Enhanced Long-term Stability and Carbon Resistance of Ni/MnxOy-Al2O3 Catalyst in Near-equilibrium CO2 Reforming of Methane for Syngas Production

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)2 and Mn(EDTA)2- complex in the reaction of CO2 reforming of methane. In this respect, Ni/Al2O3 and two types of Ni/MnxOy-Al2O3 catalysts 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 CO2 reforming of methane when compared to Ni/MnxOy-Al2O3 catalyst, synthesized using Mn(NO3)2 precursor. Compared to Ni/MnxOy-Al2O3, Ni/Al2O3-MnxOyY catalyst afforded near-equilibrium conversion values at 700 °C (ca. 95% conversion for CH4 and CO2, and H2/CO = 0.99 over 50 h reaction time). Also, Ni/Al2O3-MnxOyY showed more resistance to carbon formation and sintering; interestingly, after 50 h reaction time, the size of Ni0 particles in Ni/MnxOy-Al2O3 almost doubled while that of Ni/Al2O3-MnxOyY remained unchanged. The elevated conversion of CO2 and CH4 in conjunction with the observed low carbon deposition on the surface of our best catalyst (Ni/Al2O3-MnxOyY) indicated the presence of MnxOy oxide positioning mediated simultaneous in-situ carbon elimination with subsequent generation of oxygen vacant sites on the surface for more CO2 adsorption. Copyright © 2020 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).Corrigendum to this article is here: https://doi.org/10.9767/bcrec.15.3.9855.907-907

Studies of the Solvent-Free Knoevenagel Condensation over Commercial NiO compared with NiO Drived from Hydrotalcites

In this study, we compared the effect of the commercial NiO, synthesis NiAl-HT and NiO-HT drived from hydrotalcite in Knoevenagel condensation reaction. The NiAl-HT sample was synthesized by the coprecipitation method with a molar ratio M2+/M3+ = 2 at constant basic pH. X-ray Diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) were utilized to identify crystalline phases present in NiAl-HT, NiO-HT and commercial NiO. The chemical composition of the obtained solids was determined by Atomic Absorption Spectroscopy (AAS). Other techniques, such as Thermogravimetric Thermal Analyzer (TGA), Scanning Electron Microscopy (SEM) and Brunauere Emmette Teller Method (BET) were also used. As well as the BET showed the increase of the specific surface for the solid NiO-HT. The performance of the catalysts were studied in Knoevenagel condensation of benzaldehyde with ethyl acetoacetate without solvent to synthesis of organic compounds such as intermediates of dihydropyridines derivatives. The influence of different parameters, such as catalyst amount, reaction temperature and reaction time were optimized for studied the activity, the selectivity and the stability of the solids. Catalytic activity was in its lowest in the presence of NiAl-HT (26% of benzaldehyde conversion) whereas the benzaldehyde conversion increased to 77% in case of NiO-HT which can be explained by the presence of the basic sites of the NiO-HT oxides, a high surface area and a small crystallite size. Therefore, the lower increase in benzaldehyde conversion was noticed using commercial NiO (84%), perhaps owing to its high purity. A reaction mechanism is proposed by using density functional method (DFT). Copyright © 2023 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0

Efficient solar heterogeneous photocatalytic degradation of metronidazole using heterojunction semiconductors hybrid nanocomposite, layered double hydroxides

Abstract This study focuses on the synthesis of various nanocomposites with heterojunction structures, MgAl-LDH (LDH = layered double hydroxides) hybrid with semiconductor such as MoO3 and CuO. These solids were synthesized by co-precipitation method at constant pH and have been characterized extensively using atomic absorption spectroscopy (AAS), X-ray diffraction (XRD), Fourier transform infrared (FTIR) and transmission electron microscopy-energy dispersive X-ray (TEM-EDX) methods. The catalytic activity of nanocomposites was tested in the photocatalytic degradation under solar irradiation of emerging pollutants as the pharmaceutical metronidazole (MNZ). The experimental parameters, including initial MNZ concentration, the nature of oxide incorporate in the photocatalyst, catalyst loading were explored. All the synthesized samples showed high photocatalytic performances; the highest photocatalysis efficiency was achieved with the photocatalyst dose 1.5 g/L and initial MNZ concentration of 10 mg/L at neutral pH. The photocatalytic experimental results were fitted very well to the Langmuir-Hinshelwood model. From the obtained results the calcined LDH/semiconductors could be efficient for the photocatalytic process under solar irradiation of pharmaceuticals and may contribute in environmental remediation.</jats:p

Corrigendum to: Enhanced Long-term Stability and Carbon Resistance of Ni/MnxOy-Al2O3 Catalyst in Near-equilibrium CO2 Reforming of Methane for Syngas Production [15(2), 2020, 331-347]

According to Authors request (10th December 2020), Corrigendum to: Djebarri, B., Touahra, F., Aider, N., Bali, F., Sehailia, M., Chebout, R., Bachari, K., Halliche, D. (2020). Bulletin of Chemical Reaction Engineering & Catalysis, 15(2), 2020, 331-347 (doi:10.9767/bcrec.15.2.6983.331-347). First Author (Baya Djebarri) is added as member of Corresponding Author because of his largest contribution in the article and his expertise. Correction: The Authors Names were corrected to: Baya Djebarri1,*, Fouzia Touahra2,*, Nadia Aider4, Ferroudja Bali3, Moussa Sehailia2, Redouane Chebout2, Khaldoun Bachari2, Djamila Halliche3   The information detail of Corresponding Authors was corrected to: * Corresponding Authors.    Email: [email protected] (F. Touahra); [email protected] (B. Djebarri) Copyright © 2020 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0)