Dry Reforming Of CH4 Research Articles

Integrated CO2 Capture and Dry Reforming of CH4 to Syngas: A Review.

Integrating carbon capture with dry reforming of methane offers a promising approach to addressing greenhouse gas emissions while producing valuable syngas. This review examines the complexities and progress made in this integrated process, wherein catalysts play a critical role in adsorbing carbon dioxide and facilitating the conversion of methane to syngas. The chemical process entails the concurrent capture of CO2 emissions and their usage in dry reforming, a reaction in which CH4 interacts with CO2 to generate syngas, an essential precursor for various industrial applications. The dual-functional materials can adsorb carbon dioxide and actively reform to an end-use application. The much-studied Ca-based sorbents exhibit a theoretical carbon capture capacity of 17.8 mmol g-1. However, during practical exploration of these materials as a dual-functional catalyst for integrated carbon capture and the dry reforming of methane, the uptake reduces to ∼13 mmol g-1 carbon capacity with 96.5 and 96% conversions of CO2 and CH4, respectively. Therefore, a thorough analysis of the complex relationship between CO2 capture and CH4 reforming catalysis is attempted herein based on various reported materials. Design concepts, structural optimization, and performance evaluation analysis of the dual-functional materials reveal their importance in carbon capture and reformation technology. Additionally, this review covers the field difficulties, future perspectives, and attractive commercial implementation predictions. This scrutiny illustrates the significance of dual-functional materials for sustainable energy production and environmental protection.

Dry Reforming of CH4 Using a Microreactor

In the present study, a comparison of the dry reforming of a gas mixture containing methane, carbon dioxide and nitrogen without contaminants to a ruthenium-based Ru/Al2O3 catalyst was carried out in a microreactor for the first time. The influence of the contact time, temperature and composition of the feed on the conversion was exhaustively investigated. The optimal operating conditions were found to be a contact time of 80 milliseconds, a temperature of 700 °C and a CH4:CO2 ratio of 1. The assessment of diffusional limitations reveals that there is no resistance to mass transfer, which reveals the potential benefit of the determination of intrinsic reaction kinetics within a microreactor.

Distributed electrified heating for efficient hydrogen production

This study introduces a distributed electrified heating approach that is able to innovate chemical engineering involving endothermic reactions. It enables rapid and uniform heating of gaseous reactants, facilitating efficient conversion and high product selectivity at specific equilibrium. Demonstrated in catalyst-free CH4 pyrolysis, this approach achieves stable production of H2 (530 g h−1 L reactor−1) and carbon nanotube/fibers through 100% conversion of high-throughput CH4 at 1150 °C, surpassing the results obtained from many complex metal catalysts and high-temperature technologies. Additionally, in catalytic CH4 dry reforming, the distributed electrified heating using metallic monolith with unmodified Ni/MgO catalyst washcoat showcased excellent CH4 and CO2 conversion rates, and syngas production capacity. This innovative heating approach eliminates the need for elongated reactor tubes and external furnaces, promising an energy-concentrated and ultra-compact reactor design significantly smaller than traditional industrial systems, marking a significant advance towards more sustainable and efficient chemical engineering society.

Solar driven integrated CO2 capture and CH4 dry reforming via FexMny/Ni/CaAl multi-function materials

Integrated CO2 capture and dry reforming of CH4 (ICCU-DRM) holds great promise in mitigating greenhouse gas emissions and producing value-added syngas simultaneously. However, the in-situ conversion is a highly endothermic process, which requires a large amount of energy to drive, making it very difficult for large-scale applications. The combination of solar energy in ICCU-DRM provide a potential solution to tackle the problem, but it needs to construct and evaluate multi-function materials (MFMs) with good features of CO2 adsorption, catalytic conversion and light absorption. Herein, we report a synthesis approach to prepare Fe5Mn5/Ni/CaAl for use in the solar driven ICCU-DRM, which directly utilize the solar energy for syngas production with excellent comprehensive performance. The material prepared demonstrates an average spectral absorbance of 85.81 %, and a CO2 capacity of 8.46 mmol·g−1 with up to 89 % conversion to syngas. We expect the synthesis strategy has good implications on the development of innovative materials for carbon reduction and energy storage applications.

Experimental investigation of integrated CO2 capture and conversion to syngas via calcium looping coupled with dry reforming of CH4

Calcium looping integrated with dry reforming of CH4 is a promising strategy for CO2 capture and in situ conversion to syngas. This intensified process is usually conducted with bifunctional materials that combine CO2 capture (CaO) and catalytic (Ni) active sites. Herein, the integrated calcium looping/dry reforming process was examined by investigating various bifunctional materials and operating conditions. The Ni loading of materials affected the interaction between active and inert phases, while adding a CaZrO3 promoter enhanced the CO2 capture and catalytic activities and the resistance toward sintering. Conducting experiments with a fluidized bed reactor (700 °C, 3% CH4 in feed) led to nearly complete CH4 conversion and ∼52% utilization of captured CO2 toward syngas production with steady H2/CO ratio close to unity. Temperature comprised a decisive parameter, with low values enabling high degrees of CO2 conversion up to ∼80%. The increase of CH4 concentration in the gas feedstock enhanced the rate of calcination and the conversion of CO2 over its desorption in the gas phase. Co-feeding O2 with CH4 was proposed to mitigate the energy demand, which reduced the reforming selectivity for the partial oxidation reaction and increased the H2/CO ratio of syngas.

A strategy of Co doping in MgO to significantly improve the performance of solar-driven thermocatalytic CO2 reduction on Ru/Co-MgO

Dry reforming of CH4 (DRM) driven solely by solar light provides an attractive strategy for solving energy shortages and global warming. The strategy faces two challenges: so far, high fuel productivity and solar-to-fuel efficiency (η) can only be realized at high solar intensities (usually more than 192 kW m−2). Furthermore, coking side reactions are more favorable in thermodynamically, which can lead to catalyst deactivation. Herein, a new nanocomposite of Ru nanoparticles (NPs) loaded on Co-doped MgO with reactive oxygen species and a strong optical absorption throughout the entire solar spectrum (Ru/Co-MgO) is prepared. At relatively low solar intensity (73.2 kw m−2), the solar-driven DRM on Ru/Co-MgO achieves high production rates of CO (rCO, 80.01 mmol g-1catalyst min−1) and H2 (rH2, 62.31 mmol g-1catalyst min−1) with larger η of 26.1 %, which shows an increase of 1.3-fold in rCO, rH2 and η, while a 65-fold decrease in coking rate (rC) compared to a reference catalyst of Ru and Co NPs loaded on MgO (RuCo/MgO). The significant improvement in the catalytic performance stems from the involvement of reactive oxygen (–Co–O–Mg–) in Co-MgO for the oxidation of C* species as a rate-determining step of DRM, which enhances the catalytic activity and significantly inhibits coking. Additionally, the light not only promotes the reactions both of DRM on Ru NPs and strongly adsorbed CO2 on Co-MgO with C* species at the Ru/Co-MgO interface, but also facilitates the dissociation of CO2 adsorbed on the oxygen vacancies of Ru/Co-MgO into CO, thus accelerating the synergistic effect between Ru NPs and Co-MgO.

Kinetics of thermal dry reforming of methane for syngas production and solid carbon capture

By combining numerical simulations and experiments, catalyst-free thermal dry reforming of biogas for sustainable syngas production and solid carbon capture is investigated under industrially viable conditions.

Ternary Fe- or Mo-Au-Ni/GDC as Candidate Fuel Electrodes for the Internal Dry Reforming of CH4: Physicochemical and Kinetic Investigation

The present study deals with the physicochemical and catalytic/kinetic investigation of Fe, Au, Fe-Au, and Mo-Au modified Ni/GDC electrocatalysts towards their performance for the DRM, RWGS, and CH4 decomposition reactions. For this purpose, Au-NiO/GDC (where Au = 1 or 3 wt.%), Fe-NiO/GDC (where Fe = 0.5 or 2 wt.%), 0.5Fe-3Au-NiO/GDC, and 0.4Mo-3Au-NiO/GDC were synthesized via deposition (co-) precipitation. There is discussion on the structural properties of the electrocatalysts on the oxidized and reduced state, as well as their use as electrolyte-supported (half) cells. A key remark after H2-reduction is the formation of binary or ternary solid solutions. Ni/GDC was the most active for the catalytic CO2 reforming of CH4 and the CH4 decomposition reactions and as a result the most prone to carbon deposition. On the other hand, the modified 3Au-Ni/GDC, 0.5Fe-3Au-Ni/GDC, and 0.4Mo-3Au-Ni/GDC exhibited the following properties: (i) the highest Ea,app for the non-desired RWGS reaction, (ii) high tolerance to carbon formation due to lower activity for the CH4 decomposition, and (iii) were also less active for H2 and CO production. Finally, 0.4Mo-3Au-Ni/GDC seems to perform the DRM reaction through a different mechanism when compared to Ni/GDC. Overall, the above three samples are proposed as potential fuel electrodes for further electrocatalytic measurements for the SOFC internal DRM process.

Influence of Pulse Repetition Frequency on CH4 Dry Reforming by Nanosecond Pulsed Dielectric Barrier Discharges

Influence of Pulse Repetition Frequency on CH4 Dry Reforming by Nanosecond Pulsed Dielectric Barrier Discharges

Noble Metals in Recent Developments of Heterogeneous Catalysts for CO2Conversion Processes

AbstractFollowing the advances in capture technologies, CO2utilization associated with low‐cost renewable H2in catalytic hydrogenation is a promising strategy for reducing the carbon footprint of industrial processes by providing valuable chemicals and fuels. However, the scalability and economic viability of these processes will depend on the development of efficient catalysts. Noble metal‐based catalysts have been extensively reported in the last few years as highly effective in promoting CO2hydrogenation to various products. Although promising, the scarcity, high cost, and environmental impact of mining make it challenging to scale up these materials from bench to plant. Developing advanced synthesis and characterization methods is essential to control and understand active sites’ behavior during the reaction, providing high activity and durability. This review carefully summarizes the recently reported noble metal‐based heterogeneous catalysts for thermocatalytic conversion of CO2into methane, carbon monoxide, methanol, formic acid, higher alcohols, C2+hydrocarbons, and syngas through dry reforming of CH4, to draw the state‐of‐the‐art development in the field. Finally, we critically discuss the impact of these elements on catalyst properties, the challenges related to their implementation, and future research opportunities.

Development of dual-functional materials for integrated CO2 capture and utilization by dry reforming of CH4

Integrated CO2 capture and utilization by dry reforming of CH4 (ICCU-DRM) is an effective way to achieve CO2 emission reduction and resource utilization. However, the process is still in preliminary development stage, and it lacks of efficient and stable dual-functional materials (DFMs) and full understanding of reaction characteristics of ICCU-DRM. In this work, various inert supported Ni/CaO DFMs were synthesized and evaluated by comprehensive adsorption-desorption, catalytic reaction and ICCU-DRM tests. Results show that 5Ni-5Zr/CaO/SBA possesses a very good carbon deposition resistance. Almost no carbon deposition is produced in a continuous ICCU-DRM test for 20 cycles, while the conversion of CH4 and CO2 keeps at 66% and 75%, respectively. Meanwhile, benefiting from the stable micro-structure, 10Ni-CaO-Ca5Al6O14 maintains a high CO2 conversion capacity of 0.44 g g−1 in the stability test with a CO2 and CH4 conversion of 78% and 63%.

The Capture and Catalytic Conversion of CO2 by Dendritic Mesoporous Silica‐Based Nanoparticles

Dendritic mesoporous silica nanoparticles own three‐dimensional center‐radial channels and hierarchical pores, which endows themselves with super‐high specific surface area, extremely large pore volumes, especially accessible internal spaces, and so forth. Dissimilar guest species (such as organic groups or metal nanoparticles) could be readily decorated onto the interfaces of the channels and pores, realizing the functionalization of dendritic mesoporous silica nanoparticles for targeted applications. As adsorbents and catalysts, dendritic mesoporous silica nanoparticles‐based materials have experienced nonignorable development in CO2 capture and catalytic conversion. This comprehensive review provides a critical survey on this pregnant subject, summarizing the designed construction of novel dendritic mesoporous silica nanoparticles‐based materials, the involved chemical reactions (such as CO2 methanation, dry reforming of CH4), the value‐added chemicals from CO2 (such as cyclic carbonates, 2‐oxazolidinones, quinazoline‐2,4(1H,3H)‐diones), and so on. The adsorptive and catalytic performances have been compared with traditional silica mesoporous materials (such as SBA‐15 or MCM‐41), and the corresponding reaction mechanisms have been thoroughly revealed. It is sincerely expected that the in‐depth discussion could give materials scientists certain inspiration to design brand‐new dendritic mesoporous silica nanoparticles‐based materials with superior capabilities towards CO2 capture, utilization, and storage.

Micro-kinetics analysis based on partial reaction networks to compare catalysts performances for methane dry reforming reaction

Designing a simple, yet representative reaction network for subsequent micro-kinetic analysis is important for limiting the cost of evaluation and ensuring model solvability. This is currently achieved by employing sensitivity analysis over a comprehensive reaction network (CRN) to screen reaction species. However, as a reaction network is being simplified for a particular catalyst composition, it loses its transferability to other compositions. Therefore, in this study, a two-way approach is presented to circumvent this problem. Firstly, a generalizable model outcome is identified, i.e. minimum reactant conversions (xR), based on a mass-flow analysis. Then, a stepwise workflow is developed for constructing a partial reaction network (PRN) to insure transferability of min (xR) for a range of varying catalyst energetics, in the absence of experimental data for validation. Lastly, the transferability of this approach is demonstrated for CH4 dry reforming by developing a PRN using Ni(111) as the initial catalyst and testing it over Ru(001).

Effect of ceria content in Ni–Ce–Al catalyst on catalytic performance and carbon/coke formation in dry reforming of CH4

In this study, to enhance the catalytic activity and minimize the carbon/coke formation, cerium incorporated alumina-supported new Ni–Ce–Al catalysts were investigated in dry reforming of biogas. Ni–Ce–Al catalysts were synthesized by the modified one-pot sol-gel method in an inert environment. To determine the effect of the Ce/Al ratio on physicochemical properties of catalysts and their activity, Ni (5 wt %) catalysts with different Ce/Al ratios (0/1, 1/2, 1/1, 2/1 b y wt.) were tested in a fixed-bed flow reactor using an equimolar ratio of CH4/CO2/Ar gas mixture. To explain the correlation between catalytic activity and catalyst properties, characterization studies were carried out by using N2 adsorption-desorption isotherms, XPS, XRD, SEM-EDS, TEM, ICP-OES, DRIFT, O2-TPO and TGA methods before and after activity tests. XRD analysis showed that both CeO2 and γ-Al2O3 crystalline phases with metallic Ni having different peak intensities were separately formed in all the catalysts. Among the catalysts of different Ce/Al ratios, the Ni–1Ce–1Al catalyst containing equal amounts of Al and Ce has the smallest CeO2 crystallite size. This catalyst also has the highest pore diameter and volume. XPS analysis showed that Ce incorporation into the Ni-based Al2O3 catalyst decreased the NiAl2O4 formation. DRIFT analysis indicated that the addition of ceria into the support material decreased the Lewis acidity of alumina. During 25-h long-term activity test, the conversions of CH4 and CO2 obtained with the catalyst Ni–1Ce–1Al (Ce/Al ratio is 1/1) were approximately the same and averaged 76% and 85%, respectively. This behavior of the catalyst indicates its high stability. TGA, XRD and SEM analyzes performed with the used Ni–1Ce–1Al and Ni–Al catalysts show very little carbon formation in the catalyst containing equal weights of Ce and Al compared to the catalyst without Ce. This result shows that the addition of cerium to the catalyst structure prevents carbon deposition due to its special oxygen mobility. This study showed that the crystallite size of CeO2 in the catalyst structure strongly influences preventing carbon accumulation in the dry reforming reaction.

Exploring Simultaneous Upgrading and Purification of Biomass−Gasified Gases Using Plasma Catalysis

Tar and substantial CH4 and CO2 are contained in gasified fuels, which pose an obstacle to direct chemical synthesis, and this is a predominant challenge for biomass gasification technology. Herein, a packed−bed dielectric barrier discharge (DBD) reactor was built for simultaneous CH4 dry reforming and tar removal with a La−Ni/γ−Al2O3 catalyst. The interaction between CH4 dry reforming and tar removal in plasma catalysis was investigated. The results indicated that plasma catalysis can achieve high−efficiency simultaneous tar removal and CH4 dry reforming, as indicated by the reactants’ conversion (14% increase for CCH4 and CCO2 at 450 °C in the presence of tar and a 37% increase for the tar removal rate at 360 °C when CH4 and CO2 were introduced), and the mechanism for mutual promotion of CH4 dry reforming and tar removal was elucidated through catalyst characterization results. In addition, a possible reaction mechanism for tar removal via plasma catalysis was proposed. These findings provide valuable insights for simultaneous upgrading and purification of gases generated by biomass gasification.

Two birds with one stone: MgO promoted Ni-CaO as stable and coke-resistant bifunctional materials for integrated CO2 capture and conversion

Calcium Looping coupling with CH4 dry reforming (CaLDRM) is a promising technology to achieve CO2 capture and in-situ conversion to syngas, thereby attracting much attention recently. However, the significant coke deposition and reduced activity of the Ni-CaO based bifunctional materials hinder its practical application. In this work, low-cost MgO was utilized to promote Ni-CaO bifunctional material, which successfully drives cyclic CO2 capture and conversion. On the one hand, MgO act as a stabilizer to inhibit CaO sintering, acquiring excellent CO2 capture ability and cycle stability. After 20 cycles, the 10 wt% MgO promoted Ni-CaO bifunctional materials (Ni-Ca10Mg) maintained the CO2 capture capacity of 0.53 gCO2/gmaterial, much higher than the unmodified material. On the other hand, MgO can form NiO-MgO solid solution with NiO, bringing fine Ni particle sizes and abundant oxygen species. Thanks to the effect of NiO-MgO solid solution, Ni-Ca10Mg demonstrated stable CO2 conversion and syngas yield during the isothermal CaLDRM cycles, while the coke depositions are only 0.0395 gcoke/gmaterial after 10 CaLDRM cycles, corresponding to 37.2 % of unmodified material.

Plasma-enabled catalytic dry reforming of CH4 into syngas, hydrocarbons and oxygenates: Insight into the active metals of γ-Al2O3 supported catalysts

Dry reforming of CH4 (DRM) using a plasma-enabled catalytic process is an appealing approach for reducing greenhouse gas emissions while producing fuels and chemicals. However, this is a complex process that is influenced by both catalysts and discharge plasmas, and low energy efficiency remains a challenge for this technology. Here, we developed a water-cooled dielectric barrier discharge (DBD) reactor for plasma DRM reactions over supported catalysts (Ni/γ-Al2O3, Ag/γ-Al2O3 and Pt/γ-Al2O3) prepared via plasma-modified impregnation. Results show that metal loading on γ-Al2O3 enhanced the basic nature of the catalysts and promoted the formation of discharge channels and reactive species. The maximum conversion of CO2 (21.4 %) and CH4 (27.6 %) was obtained when using Ag/γ-Al2O3. The basic nature of the catalytic materials dominated CO2 conversion, whereas the properties of the catalyst and discharge plasma determined CH4 conversion. The highest selectivity of hydrogen (∼34.5 %) and carbon-containing gas products (∼81.0 %) were attained when using the noble metal catalysts (Ag/γ-Al2O3 and Pt/γ-Al2O3), while the highest total selectivity of liquid products (14.1 %) was achieved in the presence of Ni/γ-Al2O3. Compared with γ-Al2O3, the supported catalysts demonstrated higher stability, especially for Ag/γ-Al2O3 and Pt/γ-Al2O3, which also provided higher energy efficiency for gas conversion and product formation.

Combining electrolysis with thermocatalysis for dry reforming of methane in a naturally stratifying liquid alloy-salt catalytic system

Dry reforming of methane (CH4) with carbon dioxide (CO2) is an attractive technology for producing value-added syngas and mitigating greenhouse gas emission. However, this process usually requires high energy input due to the intrinsic inertness of CH4 and CO2. Besides, the widely investigated solid Ni-based catalysts typically suffer from coking and sintering issues, leading to degradation in catalytic performance. Liquid alloys and molten salts are emerging as promising catalytic materials for CH4 dry reforming. In this work, we combine electrolysis with thermocatalysis for CH4 dry reforming in a naturally stratifying liquid alloy-salt system, which achieves effective and stable catalytic performance under relatively mild operation conditions. The conversions of CH4 and CO2 reach 37% and 95%, respectively, in a bubble column reactor comprising Ni–Bi alloy and LiNaCO3 during constant current electrolysis at 1.5 A and 900 °C. The selectivities of H2 and CO were maintained at 85% and 92%, respectively. Ab initio molecular dynamics simulation shows that the oxides of both Ni and Bi promote the C–H bond dissociation. Therefore, the electrochemical process combine electrolysis with thermocatalysis in the liquid alloy-salt system represents a promising approach to achieving effective and stable CH4 dry reforming.

The tailored role of “defect” sites on γ-alumina: A key to yield an efficient methane dry reforming catalyst with superior nickel utilization

Strong metal support interaction between Ni and γ-Al2O3, resulted from the excessive hydroxyl groups on the Al2O3 support, has restricted Ni utilization in the traditional Ni/Al2O3 catalyst, which hampered its commercial application. Meanwhile, the concept of surface defects in activating single-carbon chemicals of CH4 and CO2 has attracted much attention in heterogeneous catalysis. Thus, designing better Ni/Al2O3 system in generating surface defects without losing active Ni into Al2O3 support remains challenging. Herein, the development of tailored defect sites on Al2O3 through hydroxyl-exposed strategy shows dual role of stabilizing the active Ni sites and holding responsible for catalyzing CH4 dry reforming (DRM) reaction via a more efficient route, which emphasizes the superior behavior of the traditional Ni/Al2O3 catalyst. It is considered that it can be appropriately used for reactions using not only excellent DRM catalysts but also other Ni catalysts.

Evidence of undissociated CO2 involved in the process of C-H bond activation in dry reforming of CH4

We investigate here systematically C-H bond activation mechanism on Pt/MgO with O2, H2O and CO2, and find that dry reforming of CH4 (DRM) experiences a weak activity compared with reforming or partial oxidation of CH4. Pressure dependence shows negligible effect of CO determined within a broad CO pressure regime (<10 kPa at high-pressure CH4/CO2 (20.3 kPa) and <0.3 kPa at low-pressure CH4/CO2 (0.8 kPa)) and competitive adsorption between CH4 and CO2 (0.8 kPa), suggesting that CO2 is involved in CH4 activation as an entire molecule. Based on established Langmuir-Hinshelwood model, reaction between adsorbed CH4 and CO2 to yield formate and methyl species was kinetically relevant. Both CO2 and CH4 derivatives are the most abundant surface intermediates, being confirmed by in situ FTIR and quasi-in-situ XPS. The oxidizability of oxidant was quantitatively evaluated; CO2 has the weakest oxidizability, probably making DRM less active. DRM is structure-sensitive with terrace site of Pt as active component. The influence of reverse water–gas shift was dominant in modifying selectivity. This work will certainly reconcile contradictories on CH4 activation mechanism and push the industrial application of CH4 forward.