Carbon Dioxide Reforming Of Methane Research Articles

Effects of Yb2O3 promotor on the performance of Ni/SiC catalysts in CO2 reforming of CH4

Ni/SiC and Ni-Ybx/SiC (x=2%, 4%, 6%, 10%) catalysts were prepared by the impregnation method, and the performances of catalysts in the carbon dioxide reforming of methane were studied in a fixed-bed reactor. The catalysts were characterized by BET, ICP-AES, XRD, H2-TPR, TG-DTA, XPS and TEM techniques. The experimental results indicate that the appropriate addition amount of Yb is 4% to 6%. Ni-Yb4/SiC and Ni-Yb6/SiC catalysts exhibit excellent catalytic activity and stability at 800°C, and the conversion of CH4 and CO2 can be maintained over 90% during the 100 h testing. Yb2O3 promotor can inhibit the growth of nickel nanoparticles and reduce the amount of carbon deposition, therefore Ni-Yb/SiC catalysts show stable activity in the continuous reforming reaction.

Ni/MgO catalyst prepared via dielectric-barrier discharge plasma with improved catalytic performance for carbon dioxide reforming of methane

A Ni/MgO catalyst was prepared via novel dielectric-barrier discharge (DBD) plasma decomposition method. The combined characterization of Brunauer-Emmett-Teller measurement, X-ray diffraction, hydrogen temperature-programmed reduction and transmission electron microscopy shows that DBD plasma treatment enhances the support-metal interaction of Ni/MgO catalyst and facilitates the formation of smaller Ni particles. Sphere-like Ni particles form on plasma treated Ni/MgO catalysts. The plasma treated Ni/MgO catalyst shows a significantly improved low temperature activity and good stability for CO2 reforming of methane to syngas.

Direct use of as-synthesized multi-walled carbon nanotubes for carbon dioxide reforming of methane for producing synthesis gas

Abstract In this study, laboratory prepared multi-walled carbon nanotubes (MWCNTs) over Co–Mo/MgO catalysts were used as novel nanocomposite catalysts for carbon dioxide reforming of methane (CRM). The influence of acid treatment process on the catalyst performance was thoroughly investigated. It was determined that Co–Mo/MgO present in the as-synthesized MWCNTs was responsible for high catalytic activity of the reforming reaction. The performance of the nanocomposite catalysts was compared with the conventional Co–Mo/MgO catalysts prepared by sol–gel method, revealing that MWCNTs played a supporting role in preventing catalyst deactivation. The nanocomposite catalysts gave CH 4 and CO 2 conversions of 97% and 98% , respectively, for the CRM reactions performed at 850 °C with a GHSV of 120 L/h g cat and a CH 4 /CO 2 ratio of 1 under atmospheric pressure. Stability tests, carbon deposition and characteristics of the nanocomposite catalysts were investigated up to 100 h of reaction. The proposed reaction mechanism for this catalyst shows that CH 4 decomposition and carbon gasification by CO 2 were the two important side-reactions.

Novel synthesis of nickel oxide microsphere with high surface area and its catalytic application for carbon dioxide reforming of methane

Nickel oxide (NiO) microsphere with a large surface area was novelly synthesized through nickel bicarbonate (Ni(HCO3)2) precursor. The obtained nickel oxide (NiO) microsphere was characterized by X-ray pattern diffraction, scanning electron microscopy, CO2 temperature-programmed desorption, H2 temperature-programmed reduction, N2 adsorption/desorption and laser scattering particle size distribution analyzer. It was found that nickel oxide (NiO) synthesized by the thermal decomposition of Ni(HCO3)2 through area hydrolysis, presented very nice microsphere with high surface area. The catalytic properties of obtained nickel oxide (NiO) microsphere were studied in the reaction of carbon dioxide reforming of methane where 91.3% conversion of CH4 with 93% conversion of CO2 was observed. Besides, the catalyst maintained high stability over 200 h on the stream.

Carbon dioxide reforming of methane for syngas production over Co–MgO mixed oxide nanocatalysts

Carbon dioxide reforming of methane (CH4+CO2↔2CO+2H2) was studied over nanostructure Co–MgO mixed oxide catalysts with different cobalt contents. The catalysts were prepared by co-precipitation method and characterized using XRD, BET, TEM, TPR, SEM and TPO techniques. The BET analysis showed a high specific surface area and mesoporous structure (pore sizes<15nm) and the TEM analysis indicated a nanostructure with crystallite sizes smaller than 10nm for the prepared catalysts. The obtained results revealed that the catalyst with cobalt content of 10wt.% had the highest activity and stability in dry reforming reaction.

Highly Dispersed Nickel-Containing Mesoporous Silica with Superior Stability in Carbon Dioxide Reforming of Methane: The Effect of Anchoring.

A series of nickel-containing mesoporous silica samples (Ni-SiO2) with different nickel content (3.1%–13.2%) were synthesized by the evaporation-induced self-assembly method. Their catalytic activity was tested in carbon dioxide reforming of methane. The characterization results revealed that the catalysts, e.g., 6.7%Ni-SiO2, with highly dispersed small nickel particles, exhibited excellent catalytic activity and long-term stability. The metallic nickel particle size was significantly affected by the metal anchoring effect between metallic nickel particles and unreduced nickel ions in the silica matrix. A strong anchoring effect was suggested to account for the remaining of small Ni particle size and the improved catalytic performance.

Nickel, cobalt, and Ni-Co alloy nanopowders prepared by plasma-assisted milling: Catalytic activity in the carbon dioxide reforming of methane

The nanopowders of Ni and Co metals and their alloy were prepared by plasma-assisted milling, and the activity of catalysts on their basis was studied in the carbon dioxide reforming of methane (CDRM) at atmospheric pressure. It was found that the catalytic activity of Ni nanopowder rapidly decreased because of the blocking of its surface by coking products. Co powder exhibited lower but stable activity, which gradually decreased as a result of coking only 300 h after the onset of reaction. A Ni-Co alloy (1: 1, by weight) is an active and selective catalyst for CDRM. Its catalytic activity appeared at 400°C; at 870°C, conversion reached 90% and remained unchanged for 500 h. The initial activity was restored by the regeneration of a catalyst based on the Ni-Co alloy with molecular hydrogen for several hours at 400°C.

Modifying perovskite-type oxide catalyst LaNiO3 with Ce for carbon dioxide reforming of methane

Perovskite-type oxide catalysts LaNiO3 and La1−xCexNiO3 (x ≤ 0.5) were prepared by the Pechini method and used as catalysts for carbon dioxide reforming of methane to form synthesis gas (H2 + CO). The gaseous reactants consisted of CO2 and CH4 in a molar ratio of 1:1. At a GHSV of 10,000 hr−1, CH4 conversion over LaNiO3 catalyst increased from 66% at 600 °C to 94% at 800 °C, while CO2 conversion increased from 51% to 92%. The achieved selectivities of CO and H2 were 33% and 57%, respectively, at 600 °C. To prevent the deposition of carbon and the sintering nickel species, some of the Ni in perovskite-type oxide catalyst was substituted by Ce. Ce provided lattice oxygen vacancies, which activated C–H bonds, and increased the selectivity of H2 to 61% at 600 °C. XRD analysis indicates that the catalyst exhibited a typical perovskite spinel structure and formed La2O2CO3 phases after CO2 reforming. The FE-SEM results reveal carbon whisker of the LaNiO3 catalyst and the BET analysis indicates that the specific surface area increases after the reforming reaction. The H2-TPR results confirm that Ce metals can store and provide oxygen.

Hydrogen production from carbon dioxide reforming of methane over highly active and stable MgO promoted Co–Ni/γ-Al2O3 catalyst

CoNi/Al2O3 and MgCoNi/Al2O3 catalysts are investigated for hydrogen production from CO2 reforming of CH4 reaction at the gas hourly space velocity of 40,000 mL g−1 h−1. The MgO promoted CoNi/Al2O3 catalyst shows much higher conversions (97% for CO2 and 95% for CH4 at 850 °C) than the CoNi/Al2O3 catalyst. In addition, the stability is maintained for 200 h in CO2 reforming of CH4. The outstanding catalytic activity and stability of the MgO promoted CoNi/Al2O3 catalyst is mainly due to the basic nature of MgO, an intimate interaction between Ni and the support, and rapid decomposition/dissociation of CH4 and CO2, resulting in preventing coke formation in CO2 reforming of CH4.

Effect of Ni-CNTs/mesocellular silica composite catalysts on carbon dioxide reforming of methane

In this research, the novel composite catalysts between nickel and carbon nanotubes (CNTs) over mesocellular silica (MS) support were synthesized with an attempt to improve their stability to deactivation due to coke deposition in dry reforming reaction. Accordingly, the MS support was primarily prepared based on the synthesis of SBA-15 mesoporous silica with 1,3,5-trimethylbenzene (TMB) as a pore expanding agent. After that, nickel metal was loaded onto the MS support by using an incipient-wetness impregnation method, followed by CNTs synthesis via catalytic chemical vapor deposition (CCVD) technique through tip-growth mechanism. It was found that the existence of CNTs composite catalysts with nickel metal clusters on the tips of CNTs (Ni-CNTs/MS catalysts) could significantly improve the catalyst stability in dry reforming reaction (at 650°C for 24h) and simultaneously inhibit reverse water–gas shift reaction compared to that of Ni/MS catalyst. After 24h time on stream, CO2 and CH4 conversions of Ni/MS catalyst were approximately decreased by 10%, while those of Ni-CNTs/MS catalyst were increased by 3%. This outstanding performance could be attributed to selective formation of carbon by-products as the tube-length extension of the existing CNTs. Accordingly, the active surface of Ni-CNTs/MS catalysts were remained constant throughout the period of dry reforming reaction.

CO2 reforming of CH4 over rare earth elements functionalized mesoporous Ni–Ln (Ln = Ce, La, Sm, Pr)–Al–O composite oxides

A series of rare earth elements functionalized mesoporous Ni–Ln (Ln = Ce, La, Sm, Pr)–Al–O composite oxides were originally designed and facilely synthesized via one-pot evaporation induced self-assembly (EISA) strategy. These mesoporous materials with outstanding thermal stability were investigated as the catalysts for the CO2 reforming of CH4, performing excellent catalytic activities and long-term catalytic stabilities. The “confinement effect” of the mesoporous framework matrixes contributed to stabilizing the Ni nanoparticles during the process of reaction; therefore, the serious thermal sintering of the Ni nanoparticles under severe reduction and reaction conditions was suppressed to some degree, accounting for the long catalytic stability of these mesoporous catalysts. The modification of the rare earth elements (Ce, La, Sm, Pr) played crucial roles in promoting the catalytic activities and reducing the carbon deposition. Besides, the presence of the rare earth elements also significantly influenced the distribution of the carbon species deposited over the spent catalysts. Hereby, these mesoporous Ni–Ln (Ln = Ce, La, Sm, Pr)–Al–O composite oxides promised a group of novel and stable catalyst candidates for carbon dioxide reforming of methane.

Nickel catalysts supported on MgO with different specific surface area for carbon dioxide reforming of methane

In this paper, three kinds of MgO with different specific surface area were prepared, and their effects on the catalytic performance of nickel catalysts for the carbon dioxide reforming of methane were investigated. The results showed that MgO support with the higher specific surface area led to the higher dispersion of the active metal, which resulted in the higher initial activity. On the other hand, the specific surface area of MgO materials might not be the dominant factor for the basicity of support to chemisorb and activate CO2, which was another important factor for the performance of catalysts. Herein, Ni/MgO(CA) catalyst with proper specific surface area and strong ability to activate CO2 exhibited stable catalytic property and the carbon species deposited on the Ni/MgO(CA) catalyst after 10 h of reaction at 650 °C were mainly activated carbon species.

A highly dispersed and anti-coking Ni–La2O3/SiO2 catalyst for syngas production from dry carbon dioxide reforming of methane

Download options Please wait... Supplementary files Supplementary information PDF (201K) Article information DOI https://doi.org/10.1039/C3CY00869J Article type Paper Submitted 31 Oct 2013 Accepted 23 Mar 2014 First published 24 Mar 2014 Download Citation Catal. Sci. Technol., 2014,4, 2107-2114 BibTex EndNote MEDLINE ProCite ReferenceManager RefWorks RIS Permissions Request permissions A highly dispersed and anti-coking Ni–La2O3/SiO2 catalyst for syngas production from dry carbon dioxide reforming of methane L. Mo, K. K. M. Leong and S. Kawi, Catal. Sci. Technol., 2014, 4, 2107 DOI: 10.1039/C3CY00869J To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page. If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given. If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page. Read more about how to correctly acknowledge RSC content. Social activity Tweet Share Search articles by author Liuye Mo Kerina Kai Mun Leong Sibudjing Kawi

Carbon Dioxide Reforming of Methane Over Bimetallic Co-X/Activated Carbon Catalysts (X = Ni, Cu, Fe, Mg, Ca

Carbon Dioxide Reforming of Methane Over Bimetallic Co-X/Activated Carbon Catalysts (X = Ni, Cu, Fe, Mg, Ca

Effects of Promoter on NiMgAl Catalyst Structure and Performance for Carbon Dioxide Reforming of Methane

Catalysts were prepared by adding different types of promoter (Co, Ir, or Pt) to the supported nickel catalyst NiMgAl samples. These catalysts were characterized by H2 temperature-programmed reduction (H2- TPR), CO2/CH4 temperature-programmed surface reactions (CO2/CH4-TPSR), and CO2 temperature- programmed desorption (CO2-TPD). The effects of the catalyst structure on catalytic performance in the methane dry reforming reaction with carbon dioxide were investigated. The addition of a small amount of promoter (Pt or Ir) can lower the reduction temperature of the nickel active component, and enhance performance in the methane dry reforming reaction. The catalysts with Co or Ir promoter feature lower activation energies than the unmodified NiMgAl catalyst. The activation energy was 51.8 kJ∙mol - 1 for the NiMgAl sample, decreasing to 26.4 kJ∙mol - 1 for the NiPtMgAl catalyst, which showed overall better catalytic performance. Results of CH4-TPSR and CO2-TPSR demonstrate that the NiPtMgAl catalyst can generate more active carbon species on the catalyst surface. The CO2-TPD results show that adding a promoter can increase the CO2 adsorbed/desorbed amount compared with the unmodified NiMgAl catalyst over the same reaction temperature range.

A novel study of methane-rich gas reforming to syngas and its kinetics over semicoke catalyst.

A small-size gasification unit is improved through process optimization to simulate industrial United Gas Improvement Company gasification. It finds that the reaction temperature has important impacts on semicoke catalyzed methane gas mixture. The addition of water vapor can enhance the catalytic activity of reforming, which is due to the fact that addition of water vapor not only removes carbon deposit produced in the reforming and gasification reaction processes, but also participates in gasification reaction with semicoke to generate some active oxygen-containing functional groups. The active oxygen-containing functional groups provide active sites for carbon dioxide reforming of methane, promoting the reforming reaction. It also finds that the addition of different proportions of methane-rich gas can yield synthesis gas with different H2/CO ratio. The kinetics study shows that the semicoke can reduce the activation energy of the reforming reaction and promote the occurrence of the reforming reaction. The kinetics model of methane reforming under the conditions of steam gasification over semicoke is as follows: (−74200/RT).

Carbon dioxide reforming of methane over nickel catalysts supported on mesoporous MgO

In this paper, ordered mesoporous MgO nanocrystals [MgO(M)] were synthesized, and the nickel catalysts supported on MgO(M) were facilely prepared by impregnation method. The obtained Ni/MgO(M) catalysts with advantageous textural properties were investigated as the catalysts for the carbon dioxide reforming of methane reaction. It was found that compared with the Ni/MgO(C) catalyst [MgO(C): commercial MgO], the mesoporous pore structure of MgO(M) could effectively limit the growth of the activity metal, and the Ni/MgO(M) catalysts showed high catalytic activities as well as long catalytic stabilities toward this reaction. The results showed that the conversions of CH4 and CO2 were only decreased <5 % after 100 h of reaction at 650 °C. The improved catalytic performance was suggested to be closely associated with both the advantageous structural properties, such as large specific surface area, uniform pore size, and the “confinement effect” of the mesoporous matrixes contributed to stabilize the Ni active sites during the reaction. The carbon species deposited on the spent Ni/MgO(M) catalyst were analysized by TG and Raman, and the results exhibited that the carbon species after 100 h of reaction were mainly active carbon species.

Syngas production via combined steam and carbon dioxide reforming of methane over Ni–Ce/MgAl2O4 catalysts with enhanced coke resistance

A Ni–Ce/MgAl2O4 catalyst was prepared by the co-impregnation method by adjusting the Ce/Ni ratio in a range of 0.0–1.0 for the combined steam and carbon dioxide reforming of methane (CSCRM). The characterization as to surface area, metal dispersion, NiO crystallite size as well as reduction temperature and basicity of prepared catalysts was analyzed by BET, H2-chemisroption, XRD, TPR and CO2-TPD. The used catalysts were collected to investigate the coke formation and surface characteristics through SEM, TGA, XPS and Raman analysis. The Ce addition to Ni/MgAl2O4 catalyst has significant effects on the NiO crystallite size, metal dispersion and reduction degree. The Ni–Ce/MgAl2O4 catalyst with the Ce/Ni ratio of 0.25 showed the smallest NiO crystallite size of 8.3nm and the highest metal dispersion of 4.91%. Meanwhile, in the Ni/MgAl2O4 (Ce/Ni=0) catalyst, the NiO crystallite size was found to be as large as 11.0nm and showed a low metal dispersion of 3.49%. The Ni–Ce/MgAl2O4 (Ce/Ni=0.25) catalyst shows the highest activity and coke resistance in CSCRM due to the improvement of metal dispersion, excellent reducibility as well as effective surface oxygen transfer as evidenced by XPS results.

Carbon Dioxide Reforming of Methane over Nickel Catalyst Supported on MgO(111) Nanosheets

MgO nanosheets possessing the (111) facet as the main surface were synthesized and the Ni catalyst supported on MgO(111) nanosheets was investigated for the carbon dioxide reforming of methane. The catalytic activity and carbon deposition were compared between Ni/MgO(111) and Ni/MgO(commercial) catalysts. The results showed that Ni/MgO(111) performed at a higher activity as well as a longer stability. From the characterization results, the improved catalytic performances of Ni/MgO(111) were suggested to be closely associated with both the high dispersion of active Ni particles owing to the strong metal-support interaction and the large amount of basic sites of MgO(111) due to its unusual surface properties.

Carbon dioxide reforming of methane over promoted NixMg1−xO (1 1 1) platelet catalyst derived from solvothermal synthesis

A bottom-up approach is developed to synthesize Sn, Ce, Mn, or Co promoted NixMg1−xO catalysts enclosed by Tasker III type polar (111) facets. Sn and Co are evenly distributed on NixMg1−xO, whereas Ce and Mn segregate as separate oxides. X-ray diffraction (XRD), N2 physisorption, X-ray photoelectron spectroscopy (XPS), and Transmission Electron Microscopic (TEM) measurements are carried out to understand the structure/composition of both fresh and spent catalysts. H2-Temperature Programmed Hydrogenation (TPH), XPS and Thermogravimetric analysis (TG) are employed to elucidate the types of coke formed on the spent catalysts. Mn does not show obvious enhancement to catalytic stability towards Cβ formation, and a lower activity is observed as it separates from catalyst surface and causes agglomeration of NixMg1−xO(111) platelets. Cβ and whisker carbons are found for Ce-promoted NixMg1−xO(111) catalyst, for Ce segregates as CeO2. Both Sn and Co are distinguished to enhance the coke-resistant properties of NixMg1−xO catalyst in CH4-CO2 dry reforming, as they inhibit the formation of Cβ. Activation energy (Ea) measurements show that Sn lowers the activity of Ni surfaces, while Co does not passivate the intrinsic activity of Ni surfaces. Under more critical reaction conditions with CH4/CO2 ratio of 3 and diluent gas free, Co is found to enhance the lifespan of NixMg1−xO (111) catalyst.