of methane: on the effect of Ce promotion and feed gas composition

International audienceNi/Al and Ni/Mg/Al hydrotalcite-derived materials containing various Ni loadings were synthesized and subsequently promoted with Ce-species via adsorption from [Ce(EDTA)]− complexes. The obtained materials were characterized by elemental analysis (ICP-MS), XRD, H2-TPR, CO2-TPD, TG and low temperature N2 sorption experiments. The amount of the introduced Ce was dependent on the nickel and magnesia content in catalysts precursors, and it influenced materials properties (i.e. basicity, reducibility of Ni species) in various ways and the catalytic performance in the dry reforming of methane (DRM). The promoted catalysts showed improved performance with CH4 and CO2 conversions at 550 °C in the range of 35–55 and 35–45%, respectively. The extent of the improvement was dependent on the nickel content and the presence of magnesia. In general, Ce promotion increased materials stability by changing of the type of carbonaceous deposits. Ce modification hindered the transformation of amorphous carbonaceous deposits to graphitic carbon. The former may be easier oxidized and contribute to syngas production. Two selected catalysts were additionally tested in DRM at elevated temperatures (650 and 750 °C) and over various feed gas compositions

Low-pressure glow discharge plasma-assisted catalytic CO2 hydrogenation—The effect of metal oxide support on the performance of the Ni-based catalyst

International audienceLow-pressure, glow discharge plasma catalytic CO2 methanation was investigated in the presence of Ni/Al2O3, Ni/SiO2 and Ni/CeO2-ZrO2 catalyst. The prepared samples were characterized by ICP, XRD, low-temperature N2 sorption, H2-TPR, dielectric constant measurement and FT-IR in-situ adsorption of NO, CO and CO2. The performed characterization allowed selecting the optimal conditions of catalyst preparation as well as explaining the results of plasma-catalytic tests. The application of various supports had a significant effect on plasma properties and thus dissociation of CO2 in the gas phase. It affected plasma stability as well, which decreased with the increasing values of the dielectric constant. Ni/Al2O3 sample showed the best performance in terms of CH4 production. The positive effect on the catalytic activity in thermal CO2 methanation was observed for Ni/Al2O3 and Ni/SiO2 samples. Adsorption of probe molecules (NO, CO and CO2) performed for fresh reduced and spent catalysts allowed to get insights into plasma-catalytic reaction mechanism and to explain the effect of plasma promotion on the performance of the catalysts in thermal CO2 methanation

Ceria promotion over Ni-containing hydrotalcite-derived catalysts for CO

The catalytic activity in dry methane reforming of hydrotalcite-derived catalysts with ceria and/or nickel species introduced into hydrotalcite interlayer spaces was examined. The prepared materials were characterized (XRF, XRD, FT-IR, H2-TPR and N2 sorption) and subsequently tested in CO2 methane reforming at 550 °C. The obtained results showed that the incorporation of nickel species between hydrotalcite layers resulted in active catalyst with no sign of carbon deposition. Additionally, a beneficial effect of ceria promotion was observed. Ceria-promoted sample exhibited higher activity, stability and selectivity towards DRM, which may be explained by the formation of small Ni crystallites and prevention of the formation of inactive NiAl2O4 spinel phase

Low temperature dry methane reforming over Ce, Zr and CeZr promoted Ni–Mg–Al hydrotalcite-derived catalysts

International audienceHydrotalcite derived catalysts promoted with Ce, Zr and CeZr showed considerable activity in dry methane reforming (DMR) at low temperatures (550°C). Direct methane decomposition resulting in the extensive formation of fishbone-type carbon nanofibers was substantially inhibited in the presence of Zr. Physicochemical characterization by means of N 2 adsorption, XRD, TPR and CO 2-TPD evidenced narrower porosity and higher surface areas for the Zr-containing catalysts, together with the presence of smaller Ni particles (around 4 nm) and CO 2 preferential adsorption in weak basic sites. Such small Ni particles are inactive towards the direct methane decomposition reaction. The ability of the Zr-containing catalysts to adsorb CO 2 on weak basic sites results in the formation of active carbonate species that are able to react with methane through the DMR route. The reverse Boudouard reaction occurs simultaneously to a certain extent in the presence of Zr-promoted catalyst, since carbon nanotube formations were visible on the catalyst surface upon its utilization