Browsing by Author "Abdelsadek, Zoulikha"

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Examination of the Deactivation Cycle of NiAl‑ and NiMgAl‑Hydrotalcite Derived Catalysts in the Dry Reforming of Methane
(Springer, 2020) Abdelsadek, Zoulikha; Holgado, Juan P.; Halliche, Djamila; Caballero, Alfonso; Cherifi, Ouiza; Gonzalez‑Cortes, Sergio; Masset, Patrick J.
The importance of the dry reforming of methane (DRM) lies in its capability to upgrade two greenhouse gases (CH4 and CO2) into synthesis gas (CO and H2), which is one of the main building block for synthesizing hydrocarbons. However, the Ni-based catalysts for DRM reaction usually have a major catalytic stability drawback. This works aims to assess the catalytic activity and stability of two Ni-based catalysts obtained from hydrotalcite (HT) precursors (i.e., NiAl-HT and NiMgAl-HT). The precursors, calcined (-c), reduced (-R) and spent samples were characterized by a series of techniques to gain insight into the influence of MgO over Ni-based catalyst in the drying reforming of methane. An in-situ ageing cycle process to speed up the deactivation of hydrotalcite-derived catalysts showed that the NiMgAl-HTc-R catalyst displayed a higher activity and resistance to coke formation (stability) than NiAl-HTc-R because of the introduction of Mg into hydrotalcite structure in the catalyst precursor. The presence of this element enhances several factors involved in the stability of Ni-based catalysts for the DRM process such as the reducibility and textural features of the catalysts, size and dispersion of Ni0 nanoparticles and also maintains a good compromise between the acid and base properties of the solid catalysts.
Hydrogen production via methane dry reforming process over CoAl and CoMgAl-Hydrotalcite derived catalysts
(IOP Publishing, 2021) Abdelsadek, Zoulikha; Chaudhari, P.; Holgado, J. P.; Bali, F.; Halliche, D.; Cherifi, O.; Gonzalez-Cortes, S.; Masset, P. J.
Co0.67Al0.31 and Co0.14Mg0.54Al0.31 hydrotalcite based catalysts were prepared by a co-precipitation method at a fixed pH=11, exhibiting a suitable hydrotalcite structure to be used as a catalyst in the reaction of the dry reforming of methane (DRM). Calcination at 450 C provides the best conditions to prepare the most adapted structure and morphology to be later used in the DRM reaction. The samples were characterised by XRD, FTIR, SEM and it was shown that they exhibit a specific surface in the 30-70 g/cm2 and a crystallite size of approximately 20 nm. The results of the TPR analysis showed clearly that CoAl-HT has better catalytic performances than CoMgAl-HT. This result can be explained by the presence of the Co0 for the catalyst CoAl-HTc-R and the total absence in the sample CoMgAl-HTc-R. The solid CoMgAl-HTc-R requires high reduction temperature compared to CoAl-HTc-R due to the strong CoO-MgO interactions
Lanthanum-Promoted nickel-based catalysts for the dry reforming of methane at low temperatures
(Springer, 2023) Abdelsadek, Zoulikha; Köten, Hasan; Gonzalez-Cortes, Sergio; Cherifi, Ouiza; Halliche, Djamila; Masset, Patrick J.
In recent decades, considerable attention has been paid to the catalytic dry reforming of methane to obtain syngas. This reaction has very important environmental implications due to the utilization of CH4 and CO2, gases that contribute to the greenhouse effect. The dry reforming of methane is normally carried out over strong basic catalysts with noble metals. Nickel has emerged as an interesting alternative, although it tends to deactivate and form carbon whiskers, which could block the reactor. It is therefore necessary to improve their catalytic performance (conversion, selectivity and stability). In this work, Ni0.69La0.31 and Ni0.14Mg0.55La0.31 were studied in the dry methane reforming reaction. The precursors were prepared by co-precipitation and the oxide phases were obtained by calcining these precursors at 450°C/6 h. The XRD diagrams of the calcined samples show the formation of mixed oxide phases with a periclase-like structure. Analysis of the temperature-programmed reduction shows that the presence of Mg shifts the reduction to higher temperatures. The catalysts, reduced at 650°C, were tested in this reaction as a function of operating time at 650°C. No deactivation occurred after 20 h of operation. Furthermore, the combination of Mg and La drastically improves the conversion and selectivity of the catalyst (> 95%)
Mg-Fe-hydrotalcite as catalyst for the benzylation of benzene and other aromatics by benzyl chloride reactions
(Wiley Interscience, 2008) Tahir, N.; Abdelsadek, Zoulikha; Halliche, D.; Saadi, S.; Chebout, R.; Cherifi, Ouiza; Bachari, K.