Carbon Dioxide Reforming Of Methane Research Articles

Thermochemical energy storage analysis of solar driven carbon dioxide reforming of methane in SiC-foam cavity reactor

Solar energy is an abundant renewable energy source, and the use of solar energy for carbon dioxide reforming of methane (CRM) is a promising thermochemical energy storage scheme, but the reactor using the traditional powder catalyst has the disadvantages of complex encapsulation and low energy storage efficiency. In this paper, porous SiC-foam with high thermal conductivity is used to prepare Ni/CeO2–Al2O3/SiC catalyst, and then is loaded into a cavity reactor to achieve highly efficient and stable CRM under solar simulator. After a period of reaction, methane conversion rate remains high. As inlet flow rate decreases and incident energy flux rises, methane conversion rate is improved, and thermochemical energy storage efficiency first rises and then drops with maximum 31.4%. The numerical model of the cavity reactor under concentrated heat flux is established, and the simulation results are in good agreement with the experimental data. The structure of catalyst bed directly influences the heat storage performance, and the optimal bed thickness, radius and porosity are obtained. For thick bed, the reverse reaction appears in the end region of the bed, and then this region expands with bed thickness rising, so the reaction rate first increases and then decreases.

SYNGAS PRODUCTION BY DRY REFORMING AND BI-REFORMING OF METHANE OVER SOL-GEL MADE Со-Rh/AL2O3 BIMETALLIC CATALYSTS

The most important global challenge of concern for humanity is the change in the Earth's climate due to greenhouse gas (GHG) emissions. In this regard, carbon dioxide reforming of methane is once again attracting more attention as the process uses two major greenhouse gases - methane (CH4) and carbon dioxide (CO2) as feedstock. The reaction product of which is synthesis gas, which is the primary building block to produce various valuable products. Rapid catalyst deactivation due to coking makes industrial development of this process difficult. Additionally, the low H2/CO ratio in synthesis gas, usually below 1.0, limits its further utilization. To solve these issues, it is necessary to create new effective coking-resistant catalysts, improve their chemical and structural composition and preparation methods, and optimize the process conditions. In this work, 5%Co-Rh/Al2O3, a bimetallic catalyst prepared by the sol-gel method (modified Pechini method) was studied in the processes of carbon dioxide and combined steam-carbon dioxide reforming of methane. It was shown that 5%Co-Rh(98:2)/Al2O3 sol-gel catalyst had a high activity in the carbon dioxide reforming of methane. The introduction of steam into the initial CH4-CO2 feedstock allows the regulation of the composition of the produced synthesis gas depending on the amount of water. At t=8000 , the degree of methane conversion is 92.5-95.8%, carbon dioxide – 85.6-97.4%, and H2/CO ratio = 1.0-2.1 depending on the amount of steam added.

Carbon dioxide reforming of methane over modified iron-cobalt alumina catalyst: Role of promoter

BackgroundCobalt-based catalysts are widely employed in methane dry reforming but tend to deactivate quickly due to coke deposits and metal sintering. To enhance the performance, iron, a cost-effective promoter, is added, improving cobalt's metal dispersibility, reducibility, and basicity on the support. This addition accelerates carbon gasification, effectively inhibiting coke deposition. MethodsA series of iron-doped cobalt alumina MFe-5Co/Al2O3 (M= 0, 0.4, 0.8, 1, 2 wt.%) were prepared via simple incipient-wetness impregnation. The catalysts were thoroughly characterized via modern techniques including BET, XRD, H2-TPR, CO2-TPD. Significant findingsThe addition of iron had a minimal impact on the properties of γ-Al2O3, but it significantly affected the dispersibility of cobalt. At an optimal dosage of 0.8 wt.%, there was a notable decrease of 29.44% in Co3O4 particle size. However, excessive iron loading induced agglomeration of Co3O4, which was reversible. The presence of iron also resulted in a decrease in the reduction temperature of Co3O4. The material's basicity was primarily influenced by the loading of iron, reaching its highest value of 705.7 μmol CO2 g−1 in the 2Fe-5Co/Al2O3. The correlation between catalytic activity and the physicochemical properties of the material was established. The 0.8Fe-5Co/Al2O3 sample exhibited excellent performance due to the favorable dispersibility of cobalt, its reducibility, and its affordable basicity.

Catalytic Performance of Bimetallic Cobalt–Nickel/Graphene Oxide for Carbon Dioxide Reforming of Methane

The design of economical and robust catalysts is a substantial challenge for the dry reforming of methane (DRM). Monometallic nickel-based catalysts used for DRM reactions had comparable activity to noble metals. However, they turned out to be less stable during the reactions. As a continuation of the interest in synthesizing catalysts for DRM, this paper evaluates the catalytic performance of bimetallic Co–Ni catalysts regarding their synergy effect, with graphene oxide (GO) as support for the first time. The synthesized bimetallic catalysts prepared via the wet-impregnation method were characterized using N2 physisorption analysis, scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and X-ray diffraction (XRD). The catalytic test was performed in a stainless-steel tubular reactor in atmospheric conditions with a reaction temperature of 800 °C, time-on-stream (TOS) of 300 min and CH4: CO2 being fed with a ratio of 1:1. The bimetallic 10 wt%Co–10 wt%Ni/GO and 20 wt%Co–10 wt%Ni/GO catalysts had a similar BET specific surface area in N2 physisorption analysis. The XRD pattern displayed a homogeneous distribution of the Co and Ni on the GO support, which was further validated through SEM–EDX. The conversion of CO2, CH4, and H2 yield decreased with reaction time due to the massive occurrence of side reactions. High conversions for CO2 and CH4 were 94.26% and 95.24%, respectively, attained by the bimetallic 20 wt%Co–10 wt%Ni/GO catalyst after 300 min TOS, meaning it displayed the best performance in terms of activity among all the tested catalysts.

The Effectiveness of Ni-Based Bimetallic Catalysts Supported by MgO-Modified Alumina in Dry Methane Reforming

Syngas is produced through the carbon dioxide reforming of methane. The traditional nickel-based catalysts are substantially destroyed by carbon deposition. The reforming reaction was conducted in a tubular microreactor at 700 °C using bimetallic Ni catalysts supported over 37% Al2O3 and 63% MgO mixtures. The impregnation process formed the catalysts, which were subsequently examined by N2-physisorption, XRD, H2-TPR, TGA, and Raman spectroscopy. The 2.5Ni+2.5Co/37%Al2O3+63%MgO bimetallic catalyst, which displayed 72% and 76% conversions of CH4 and CO2 over the course of a seven-hour procedure, was discovered to be the most active in DRM. The bimetallic catalyst with the largest weight loss in TGA, 2.5Ni+2.5Fe-MG63, had a loss of 61.3%, a difference of 26% and 21% in the activity performance of CH4 and CO2, respectively, of the tested bimetallic Ni catalysts was recorded. The long-time of 30 h on-stream CH4 and CO2 conversion reactions for 2.5Ni+2.5Co-MG63 and 2.5Ni+2.5Ce-MG63 catalysts showed the catalysts’ high stability. The TPO analysis for the 2.5Ni+2.5Cs-MG63 catalyst showed a peak at 650 °C, attributed to the oxidation of the filamentous carbon, whereas the TPO analysis for the 2.5Ni+2.5Co-MG63 catalyst depicted a peak at 540 °C, ascribed to the presence of amorphous/graphite carbon.

Effects of MgO on Ni/Al2O3 catalysts for CO2 reforming of methane to syngas

Carbon dioxide reforming of methane (CRM) converts CH4 and CO2 greenhouse gases into syngas over nickel-based catalysts. We performed CRM in a tubular microreactor at 700 °C by using 5.0 wt.% NiO catalyst, supported over mixtures of γ-Al2O3 + x MgO (x = 20, 30, 63, and 70 wt.%). The process of impregnation was used to prepare the catalysts. For characterization, N2-physisorption, XRD, H2-TPR, TGA, and Raman spectroscopy techniques were employed. Among the examined catalysts, 5Ni/Al2O3 + 63%MgO was found the most active, where it showed ≅ 72% CH4 conversion, 73% CO2 conversion, and 0.82 H2/CO mole ratio over 7 h of reaction. The MgO modifier was the primary component, which favorably affected both Ni dispersion and stability, for the good interaction between NiO and γ-alumina. The mono-supported samples displayed the lowest total hydrogen consumption. In TGA, the 5Ni/Al2O3 + 63%MgO exhibited a significant weight decrease (40%), reflecting its activity. Furthermore, the Raman spectroscopy analysis showed that the crystallinity of the carbon over this catalyst was more pronounced than the others.

Dry Reforming of Methane over Ni-Supported SBA-15 Prepared with Physical Mixing Method by Complexing with Citric Acid

Ni-supported SBA-15 catalysts were prepared by physical mixing of Ni(NO3)2·6H2O and SBA-15 (Ni/SBA-15-M) and in the presence of citric acid as the complexing agent (Ni/SBA-15-M-C). Moreover, an Ni-supported SBA-15 catalyst was also prepared by the conventional incipient impregnation method (Ni/SBA-15-I). All the catalysts were systematically evaluated for carbon dioxide reforming of methane (CDR) at CO2/CH4 = 1.0, gas hourly space velocity of 60,000 mL·g−1·h−1, and reaction temperature of 700 °C. The characterization results show that the Ni particle size of Ni/SBA-15-M-C is significantly smaller than that of Ni/SBA-15-M due to the coordination effect of citric acid and Ni2+. Consequently, the Ni/SBA-15-M-C exhibits superior anti-coking and anti-sintering during the CDR-operated period because of the higher Ni dispersion and stronger Ni–support interaction. Compared to the Ni/SBA-15-I, the physical mixing of nickel salt and mesoporous material for preparing of Ni-based catalyst is easy to operate, although the crystal size and catalytic performance of Ni/SBA-15-C are very similar to that of Ni/SBA-15-M-I. Thus, the efficient and easily controlled catalyst structure makes the physical mixing strategy very promising for preparing highly active and stable CDR catalysts.

Mini-review on fibrous zeolite catalysts for CO2 reforming of methane

The persistent threat of climate change is brought on by extreme emissions of greenhouse gases (GHGs). Due to its advantages in converting two principal GHGs (CH4 and CO2) into a synthesis gas (H2 and CO), carbon dioxide reforming of methane has received a lot of interest. However, the main issue with a dry reforming of methane (DRM) that needs to be rapidly tackled is catalyst deactivation caused by sintering and coke formation. In this context, the development of fibrous morphological support materials has emerged as an exciting technique that has shown promise in enhancing the physicochemical characteristics of the catalyst and enabling superior catalytic activity and deactivation resistance during the reaction. The physicochemical characteristics of fibrous zeolite-supported type catalysts, including metal-support interaction, metal dispersion, particle size, surface area, and porous nature, were the main emphasis of this mini-review. Designing suitable catalysts for DRM requires a thorough examination of catalytic properties and their relationship to catalytic performance.

Reduction effect on the catalytic performances of NiAl-SPC takovite catalysts in syngas synthesis process

In the downstream of the Oil & Gas industry and decline in oil production, the NiAl-HT derived hydrotalciteis a candidate as catalyst to produce syngas in the methane dry reforming process. Hydrotalcite are lamellar compounds of general formulation[M1-x 2+ Mx 3+ (OH) 2]x+[An-] x/n .m H2Owhere the ionic or cationic character can be tuned by the choice of the metal nature and oxidation degree. NiAl-SPC samples were obtained by coprecipitation at constant alkaline pH, then the product was thermal treated at 450°C for 6h to obtain mixed oxides phases. Samples prior and after calcination were characterized by XRD, ICP, BET, FTIR, SEM, TEM, TPR, TGA/DTA and Raman. Catalysts were examined in CO2 dry reforming of methane to examine the influence and the role of the reducibility ability on the catalytic reactivity and stability of NiAl-SPC hydrotalcite generics. They were reduced at 500°C, 600°C, and 700°Cfor 1h to evaluate the effect of its morphology changes on the carbon dioxide reforming of methane carried out at 700°C versus time on stream. It was shown that the reduction conditions strongly influence the reactivity of Ni metallic active phase catalyst, catalytic selectivity and its resistance to carbone deposit for methane reforming by carbon dioxide.This study proposes a further understanding of the synthesis, effects of additives and treatment of hydrotalcite as a catalyst for the DRM reaction. This knowledge will also be beneficial for the development of catalysts for other high temperature industrial applications (ammonia cracking, alcohol to hydrogen conversion...) and for longer term applications such as drug delivery or energy storage materials.

Use of A-Site Metal Exsolution from a Hydrated Perovskite Titanate for Combined Steam and CO2 Reforming of Methane.

Metal segregation from a perovskite oxide (ABO3) usually referring to "redox metal exsolution" has recently been used for in situ preparation of a well-designed catalyst where metal nanoparticles are homogeneously and strongly embedded on perovskite scaffolds upon reduction. The exsolution concept of B-site transition metal ions has grown, but several issues such as segregation of A-site alkaline-earth metal ions (altering electronic structures of the perovskite surface, causing deformation of perovskite structures, or creating undesirable products via side reactions) and carbon formations on metal nanoparticles should be addressed for stable catalysts in greenhouse gas (CO2 or CH4) conversion. Here, we suggest a new approach to designing metal-perovskite composite catalysts via A-site metal segregation from a hydrated perovskite titanate. In situ formation of A-site-deficient hydrated CaTiO3 accompanied with Ni exsolution solids leads to ∼78 and 65% of CH4 and CO2 conversion, respectively, suppressing carbon formations and alkaline-earth metal segregations in combined steam and carbon dioxide reforming of methane at 700 °C. It would help to design active and stable metal-perovskite catalysts for energy and environmental applications.

NiO-MgO Prepared by the Complex-Decomposition Method as a Catalyst for Carbon Dioxide Reforming of Methane

The NiO-MgO solid solution has been proven to be an efficient catalyst for the carbon dioxide reforming of methane (CRM). However, the challenge is still there for the facilely controlled synthesis of the single-phase solid solution with the uniform composition, and the interactions between NiO and MgO are not consistently correlated with the CRM performance. To address these issues, in this work, the complex-decomposition method was applied to regulate the chemical and structural properties of NiO-MgO catalysts via simply changing the complexing agent, calcination temperature, and Ni/Mg molar ratio. The catalysts were comparatively evaluated for CRM under severe reaction conditions of 750 °C, 0.1 MPa, CH4/CO2 = 1, and a gas hourly space velocity of 60000 mL·g−1·h−1. Irrespective of the complexing agents investigated, NiO-MgO solid solution was exclusively formed. However, the structural and reductive properties of the NiO-MgO catalysts were strongly dependent on the complexing agent, which is reasonably explained as the varied coordinative capabilities of the complexing agent with the metal cations. Moreover, the highest CRM performance, i.e., the initial CH4 conversion of ~86% kept constant for a time-on-stream of 20 h, was achieved over the Ni0.1Mg0.9O catalyst by using glycine as the complexing agent and calcined at 800 °C. The characterization and CRM results vigorously confirmed that a good balance between the sintering and the in situ release of active metallic Ni under CRM reaction conditions was constructed over the NiO-MgO catalyst prepared using glycine as the complexing agent, leading to its highest stability. Considering the simple procedure of the complex-decomposition method and the convenient adjustment of the NiO and MgO interactions by simply changing the complexing agent and calcination temperature, the thus developed catalyst can be applied for extensive understanding the CRM mechanism, and extended for large-scale preparation.

Comparative studies on promotional effect of Pr6O11, Nd2O3 and Sm2O3 on Ni–SiO2 for pressurized carbon dioxide reforming of methane

The 7 wt% rare earth metal oxide promoted Ni–SiO2 catalysts of Ni–7Pr6O11–SiO2, Ni–7Nd2O3–SiO2, and Ni–7Sm2O3–SiO2 were prepared by the complex-decomposition method, and were comparatively evaluated for pressurized carbon dioxide reforming of methane (CRM) under severe conditions of 750 °C, 1.0 MPa, CH4/CO2 = 1, and gas hourly space velocity of 53200 mL/(g·h). The addition of rare earth metal oxide does not affect the Ni dispersion, and all of the catalysts show similarly high Ni dispersion of 16.0% ± 0.2%. As a result, all of the catalysts are highly active for pressurized CRM, the initial CH4 conversions of which approach the thermodynamic equilibrium (47.0% ± 0.2%). In contrast, a clearly favorable effect of the added rare earth metal oxide on the stability of Ni–SiO2 was revealed from the CRM results for a time-on-stream of 50 h, and the highest stability without an observable decrease in the conversions of CH4 and CO2 was obtained over Ni–7Sm2O3–SiO2. Based on the characterization results of thermogravimetric differential scanning calorimetry (TG-DSC) and transmission electron microscopy (TEM), the improved stability of Ni–7Pr6O11–SiO2, Ni–7Nd2O3–SiO2, and Ni–7Sm2O3–SiO2 for pressurized CRM was manifested mainly as the suppressed formation of carbon nanotubes over the catalyst surface, the extent of which is dependent on the specific rare earth metal oxide. Moreover, the consecutive temperature programmed surface reaction of CH4, CO2, and O2 over Ni–7Sm2O3–SiO2 vigorously reveals that the addition of Sm2O3 into Ni–SiO2 inhibits the CH4 decomposition but enhances the oxidization of the carbon species by CO2, leading to the well-balanced rates for forming and removing the coke over Ni–7Sm2O3–SiO2. These findings are not only beneficial to deeply understanding the promotional effect of rare earth metal oxides on Ni-based catalysts for CRM, but also important for extending the application of the less studied rare earth metal oxides as promoters for the metal-supported catalysts.

Application of Zeolite-Containing Catalysts for Plasma-Assisted Carbon Dioxide Reforming of Methane

Application of Zeolite-Containing Catalysts for Plasma-Assisted Carbon Dioxide Reforming of Methane

Effect of Holmium Oxide Loading on Nickel Catalyst Supported on Yttria-Stabilized Zirconia in Methane Dry Reforming.

The carbon dioxide reforming of methane has attracted attention from researchers owing to its possibility of both mitigating the hazards of reactants and producing useful chemical intermediates. In this framework, the activity of the nickel-based catalysts, supported by yttria-stabilized zirconia and promoted with holmium oxide (Ho2O3), was assessed in carbon dioxide reforming of methane at 800 °C. The catalysts were characterized by N2-physisorption, H2 temperature-programmed reduction, temperature-programmed desorption of CO2, X-ray diffraction, scanning electron microscopy (SEM) together with energy-dispersive X-ray spectroscopy, transmission electron microscopy (TEM), and thermogravimetric analysis (TGA) techniques. The effect of holmium oxide weight percent loading (0.0, 1.0, 2.0, 3,0, 4.0, and 5.0 wt %) was examined owing to its impact on the developed catalysts. The optimum loading of Ho2O3 was found to be 4.0 wt %, where the methane and carbon dioxide conversions were 85 and 91%, respectively. The nitrogen adsorption-desorption isotherms specified the mesoporous aspect of the catalysts, while the SEM images displayed a morphology of agglomerated, porous particles. The TEM images of the spent catalyst displayed the formation of multiwalled carbon nanotubes. TGA of the 4.0 wt % of Ho2O3 catalyst, experimented over 7-hour time-on-stream, displayed little weight loss (<14.0 wt %) owing to carbon formation, indicating the good resistance of the catalyst to carbon accumulation due to the enhancing ability of Ho2O3 and its adjustment of the support.

Carbon Dioxide Reforming of Methane Over Co/Al2O3 Catalysts Doped with Manganese

Carbon Dioxide Reforming of Methane Over Co/Al2O3 Catalysts Doped with Manganese

Carbon dioxide reforming of methane over zirconia promoted Ni-based double-layered hydroxides

Carbon dioxide reforming of methane over zirconia promoted Ni-based double-layered hydroxides

Sintering- and coking-resistant nickel catalysts embedded in boron nitride supported nickel aluminate spinels for dry reforming of methane

Dry reforming of methane (DRM) showed prospective to reduce greenhouse gas emissions if the sintering- and coking-resistant Ni-based catalysts were successfully developed. In this work, emergent Ni nanoparticles embedded in boron nitride supported nickel aluminate spinels were originally developed for DRM. The acidity and basicity derived from nickel aluminate spinels could enhance the decomposition of CH4 and adsorption of CO2, respectively, which provides an ensemble effect with emergent Ni nanoparticles and cooperatively enhances the intrinsic activity. Moreover, the strong metal-support interaction derived from exsolution effects as well as the increased contact interface between nickel aluminate spinels and boron nitride would suppress the metal sintering while the boron nitride could inhibit the carbon deposition. The two-dimensional Raman spectra demonstrated the deposited carbon featured with low graphitic degree in the catalysts. This work provides a novel approach for the development of sintering- and coking-resistant Ni-based catalysts for carbon dioxide reforming of methane.

Sustainable Synthesis of a Highly Stable and Coke-Free Ni@CeO2 Catalyst for the Efficient Carbon Dioxide Reforming of Methane

A facile and green synthetic strategy is developed in this paper for the construction of an efficient catalyst for the industrially important carbon dioxide reforming of methane, which is also named the dry reforming of methane (DRM). Through controlling the synthetic strategy and Ni content, a high-performance Ni@CeO2 catalyst was successfully fabricated. The catalyst showed superb efficiency for producing the syngas with high and stable conversions at prolonged operating conditions. Incorporating Ni during the ceria (CeO2) crystallization resulted in a more stable structure and smaller nanoparticle (NP) size with a more robust interaction with the support than loading Ni on CeO2 supports by the conventional impregnation method. The H2/CO ratio was almost 1.0, indicating the promising applicability of utilizing the obtained syngas for the Fischer–Tropsch process to produce worthy chemicals. No carbon deposits were observed over the as-synthesized catalyst after operating the DRM reaction for 50.0 h, even at a more coke-favoring temperature (700 °C). Owing to the superb resistance to coke and sintering, control of the size of the Ni-NPs, uniform dispersion of the active phase, and potent metal interaction with the support, the synthesized catalyst achieved a magnificent catalytic activity and durability during serving for the DRM reaction for extended operating periods.

Nickel on two-dimensional ITQ-2 zeolite as a highly active catalyst for carbon dioxide reforming of methane

The physicochemical properties of the support material are important parameters that determine the activity and stability of supported metal catalysts in chemical reactions. In this study, we investigated the influence of the support dimensionality and nickel loading (5, 15, and 30 wt%) of supported-Ni catalysts for the carbon dioxide reforming of methane (CDR) by comparing the three-dimensional (3D) Ni/MCM-22 and its delaminated two-dimensional (2D) Ni/ITQ-2 catalyst. Owing to its delaminated nature, Ni/ITQ-2 exhibited a large external surface area (319 m2 g−1) and a high proportion of the nickel phyllosilicate phase, even for 30 wt% Ni loading. In addition, the strong interaction of Ni clusters with phyllosilicate resulted in a high dispersion of Ni. The 2D Ni/ITQ-2 catalysts generally exhibited a higher catalytic performance than the 3D Ni/MCM-22 catalysts. The relative proportion of the nickel phyllosilicate phase in the catalyst also played a promoting role in achieving a high catalytic performance for CDR. Unlike Ni/γ-Al2O3, Ni/ITQ-2 exhibited high conversions of CH4 and CO2, regardless of pre-reduction, which is advantageous for catalyst handling.

Effect of titania synthesis conditions on the catalytic performance of mesoporous Ni/TiO2 catalysts for carbon dioxide reforming of methane

The catalytic performance of 5 wt% Ni/TiO 2 catalysts with different physicochemical properties was studied for the CO 2 reforming of methane reaction. The TiO 2 supports were prepared by the evaporation-induced self-assembly method using three different titania metal precursors. The catalysts were characterized by XRD, BET, TGA, and TEM techniques. The results showed that the phase composition of TiO 2 support plays a crucial role in catalyst performance. Furthermore, the variation of synthesis conditions significantly affects the physicochemical properties of TiO 2 support. NH 3 -treatment helped maintain the higher surface area by retaining a significant fraction of the amorphous content of titania support. Catalysts deactivation was caused by the phase transformation of TiO 2 from anatase to rutile and the sintering of Ni metal. Phase transformation into rutile was more significant, with the catalysts possessing a higher content of amorphous TiO 2 . Ni/TiO 2 catalyst prepared using the titanium ethoxide precursor performed better in the dry reforming reaction. Anatase titania offers strong metal-support interaction, whereas weak metal-support interaction was observed in the amorphous and rutile phase. • TiO 2 support samples of distinctive physicochemical properties were prepared by varying the synthesis conditions. • Effect of Physico-chemical properties of Ni/TiO 2 catalysts was observed for the dry reforming reaction. • The Ni/TiO 2 catalyst synthesized from titanium ethoxide precursor showed good coke resistance. • The amorphous TiO 2 phase showed low metal-support interaction. • The phase content and the textural properties of TiO 2 can be tuned by varying the synthesis conditions.