scholarly journals Understanding the performance and mechanism of Mg-containing oxides as support catalysts in the thermal dry reforming of methane

2018 ◽  
Vol 9 ◽  
pp. 1162-1183 ◽  
Author(s):  
Nor Fazila Khairudin ◽  
Mohd Farid Fahmi Sukri ◽  
Mehrnoush Khavarian ◽  
Abdul Rahman Mohamed

Dry reforming of methane (DRM) is one of the more promising methods for syngas (synthetic gas) production and co-utilization of methane and carbon dioxide, which are the main greenhouse gases. Magnesium is commonly applied in a Ni-based catalyst in DRM to improve catalyst performance and inhibit carbon deposition. The aim of this review is to gain better insight into recent developments on the use of Mg as a support or promoter for DRM catalysts. Its high basicity and high thermal stability make Mg suitable for introduction into the highly endothermic reaction of DRM. The introduction of Mg as a support or promoter for Ni-based catalysts allows for good metal dispersion on the catalyst surface, which consequently facilitates high catalytic activity and low catalyst deactivation. The mechanism of DRM and carbon formation and reduction are reviewed. This work further explores how different constraints, such as the synthesis method, metal loading, pretreatment, and operating conditions, influence the dry reforming reactions and product yields. In this review, different strategies for enhancing catalytic activity and the effect of metal dispersion on Mg-containing oxide catalysts are highlighted.

2021 ◽  
Vol 9 ◽  
Author(s):  
Andrea Álvarez Moreno ◽  
Tomás Ramirez-Reina ◽  
Svetlana Ivanova ◽  
Anne-Cécile Roger ◽  
Miguel Ángel Centeno ◽  
...  

Designing an economically viable catalyst that maintains high catalytic activity and stability is the key to unlock dry reforming of methane (DRM) as a primary strategy for biogas valorization. Ni/Al2O3 catalysts have been widely used for this purpose; however, several modifications have been reported in the last years in order to prevent coke deposition and deactivation of the samples. Modification of the acidity of the support and the addition of noble metal promoters are between the most reported strategies. Nevertheless, in the task of designing an active and stable catalyst for DRM, the selection of an appropriate noble metal promoter is turning more challenging owing to the lack of homogeneity of the different studies. Therefore, this research aims to compare Ru (0.50 and 2.0%) and Re (0.50 and 2.0%) as noble metal promoters for a Ni/MgAl2O4 catalyst under the same synthesis and reaction conditions. Catalysts were characterized by XRF, BET, XRD, TPR, hydrogen chemisorption (H2-TPD), and dry reforming reaction tests. Results show that both promoters increase Ni reducibility and dispersion. However, Ru seems a better promoter for DRM since 0.50% of Ru increases the catalytic activity in 10% and leads to less coke deposition.


Catalysts ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 313 ◽  
Author(s):  
Ruan Gomes ◽  
Denilson Costa ◽  
Roberto Junior ◽  
Milena Santos ◽  
Cristiane Rodella ◽  
...  

CO2 reforming of CH4 to produce CO and H2 is a traditional challenge in catalysis. This area is still very active because of the potentials offered by the combined utilization of two green-house gases. The development of active, stable, and economical catalysts remains a key factor for the exploitation of natural gas (NG) with captured CO2 and biogas to produce chemicals or fuels via syngas. The major issue associated with the dry reforming process is catalyst deactivation by carbon deposition. The development of suitable catalyst formulations is one strategy for the mitigation of coking which becomes especially demanding when noble metal-free catalysts are targeted. In this work NiLa-based catalyst obtained from perovskite precursors La1−xBaxNiO3 (x = 0.0; 0.05; 0.1 and 0.2) and NiO/La2O3 were synthesized, characterized by in situ and operando XRD and tested in the dry reforming of methane. The characterization results showed that the addition of barium promoted BaCO3 segregation and changes in the catalyst structure. This partly affected the activity; however, the incorporation of Ba improved the catalyst resistance to deactivation process. The Ba-containing and Ba-free NiLa-based catalysts performed significantly better than NiO/La2O3 catalysts obtained by wet impregnation.


MRS Advances ◽  
2020 ◽  
Vol 5 (57-58) ◽  
pp. 2961-2972
Author(s):  
P.C. Meléndez-González ◽  
E. Garza-Duran ◽  
J.C. Martínez-Loyola ◽  
P. Quintana-Owen ◽  
I.L. Alonso-Lemus ◽  
...  

In this work, low-Pt content nanocatalysts (≈ 5 wt. %) supported on Hollow Carbon Spheres (HCS) were synthesized by two routes: i) colloidal conventional polyol, and ii) surfactant-free Bromide Anion Exchange (BAE). The nanocatalysts were labelled as Pt/HCS-P and Pt/HCS-B for polyol and BAE, respectively. The physicochemical characterization of the nanocatalysts showed that by following both methods, a good control of chemical composition was achieved, obtaining in addition well dispersed nanoparticles of less than 3 nm TEM average particle size (d) on the HCS. Pt/HCS-B contained more Pt0 species than Pt/HCS-P, an effect of the synthesis method. In addition, the structure of the HCS remains more ordered after BAE synthesis, compared to polyol. Regarding the catalytic activity for the Oxygen Reduction Reaction (ORR) in 0.5 M KOH, Pt/HCS-P and Pt/HCS-B showed a similar performance in terms of current density (j) at 0.9 V vs. RHE than the benchmark commercial 20 wt. % Pt/C. However, Pt/HCS-P and Pt/HCS-B demonstrated a 6 and 5-fold increase in mass catalytic activity compared to Pt/C, respectively. A positive effect of the high specific surface area of the HCS and its interactions with metal nanoparticles and electrolyte, which promoted the mass transfer, increased the performance of Pt/HCS-P and Pt/HCS-B. The high catalytic activity showed by Pt/HCS-B and Pt/HCS-P for the ORR, even with a low-Pt content, make them promising cathode nanocatalysts for Anion Exchange Membrane Fuel Cells (AEMFC).


Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3347
Author(s):  
Arslan Mazhar ◽  
Asif Hussain Khoja ◽  
Abul Kalam Azad ◽  
Faisal Mushtaq ◽  
Salman Raza Naqvi ◽  
...  

Co/TiO2–MgAl2O4 was investigated in a fixed bed reactor for the dry reforming of methane (DRM) process. Co/TiO2–MgAl2O4 was prepared by modified co-precipitation, followed by the hydrothermal method. The active metal Co was loaded via the wetness impregnation method. The prepared catalyst was characterized by XRD, SEM, TGA, and FTIR. The performance of Co/TiO2–MgAl2O4 for the DRM process was investigated in a reactor with a temperature of 750 °C, a feed ratio (CO2/CH4) of 1, a catalyst loading of 0.5 g, and a feed flow rate of 20 mL min−1. The effect of support interaction with metal and the composite were studied for catalytic activity, the composite showing significantly improved results. Moreover, among the tested Co loadings, 5 wt% Co over the TiO2–MgAl2O4 composite shows the best catalytic performance. The 5%Co/TiO2–MgAl2O4 improved the CH4 and CO2 conversion by up to 70% and 80%, respectively, while the selectivity of H2 and CO improved to 43% and 46.5%, respectively. The achieved H2/CO ratio of 0.9 was due to the excess amount of CO produced because of the higher conversion rate of CO2 and the surface carbon reaction with oxygen species. Furthermore, in a time on stream (TOS) test, the catalyst exhibited 75 h of stability with significant catalytic activity. Catalyst potential lies in catalyst stability and performance results, thus encouraging the further investigation and use of the catalyst for the long-run DRM process.


Author(s):  
Istadi Istadi ◽  
Udin Mabruro ◽  
Bintang Ayu Kalimantini ◽  
Luqman Buchori ◽  
Didi Dwi Anggoro

<p>This paper was purposed for testing reusability and stability of calcium oxide-based catalyst (K<sub>2</sub>O/CaO-ZnO) over transesterification reaction of soybean oil with methanol to produce biodiesel. The K<sub>2</sub>O/CaO-ZnO catalyst was synthesized by co-precipitation method of calcium and zinc nitrates followed by impregnation of potassium nitrate. The fresh and used catalysts were tested after regeneration. The catalysts were characterized by Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), and BET Surface Area in order to compare the catalyst structure between the fresh and used catalysts. The catalyst testing in transesterification proses was carried out at following operating conditions, i.e. catalyst weight of 6 wt.%, oil to methanol mole ratio of 1:15, and temperature of 60 oC. In addition, metal oxide leaching of K<sub>2</sub>O/CaO-ZnO catalyst during reaction was also tested. From the results, the catalysts exhibited high catalytic activity (80% fatty acid methyl ester (FAME) yield after three-cycles of usage) and acceptable reusability after regeneration. The catalyst also showed acceptable stability of catalytic activity, even after three-cycles of usage. Copyright © 2016 BCREC GROUP. All rights reserved</p><p><em>Received: 10<sup>th</sup> November 2015; Revised: 16<sup>th</sup> January 2016; Accepted: 16<sup>th</sup> January 2016</em></p><p><strong>How to Cite</strong>: Istadi, I., Mabruro, U., Kalimantini, B.A.,  Buchori, L., Anggoro, D.D. (2016). Reusability and Stability Tests of Calcium Oxide Based Catalyst (K<sub>2</sub>O/CaO-ZnO) for Transesterification of Soybean Oil to Biodiesel. <em>Bulletin of Chemical Reaction Engineering &amp; Catalysis</em>, 11 (1): 34-39. (doi:10.9767/bcrec.11.1.413.34-39)</p><p><strong>Permalink/DOI</strong>: <a href="http://dx.doi.org/10.9767/bcrec.11.1.413.34-39">http://dx.doi.org/10.9767/bcrec.11.1.413.34-39</a></p><p> </p>


2020 ◽  
Vol 92 (4) ◽  
pp. 545-556
Author(s):  
Maslin Chotirach ◽  
Supawan Tantayanon ◽  
Duangamol Nuntasri Tungasmita ◽  
Junliang Sun ◽  
Sukkaneste Tungasmita

AbstractA novel approach of titanium nitride (TiN) incorporated into SBA-15 framework was developed using one-step hydrothermal synthesis method. TiN contents up to ~18 wt% were directly dispersed in a synthetic gel under a typical strong acidic condition. The physico-chemical characteristics and the surface properties were investigated by means of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), N2 adsorption-desorption, field emission scanning electron microscope (FESEM) equipped with energy dispersive X-ray spectroscopy (EDS), wavelength dispersive X-ray fluorescence (WDXRF) and CO2-temperature programmed desorption (CO2-TPD). The results indicated that the highly ordered mesostructured was effectively maintained with high specific surface area of 532–685 m2g−1. The basicity of the modified SBA-15 increased with rising TiN loading. These modified materials were applied as a support of Ni catalyst in dry reforming of methane (DRM). Their catalytic behavior possessed superior conversions for both CO2 and CH4 with the highest H2/CO ratio (0.83) as well as 50 % lower carbon formation, compared to bare SBA-15 support.


2020 ◽  
Vol 22 (15) ◽  
pp. 5115-5122 ◽  
Author(s):  
Samer Abdulridha ◽  
Jiuxing Jiang ◽  
Shaojun Xu ◽  
Zhaoxia Zhou ◽  
He Liang ◽  
...  

Faujasite (FAU) Y zeolite assemblies with high mesoporosity (Sext = 347 m2 g−1 and Vmeso = 0.52 cm3 g−1) were synthesised using sustainable and economic cellulose nanocrystals (CNCs) via a template-directed synthesis method.


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