Browsing by Author "Chebout, Redouane"

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    Enhanced Long - term Stability and Carbon Resistance of Ni/Mn x O y - Al 2 O 3 Catalyst in Near - equilibrium CO 2 Reforming of Methane for Syngas Production
    (2020) Djebarri, Baya; Touahra, Fouzia; Aider, Nadia; Bali, Bali; Sehailia, Moussa; Chebout, Redouane; Bachari, Khaldoun; Halliche, Djamila
    Herein we study the catalytic activity/stability of a new generation of cheap and readily available Ni and Al-based catalysts using two Mn precursors, namely Mn(NO3)2and Mn(EDTA)2-complex in the reaction of CO2reforming of methane. In this respect, Ni/Al2O3and two types of Ni/MnxOy-Al2O3catalysts were successfully synthesized and characterized using various analytical techniques: TGA, ICP, XRD, BET, FTIR, TPR-H2, SEM-EDX, TEM, XPS, and TPO-O2. Utilization of Mn(EDTA)2-as synthetic precursor successfully furnished Ni/Al2O3-MnxOyY (Y = EDTA) catalyst which was more active during CO2reforming of methane when compared to Ni/MnxOy-Al2O3cata-lyst, synthesized using Mn(NO3)2precursor. Compared to Ni/MnxOy-Al2O3, Ni/Al2O3-MnxOyY catalyst afforded near-equilibrium conversion values at 700 °C (ca. 95% conversion for CH4and CO2, and H2/CO = 0.99 over 50 h re-action time). Also, Ni/Al2O3-MnxOyY showed more resistance to carbon formation and sintering; interestingly, after 50 h reaction time, the size of Ni0particles in Ni/MnxOy-Al2O3almost doubled while that of Ni/Al2O3-MnxOyY re-mained unchanged. The elevated conversion of CO2and CH4in conjunction with the observed low carbon deposi-tion on the surface of our best catalyst (Ni/Al2O3-MnxOyY) indicated the presence of MnxOyoxide positioning medi-ated simultaneous in-situcarbon elimination with subsequent generation of oxygen vacant sites on the surface for more CO2adsorption. Copyright © 2020 BCREC Group. All rights reserved
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    Synergistic Effect of Bimetallic Ni-Based Catalysts Derived from Hydrotalcite on Stability and Coke Resistance for Dry Reforming of Methane
    (Springer Nature, 2024) Djebarri, Baya; Aider, Nadia; Touahra, Fouzia; Chebout, Redouane; Lerari, Djahida; Bachari, Khaldoun; Halliche, Djamila
    Bimetallic Ni–Al and Ni–Fe nanoparticles catalysts derived from hydrotalcite were synthesized by co-precipitation method and applied in dry reforming of methane. The samples were calcined at 800 °C and the crystalline phases were assessed by X-ray diffraction coupled with Rietveld refinement. Other analyzes were carried out to study their textural and structural properties including, Thermogravimetric Analysis (TG), Coupled Plasma Atomic Emission Spectroscopy (ICP-AES), Brunauere-Emmette-Teller (BET), Scanning Electron Microscopy and Energy Dispersive-X-ray (SEM–EDX), Temperature Programmed Reduction (TPR), Transmission Electron Microscopy (TEM) and EDS mapping. The XRD Analyses confirmed the formation of the precursor’s layered double hydroxide structure, the formation of the γ-NiFe alloy confirmed by TEM-EDS Analysis. The specific surface area of the two samples increases after calcination, attributed to the destruction of the double-layered structure at high temperature, which produced cavities or crates resulting in larger surface areas. These catalysts were evaluated in CO2 reforming of methane under continuous flow with CH4/CO2 ratio equal to 1, at atmospheric pressure and a temperature range between 400 and 700 °C. At 700 °C, the NiAlHT catalyst displayed the best CH4 conversion (87.5%) and CO2 conversion (91.4%) compared to the conversion of CH4 (79.2%) and CO2 (84.1) for NiFeHT catalyst within 10 h stability test. The iron addition to the nickel showed improved resistance to coke deposition while a slight decrease in methane conversion was observed. The possible formation of γ-NiFe alloy observed during the study of reducibility by hydrogen was invoked to account for the catalytic behavior.