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In this study, zirconia-modified alumina support (S) was used to investigate Ga-promoted Ni catalysts for dry reforming of methane (DRM). The catalysts (Ni + (0–3) wt% Ga/S) were prepared using the wet impregnation method and calcined at 700 °C for 3 h. The inclusion of Ga enhanced the surface area, basicity, and metal-support interaction of the Ni-Ga/S catalysts. Smaller Ni particles containing Ga were seen in the TEM. The most active and stable catalyst was Ni + 2.0 Ga/S, having a conversion of 35% CO2 and 28% CH4 at 600 °C and displaying less (17%) carbon deposition. Furthermore, the DRM process was optimized by a mathematical model. The model determined the optimal conditions as follows: temperature (800 °C), gas flow rate (GHSV—30,000 ml h−1gcat−1), and methane to carbon dioxide ratio (1:1). The model predicts CH4 and CO2 conversions of 76.76% and 82.0%, respectively, and an H2/CO ratio of 1.02, compared to experimental results showing CH4 conversion at 74.56%, CO2 conversion at 83.25%, and an H2/CO ratio of 1.01. The model demonstrates excellent agreement with the experimental observations, exhibiting less than 3% error. [ABSTRACT FROM AUTHOR]

Syngas, mostly hydrogen and carbon monoxide, has traditionally been produced from coal and natural gas, with biomass gasification later emerging as a renewable process. It is widely used in fuel synthesis through the Fischer–Tropsch (FT) process, where the H2/CO ratio is crucial in determining product efficiency and quality. In this sense, this study aimed to reform an emulated syngas resulting from the supercritical water gasification of biomass, tailoring it to meet the H2/CO ratio required for FT synthesis. Conditions resembling dry reforming were applied, using temperatures from 600 to 950 °C and steel wool as a catalyst. Additionally, the effects of Inconel and stainless steel as reactor materials on syngas reforming were investigated. When Inconel was used, H2/CO ratios ranged between 1.04 and 1.84 with steel wool and 1.28 and 1.67 without. When comparing reactions without steel wool performed either in the Inconel or the stainless steel reactors, those using Inconel consistently outperformed the stainless steel ones, achieving CH4 and CO2 conversions up to 95% and 76%, respectively, versus 0% and 39% with stainless steel. It was concluded that the Inconel reactor exhibited catalytic properties due to its high nickel content and specific oxides. [ABSTRACT FROM AUTHOR]

In the dry reforming of methane (DRM), the oxygen vacancies on the surface of Ni/CeO 2 catalyst play an important role in CO 2 activation, catalytic performance and coke resistance. Herein, Ni/CeO 2 catalysts doped with different amounts of La were investigated to reveal the relationship between oxygen vacancies and catalytic behavior. The addition of La leads to the reduction in size of Ni particles and stronger metal-support interaction (SMSI). Furthermore, the highest proportion of oxygen vacancies is found in 10 wt% La doped Ni/CeO 2 catalyst, which is beneficial for CO 2 activation and CH 4 dissociation. The Ni/CeLa10 catalyst shows stable methane conversion during 100 h of stability test, which is maintained at 80% without obvious decrease at 750 °C. Therefore, the catalysts with more oxygen species display outstanding activity for the DRM and assisted ability in carbon resistance. This work aims to provide a molecular understanding of the modification of DRM's inherent surface sites. • A suitable amount of La addition is crucial for the modification of CeO 2 support. • Both the oxygen vacancy and basic support are responsible for CO 2 activation. • The highly Ni dispersion and moderate SMSI decrease CH 4 activation energy over Ni/CeLa10. • The Ni/CeLa10 catalyst shows the lowest carbon deposition during the 100 h of stability test. [ABSTRACT FROM AUTHOR]

CO2 reformation of methane (CRM) and CO2 methanation are two interconnected processes with significant implications for greenhouse gas reduction and sustainable energy production for industrial purposes. While Ni-based catalysis suffers from poor stability due to coke formation or sintering, we report a super stable remedy. The active sites of mesoporous MgO were loaded using wet impregnation. The incorporation of Ni and promoters altered the physical features of the catalysts. Sm–Ni/MgO showed the smallest crystallite size, specific surface area, and pore volume. The Sm–Ni/MgO catalyst was selected as the most suitable candidate for CRM, with 82 ​% CH4 and H2/CO ratio of approximately 100 ​% and also for CO2 methanation with the conversion of carbon dioxide (82 ​%) and the selectivity toward methane reaches 100 ​% at temperatures above 300 ᵒC. Furthermore, the Sm–Ni/MgO catalyst was stable for 900 ​min of continuous reaction, without significant carbon deposition. This stability was largely due to the high oxygen mobility on the catalyst surface in the presence of Sm. Overall, we demonstrated the efficacy of using promoted Ni catalysts supported by mesoporous magnesia for the improved reformation of greenhouse gases.

Abstract Direct conversion of biogas via the integrative process of dry reforming of methane (DRM) and catalytic methane decomposition (CDM) has received a great attention as a promising green catalytic process for simultaneous production of syngas and carbon nanotubes (CNTs). In this work, the effects of reaction temperature of 700–1100 °C and CH4/CO2 ratio of biogas were investigated over NiMo/MgO catalyst in a fixed bed reactor under industrial feed condition of pure biogas. The reaction at 700 °C showed a rapid catalyst deactivation within 3 h due to the formation of amorphous carbon on catalyst surface. At higher temperature of 800–900 °C, the catalyst can perform the excellent performance for producing syngas and carbon nanotubes. Interestingly, the smallest diameter and the highest graphitization of CNTs was obtained at high temperature of 1000 °C, while elevating temperature to 1100 °C leads to agglomeration of Ni particles, resulting in a larger size of CNTs. The reaction temperature exhibits optimum at 800 °C, providing the highest CNTs yield with high graphitization, high syngas purity up to 90.04% with H2/CO ratio of 1.1, and high biogas conversion (XCH4 = 86.44%, XCO2 = 95.62%) with stable performance over 3 h. The typical composition biogas (CH4/CO2 = 1.5) is favorable for the integration process, while the CO2 rich biogas caused a larger grain size of catalyst and a formation of molybdenum oxide nanorods (MoO3). The long-term stability of NiMo/MgO catalyst at 800 °C showed a stable trend (> 20 h). The experimental findings confirm that NiMo/MgO can perform the excellent activity and high stability at the optimum condition, allowing the process to be more promising for practical applications.

Dry reforming of methane (DRM) offers a promising path for greenhouse gas conversion, but industry usually relies on pressurization conditions, and the drawback of rapid carbon deposition leading to deactivation of conventional catalysts under pressurization has hindered its industrial development. In this study, a cost-effective N-doped Co-based DRM catalyst was developed by utilizing melamine to induce heteroatom doping defects on modified lignite to overcome the problem of deactivation due to rapid carbon deposition under pressurized conditions. The catalyst, Co/CN-40 (Impregnated with 40 wt% melamine), has the smallest metal particle size (3.13 nm), the largest specific surface area (376 m2/g), high defectivity (I D /I G ratio = 0.84), enhanced metal-support interactions and a relatively high pyridine N content (48%). The evaluation of DRM activity and stability at 780 °C and 0.5 MPa demonstrates that Co/CN-40 offers the highest catalytic efficiency. The highest conversion was quickly achieved by the catalyst during activity assessments, and maintain an efficient conversion with suppressed metal agglomeration over a 100-h stability test. These improvements are attributed to the increase in the number of defects which enhances electron transfer, improves metal anchoring and boosts the adsorption and activation of reactant molecules. [Display omitted] • Increased defectivity enhances metal anchoring and inhibits metal sintering. • Co/CN-40 shows the best catalytic performance and activation rate. • Co/CN-40 under pressure effectively inhibits carbon nanotube generation. • Stable catalyst operation relies on enhanced metal anchoring. [ABSTRACT FROM AUTHOR]

Bio-oil combined steam/dry reforming (CSDR) with H2O and CO2 as reactants is an attractive route for the joint valorization of CO2 and biomass towards the sustainable production of syngas (H2 + CO). The technological development of the process requires the use of an active and stable catalyst, but also special attention should be paid to its regeneration capacity due to the unavoidable and quite rapid catalyst deactivation in the reforming of bio-oil. In this work, a commercial Rh/ZDC (zirconium-doped ceria) catalyst was tested for reaction–regeneration cycles in the bio-oil CSDR in a fluidized bed reactor, which is beneficial for attaining an isothermal operation and, moreover, minimizes catalyst deactivation by coke deposition compared to a fixed-bed reactor. The fresh, spent, and regenerated catalysts were characterized using either N2 physisorption, H2-TPR, TPO, SEM, TEM, or XRD. The Rh/ZDC catalyst is initially highly active for the syngas production (yield of 77% and H2/CO ratio of 1.2) and for valorizing CO2 (conversion of 22%) at 700 °C, with space time of 0.125 gcatalyst h (goxygenates)−1 and CO2/H2O/C ratio of 0.6/0.5/1. The catalyst activity evolves in different periods that evidence a selective deactivation of the catalyst for the reforming reactions of the different compounds, with the CH4 reforming reactions (with both steam and CO2) being more rapidly affected by catalyst deactivation than the reforming of hydrocarbons or oxygenates. After regeneration, the catalyst's textural properties are not completely restored and there is a change in the Rh–support interaction that irreversibly deactivates the catalyst for the CH4 reforming reactions (both SR and DR). As a result, the coke formed over the regenerated catalyst is different from that over the fresh catalyst, being an amorphous mass (of probably turbostractic nature) that encapsulates the catalyst and causes rapid deactivation. [ABSTRACT FROM AUTHOR]

Chemical looping dry reforming of methane (CLDRM) using perovskites as a catalyst is considered a promising option for producing hydrogen from biogas. In this work, the life-cycle performance of a system compiling a CLDRM unit paired with a water gas shift unit, a pressure swing adsorption unit, and a combined cycle scheme to provide steam and electricity was assessed. The main data needed to reflect the behavior of the reforming reaction was obtained experimentally and implemented in an Aspen Plus® simulation. Inventory data was obtained through process simulation and used to assess the environmental performance of the process in terms of carbon footprint, acidification, freshwater eutrophication, ozone depletion, photochemical ozone formation, and depletion of minerals and metals. Overall, the environmental viability of the production of green hydrogen from biogas was found to be heavily dependent on the biogas leakage in anaerobic digestion plants. The CLDRM system was benchmarked against a conventional DRM implementation for the same feedstock. While the conventional DRM plant environmentally outperformed the perovskite-based CLDRM, the latter might present advantages from an implementation point of view. [Display omitted] • Scaled-up chemical looping dry reforming of biogas for hydrogen production was simulated. • The life-cycle performance of the configuration with a perovskite catalyst was assessed. • Environmental hotspots refer to biogas leakage, natural gas processes, and catalyst metals. • Environmental advantages of conventional dry reforming were linked to heat integration. • Green hydrogen qualification requires avoiding leakages from anaerobic digestion plants. [ABSTRACT FROM AUTHOR]

Amidst the rapid expansion of the global economy, the demand for energy has escalated. The depletion of traditional energy sources coupled with environmental pollution concerns has catalyzed a shift towards the development and utilization of clean, renewable energy. Biogas, as a renewable energy source, provides diverse applications and holds the potential to alleviate energy shortages. Recently, biogas dry reforming technology has garnered substantial attention as a significant pathway for renewable energy utilization, particularly in the development and optimization of catalysts. Contemporary research predominantly focuses on enhancing the activity and stability of catalysts, with particular emphasis on their resistance to coking and sintering. This review delineates the classification of biogas dry reforming catalysts, their catalytic activity, and issues related to carbon deposition, contrasting biogas dry reforming with traditional dry reforming in catalyst design. It synthesizes numerous studies from recent years aimed at mitigating carbon deposition during the biogas dry reforming process and boosting catalytic activity via active components, carriers, and promoters in both precious and non-precious metal catalysts. Furthermore, it discusses the current challenges of biogas dry reforming technology and outlines prospective future development trends. This discussion provides an in-depth understanding of biogas dry reforming technology and catalyst design, offering insights and recommendations for future research and industrial applications. [ABSTRACT FROM AUTHOR]

Biogas conversion is a renewable alternative for producing hydrogen. In this work, dry reforming of simulated biogas was performed in a 1 kW th continuous chemical looping reforming (CLR) unit in which the oxygen required for the partial oxidation of biogas to CO and H 2 is supplied by an oxygen carrier. The performance of two different oxygen carriers (an iron oxide-based residue and a synthetic material based on an iron-manganese mixed oxide) was evaluated. The residue was capable of performing the dry reforming of biogas to a larger extent than the synthetic oxygen carrier. To enhance hydrogen yield, NiO addition was also considered with both materials. The presence of NiO increased methane conversion and H 2 selectivity for both oxygen carriers. A value of approximately 2.6 mol H 2 /mol CH 4 was achieved with both materials with the presence of only 2.7 wt% NiO in the bed. • Dry-CLR of biogas was evaluated in a 0.5 kW th chemical looping unit. • Two Fe-based oxygen carriers tested: one residue and one iron-manganese mixed oxide. • The residue performed the dry reforming of biogas in a larger extent. • NiO addition to both oxygen carriers increased methane conversion and H 2 selectivity. • Yield of 2.6 mol H 2 /molCH 4 with both materials with 2.7 wt% NiO in the bed. [ABSTRACT FROM AUTHOR]

Direct conversion of biogas via the integrative process of dry reforming of methane (DRM) and catalytic methane decomposition (CDM) has received a great attention as a promising green catalytic process for simultaneous production of syngas and carbon nanotubes (CNTs). In this work, the effects of reaction temperature of 700–1100 °C and CH4/CO2 ratio of biogas were investigated over NiMo/MgO catalyst in a fixed bed reactor under industrial feed condition of pure biogas. The reaction at 700 °C showed a rapid catalyst deactivation within 3 h due to the formation of amorphous carbon on catalyst surface. At higher temperature of 800–900 °C, the catalyst can perform the excellent performance for producing syngas and carbon nanotubes. Interestingly, the smallest diameter and the highest graphitization of CNTs was obtained at high temperature of 1000 °C, while elevating temperature to 1100 °C leads to agglomeration of Ni particles, resulting in a larger size of CNTs. The reaction temperature exhibits optimum at 800 °C, providing the highest CNTs yield with high graphitization, high syngas purity up to 90.04% with H2/CO ratio of 1.1, and high biogas conversion (XCH4 = 86.44%, XCO2 = 95.62%) with stable performance over 3 h. The typical composition biogas (CH4/CO2 = 1.5) is favorable for the integration process, while the CO2 rich biogas caused a larger grain size of catalyst and a formation of molybdenum oxide nanorods (MoO3). The long-term stability of NiMo/MgO catalyst at 800 °C showed a stable trend (> 20 h). The experimental findings confirm that NiMo/MgO can perform the excellent activity and high stability at the optimum condition, allowing the process to be more promising for practical applications. [ABSTRACT FROM AUTHOR]

Tar build-up is one of the bottlenecks of biomass gasification processes. Dry reforming of tar is an alternative solution if the oxygen chemical potential on the catalyst surface is at a sufficient level. For this purpose, an oxygen-donor perovskite, LaCoO3, was used as a catalyst for the dry reforming of tar. To circumvent the complexity of the tar and its constituents, the benzene molecule was chosen as a model compound. Dry reforming of benzene vapor on the LaCoO3 catalyst was investigated at temperatures of 600, 700, and 800 °C; at CO2/C6H6 ratios of 3, 6, and 12; and at space velocities of 14,000 and 28,000 h-1. The conventional Ni(15 wt.%)/Al2O3 catalyst was also used as a reference material to determine the relative activity of the LaCoO3 catalyst. Different characterization techniques such as X-ray diffraction, N2 adsorption-desorption, temperature-programmed reduction, and oxidation were used to determine the physicochemical characteristics of the catalysts. The findings demonstrated that the LaCoO3 catalyst has higher CO2 conversion, higher H2 and CO yields, and better stability than the Ni(15 wt.%)/γ-Al2O3 catalyst. The improvement in activity was attributed to the strong capacity of LaCoO3 for oxygen exchange. The transfer of lattice oxygen from the surface of the LaCoO3 catalyst facilitates the oxidation of carbon and other surface species and leads to higher conversion and yields. [ABSTRACT FROM AUTHOR]

To develop high-performance catalysts for greenhouse gas CO2 reforming with ethanol (EDR) is progressively inspired by the urgent requirement of CO2 elimination in order to meet with the sustainable development. In this work, the bimetallic Co(Ni)/ZnO catalyst derived from MOFs was investigated in detail with a focus on the effect of Ni dopant. The EDR results indicated that the bimetallic Co(Ni)/ZnO catalyst presented better activity as well as less formation of byproducts in comparison with the monometallic Co/ZnO catalyst. 100% of ethanol conversion was obtained at 500 °C for Co(Ni)/ZnO versus 650 °C for Co/ZnO. Moreover, no acetone formation was observed over Co(Ni)/ZnO catalyst while the concentration of acetone in Co/ZnO was as high as 10 mol%. Characterization results depicted that the strong synergistic effect between Ni and Co in Co(Ni)/ZnO catalyst might greatly stabilize active metal cobalt with smaller particle size, improve the reducibility and facilitate the generation of oxygen defects, thereby enhancing the catalytic performance. To a certain extent, this work might contribute to the design of efficient catalysts for other catalytic applications. [ABSTRACT FROM AUTHOR]

Natuna's natural gas reserve, which contains 70 %–v CO2 and 30 %–v CH4, opens a prospective method for producing syngas through the dry reforming of methane (DRM). This study used the equation and determination of kinetic parameters in a fixed-bed reactor to develop the operating conditions for the DRM process. The catalyst used was 10 %Ni/CeZrO2 and followed the Langmuir-Hinshelwood mechanism, with CH4 dissociation (activation of C–H bonds) on the Ni catalyst as the rate-determining step. According to the results, the simulation and experimental data have error values of ≤ 5 % and RMSE < 0.046. This indicates that the equation and kinetic parameters used in the simulation are valid for reactor modeling. Steady-state modeling was then conducted using a 1D quasihomogeneous model. The feed composition of CO2:CH4 = 70:30 (Natuna gas field composition) has optimized results with temperature 700 °C, CH4 conversion at 92 %, CO2 conversion at 28 %, and H2/CO ratio 1.42, and carbon formation at 7.1 mgC/gcat. This study also found that a higher CO2:CH4 feed ratio could reduce carbon formation during DRM.

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.

The current work investigated emerging fields for generating and consuming hydrogen and synthetic Fischer-Tropsch (FT) fuels, especially from detrimental greenhouse gases, CO2 and CH4. Technologies for syngas generation ranging from partial oxidation, auto-thermal, dry, photothermal and wet or steam reforming of methane were adequately reviewed alongside biomass valorisation for hydrogen generation, water electrolysis and climate challenges due to methane flaring, production, storage, transportation, challenges and opportunities in CO2 and CH4 utilisation. Under the same conditions, dry reforming produces more coke than steam reforming. However, combining the two techniques produces syngas with a high H2/CO ratio, which is suitable for producing long-chain hydrocarbons. Although the steam methane reforming (SMR) process has been industrialised, it is well known to consume significant energy. However, coke production via catalytic methane decomposition, the prime hindrance to large-scale implementation of these techniques for hydrogen production, could be addressed by coupling CO with CO2 conversion to alter the H2/CO ratio of syngas, increasing the reaction temperatures in dry reforming, or increasing the steam content fed in steam reforming. Optimised hydrogen production and generation of green fuels from CO2 and CH4 can be achieved by implementing these strategies. [ABSTRACT FROM AUTHOR]

In this study, vermiculite was explored as a support material for nickel catalysts in two key processes in syngas production: dry reforming of methane with CO2 and steam reforming of ethanol. The vermiculite underwent acid or base treatment, followed by the preparation of Ni catalysts through incipient wetness impregnation. Characterization was conducted using various techniques, including X-ray diffraction (XRD), SEM–EDS, FTIR, and temperature-programmed reduction (H2-TPR). TG-TD analyses were performed to assess the formation of carbon deposits on spent catalysts. The Ni-based catalysts were used in reaction tests without a reduction pre-treatment. Initially, raw vermiculite-supported nickel showed limited catalytic activity in the dry reforming of methane. After acid (Ni/VTA) or base (Ni/VTB) treatment, vermiculite proved to be an effective support for nickel catalysts that displayed outstanding performance, achieving high methane conversion and hydrogen yield. The acidic treatment improved the reduction of nickel species and reduced carbon deposition, outperforming the Ni over alkali treated support. The prepared catalysts were also evaluated in ethanol steam reforming under various conditions including temperature, water/ethanol ratio, and space velocity, with acid-treated catalysts confirming the best performance. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Photothermal synergistic catalysis (PTSC) offers promising potential for the dry reforming of methane (DRM) to produce syngas, but designing suitable catalysts suitable for photothermal processes poses significant challenges. In this study, we present a core-shell catalyst consisting of a SiO2 shell encapsulating Ni loaded on the CeO2–ZrO 2 support, which proved to be well-suited for PTSC-DRM under milder conditions. Compared to traditional thermal catalysis (TC), PTSC at 600 °C exhibited superior CH4/CO2 conversions (63.5 %/55.9 %) and higher H 2 /CO yields (137.0 mmol·g -1 ·h -1 /182.9 mmol·g -1 ·h -1). The TOFs under PTSC-DRM are 1.3–2.9 times higher than the corresponding TOFs in TC-DRM. The catalyst demonstrated strong stability during a 60-h aging test, which can be attributed to the restricted migration of Ni and the accelerated movement of oxygen induced by illumination via structure effect which also lead to the boosted activity benefited from a reduced bandgap of 2.2 eV and improved charge separation/migration efficiency during PTSC reaction. [Display omitted] • Boosted syngas production via photothermal synergistic dry reforming of CH 4. • A novel core-shell structured Ni/CeO 2 –ZrO 2 @SiO 2 catalyst tailored for photothermal synergistic reaction. • Enhanced activity and anti-carbon performance of the catalyst due to the encapsulation of SiO 2. [ABSTRACT FROM AUTHOR]

The complex catalyst synthesis procedure is always a hurdle in the industrialization of catalysts. Industry eagerly needs catalysts for the dry reforming of methane, which can be prepared through straightforward, cheap processes by semi-skilled workers. Herein, dual metal oxide support 10 wt% MOx (M = Ti, Si, Zr, Y) & 90 wt% Al2O3 is prepared by just mixing mechanically and thereafter, catalytic active 5 wt% Ni is dispersed over the support by impregnation method. Metal oxide pairs in ZrO2 + Al2O3, TiO2-Al2O3, SiO2 + Al2O3, and Y2O3 + Al2O3 supports are non-interacting, partially-interacting, significantly interacting (through Si–O–Al) and highly interacting (with maximum covalence character) respectively. Ni dispersed over SiO2 + Al2O3 or Y2O3 + Al2O3 supports are strongly interacted, whereas Ni/Y2O3 + Al2O3 catalyst has oxide enrichment over the surface for potential oxidation of carbon deposit. The interacting nature of metal oxide pair in support, stability of active sites and extent of oxide enrichment over the surface confirms the following order of coke deposition, Ni/Y2O3 + Al2O3 (8%) < Ni/SiO2 + Al2O3 (17%) < Ni/TiO2-Al2O3 (38.2%) < Ni/ZrO2 + Al2O3 (52.3%), as well as reverse order of catalytic activity, Ni/Y2O3 + Al2O3 (60%) > Ni/SiO2 + Al2O3 (55%) > Ni/TiO2-Al2O3 (50%) > Ni/ZrO2 + Al2O3 (47%). [ABSTRACT FROM AUTHOR]

Ni-incorporated Mg–Al type hydrotalcite-like catalytic materials were synthesized following impregnation and co-precipitation routes, and their catalytic performances were compared in the dry-reforming reaction of methane. The effects of Ru impregnation on the catalytic performance of Ni-incorporated Mg–Al were also investigated. Results showed that the catalytic performance of the Ni-incorporated Mg–Al type catalyst (NiMgAlO), which was prepared by the co-precipitation route, was highly stable during dry-reforming reaction tests performed at 600 °C, extending up to 24 h. The fractional conversion of CO2 (0.42) was higher than the fractional conversion of CH4 (0.29) due to the contribution of the reverse water gas shift reaction. However, the contribution of the reverse water gas shift reaction to the product distribution was much less with the catalyst prepared following the impregnation route (Ni@MgAlO). This difference was shown to be mainly due to the state of the nickel in the catalyst structures. Ni-impregnated Ca–Al type hydrotalcite-like catalyst (Ni@CaAlO) was also synthesized and tested in dry reforming of methane. Results obtained with the Ni-impregnated Ca–Al type catalyst showed some changes in its structure and the formation of some CaCO3 during the dry reforming reaction. The comparison of the performances of Ni-impregnated Mg–Al and Ca–Al type catalysts showed a higher amount of coke on the surface of Ni@CaAlO than Ni@MgAlO. It was also concluded that significant coke minimization and highly stable catalytic performance could be achieved by the impregnation of 1 % Ru to the NiMgAlO catalyst. The amount of coke deposited on the catalyst decreased from about 30 % to less than 5 %, by Ru impregnation. The decrease of the surface area of the Ru-impregnated catalyst was also only about 3 % after 240 min of reaction time. [ABSTRACT FROM AUTHOR]

The properties of supports (such as oxygen vacancies, oxygen species properties, etc.) significantly impact the anti-carbon ability due to their promotional effect on the activation of CO2 in dry reforming of methane (DRM). Herein, pyrochlore-type La2Ce2O7 compounds prepared using co-precipitation (CP), glycine nitrate combustion (GNC) and sol–gel (S-G) methods, which have highly thermal stability and unique oxygen mobility, are applied as supports to prepare Ni-based catalysts for DRM. The effect of the calcining temperature (500, 600 and 700 °C) on La2Ce2O7(CP) has also been investigated. Based on multi-technique characterizations, it is found that the synthesis method and calcination temperature can influence the particle size of the La2Ce2O7 support. Changes in particle size strongly modulate the pore volume, specific surface area and numbers of surface oxygen vacancies of the La2Ce2O7 support. As a result, the distribution of supported Ni components is affected due to the different metal–support interaction, thereby altering the activity of the catalysts for cracking CH4. Moreover, the supports' abilities to adsorb and activate CO2 are also adjusted accordingly, accelerating the removal of the carbon deposited on the catalysts. Finally, La2Ce2O7(CP 600) with an appropriate particle size exhibits the best catalytic activity and stability in DRM. [ABSTRACT FROM AUTHOR]

Sintering resistance and stability are pivotal objectives in the design of dry reforming of methane (DRM) catalysts. This study delves into the impact of cerium (Ce) as a promoter on the catalytic performance of Co–La bimetallic catalysts. A novel CoLa-xCe/MA catalyst was synthesized using alumina as a support via the co-impregnation method. The investigation explores the influence of Ce introduction on the catalytic performance of CoLa bimetallic catalysts and their resistance to carbon deposition. The CoLa bimetallic catalyst augments the number of oxygen vacancies on its surface during the reaction process compared to Co-based monometallic catalysts, leading to enhanced resistance to carbon deposition. Nonetheless, CoLa bimetallic catalysts are prone to active site agglomeration and sintering during the reaction, resulting in diminished catalyst stability. The introduction of Ce effectively alleviates this issue by promoting electron transfer between Ce and Co, facilitated by strong interactions between Ce and Co species. This engenders the creation of more active Co2+ sites, thereby enhancing the activation of CH 4 in the DRM reaction. XPS analysis reveals a subtle shift in the La spectrum after the introduction of Ce, indicating favorable interactions between La and Ce for enhanced catalytic performance. Moreover, the addition of Ce as a promoter significantly diminishes the presence of medium and strong basic sites on the catalyst surface, promoting the formation of more moderately basic sites conducive to the DRM reaction. This effectively enhances the catalytic capability to adsorb and activate CO 2 as well as mitigate carbon deposition during the DRM reaction process. [Display omitted] • Ce introduction enhances the catalytic performance of Co–La bimetallic catalysts. • The addition of Ce reduces strong basic sites on the catalyst surface. • Ce mitigates active site agglomeration and sintering, improving catalyst stability. • Ce promotes electron transfer between Ce and Co and improved activation of CH 4. • CoLa–5Ce/MA catalyst showed better activity and stability. [ABSTRACT FROM AUTHOR]

This paper describes the dynamic process model for a solar fuels synthesis plant currently being built in Germany. The open-source, equation-based modelling language Modelica is used as the foundation. In this plant, biogas and steam are reformed, producing synthesis gas and subsequently turned into synthetic crude oil. This work contains the necessary model setups for the thermal energy storage, solar-absorbing gas receiver and reforming reactor to consider the thermohydraulic, thermochemical and radiative interactions occurring in the process. The remaining infrastructure is modeled with the Modelica Standard Library. A way to fit these models with experimental data for validation is also outlined.

Atmospheric-pressure microwave plasma reforming of ethane (C2H6)–carbon dioxide (CO2) mixtures was investigated, potentially for plasma dry reforming of large hydrocarbons. The plasma was characterized using optical emission spectroscopy, and the reforming process was analyzed using gas chromatography and thermocouple measurements. The temperature of the plasma region reached approximately 5000 K, regardless of the specific energy input, which was sufficiently high to initiate the reforming reactions. About 90 % of the C2H6-CO2 mixture was reformed into H2 and CO with selectivities of about 83 %, at a microwave power and mixture flow rate of 2 kW and 10 slpm, respectively, while the mass flow rate of unmeasured species was less than 1 % of the total. An energy efficiency without any heat recovery schemes was determined to be 49 %, which was slightly higher than that for plasma methane dry reforming because the syngas production becomes favored at a lower temperature for ethane dry reforming. A more detailed analysis was performed by developing a reactor network model. The simulation revealed that the reforming process proceeded as the locally heated plasma flow interacts with its relatively cold surrounding flow through heat and mass transfer. Carbon monoxide (CO) was produced mainly through the reaction H + CO2 → OH + CO, whereas molecular hydrogen (H2) was mainly produced through hydrogen (H) abstraction reactions of hydrocarbons. Notably, acetylene (C2H2) and ethylene (C2H4) were the major by-products due to their higher H abstraction energies.

Syngas, mostly hydrogen and carbon monoxide, has traditionally been produced from coal and natural gas, with biomass gasification later emerging as a renewable process. It is widely used in fuel synthesis through the Fischer–Tropsch (FT) process, where the H2/CO ratio is crucial in determining product efficiency and quality. In this sense, this study aimed to reform an emulated syngas resulting from the supercritical water gasification of biomass, tailoring it to meet the H2/CO ratio required for FT synthesis. Conditions resembling dry reforming were applied, using temperatures from 600 to 950 °C and steel wool as a catalyst. Additionally, the effects of Inconel and stainless steel as reactor materials on syngas reforming were investigated. When Inconel was used, H2/CO ratios ranged between 1.04 and 1.84 with steel wool and 1.28 and 1.67 without. When comparing reactions without steel wool performed either in the Inconel or the stainless steel reactors, those using Inconel consistently outperformed the stainless steel ones, achieving CH4 and CO2 conversions up to 95% and 76%, respectively, versus 0% and 39% with stainless steel. It was concluded that the Inconel reactor exhibited catalytic properties due to its high nickel content and specific oxides.

The study aimed to explore synergies resulting from the combination of dry reforming and partial oxidation of methane, using 10%Ni/Al 2 O 3 –CeO 2 catalysts with varying CeO 2 proportions (10, 30, 50, and 70 wt%). The manufacturing involved mechanochemical and impregnation methods for supports and catalysts, respectively. The inclusion of 10 wt% CeO 2 played a crucial role in enhancing nickel dispersion and reinforcing interaction with the support. Particularly noteworthy was the exceptional performance of the 10%Ni/Al 2 O 3 –10%CeO 2 catalyst, achieving an impressive 83% methane conversion at 700 °C, surpassing other prepared nickel-based catalysts. The introduction of a small quantity of O 2 during methane dry reforming, inferred from TPO and FESEM analyses, effectively mitigated carbon deposition. Demonstrating remarkable endurance, the catalyst 10%Ni/Al 2 O 3 –10%CeO 2 maintained efficacy for 440 min at 700 °C, yielding CH 4 and CO 2 conversion rates of 93% and 34%, respectively. Higher calcination temperatures led to nickel particle aggregation, causing a decline in catalytic efficiency. • Dry reforming and partial oxidation of methane were done on Ni/Al 2 O 3 –CeO 2 catalyst. • The Ni/Al 2 O 3 –10CeO 2 possessed the best efficacy among the investigated samples. • Introducing oxygen during reforming significantly reduced carbon formation. • Higher reduction temperature boosts stability and performance. • Higher T calcination reduces BET area, lowering performance via particle sintering. [ABSTRACT FROM AUTHOR]

In order to achieve the industrial application on dry reforming of methane (DRM), it is crucial to design and develop low-cost, highly active, and stable catalysts. In this study, based on density functional theory (DFT), adsorption models of carbon atoms on four different Ni-based catalyst surfaces are constructed to investigate the process of adsorption onto O* and growth mechanism of carbon atoms Cn(n = 1–6) on different surfaces, aiming to explore the differences in carbon-resistance performance of Ni-based catalyst surfaces. It is found that carbon atom growth on flat surface occurs mainly through ring-chain combination, while on step surface, chain growth is dominant. In general, carbon is more prone to form on step surface rather than flat surface. This study reveals the growth mechanism of carbon atoms on different Ni facets at the atomic level, providing guidance for the development of high-performance Ni-based reforming catalysts. [Display omitted] • Ni(111) exhibits better carbon-resistance compared to Ni(100) of flat surface. • Ni(211) exhibits better carbon-resistance compared to Ni(311) of step surface. • Carbon is more prone to form on step surface rather than flat surface. [ABSTRACT FROM AUTHOR]

The dry reforming of methane (DRM) is a promising method for controlling greenhouse gas emissions by converting CO2 and CH4 into syngas, a mixture of CO and H2. Ni-based catalysts have been intensively investigated for their use in the DRM. However, they are limited by the formation of carbonaceous materials on their surfaces. In this review, we explore carbon-induced catalyst deactivation mechanisms and summarize the recent research progress in controlling and mitigating carbon deposition by developing coke-resistant Ni-based catalysts. This review emphasizes the significance of support, alloy, and catalyst structural strategies, and the importance of comprehending the interactions between catalyst components to achieve improved catalytic performance and stability. [ABSTRACT FROM AUTHOR]

Carbon capture and carbon reuse in the chemical plants is one of the attractive prospective approaches to decrease the concerns about global warming and climate change. In the present study, is focused on the synthesis gas production from carbon dioxide in a methanol synthesis plant. In this regard, two methanol processes are proposed based on CO 2 separation, recycling, and reforming. In the first scenario, CO 2 is separated and recycled to the conventional reformer, while the process is equipped by a CO 2 separation unit and dry methane reformer in the second scenario. The proposed processes are simulated and a sensitivity analysis is performed to investigated the effect of inputs on methanol productivity and carbon conversion. The operational parameters of proposed processes are optimized to enhance methanol productivity and CO 2 conversion. Then, the processes are compared from energy efficiency, carbon efficiency, CO 2 emission rate and methanol productivity viewpoints. The results showed that, in the second proposed scenario, methanol production rate approach to 5367 tons per day in comparison to 5030 tons per day for industrial unit. In addition, modification of conventional methanol process based on the second scenario could decrease CO 2 emission rate about 56 tons per day. [Display omitted] • Two novel methanol synthesis techniques based on CO 2 separation, recycling, and reforming were simulated. • A comparison was made between the industrial unit and two proposed configurations from the environmental and process aspect. • Various effects of operating conditions on the methanol production rate and CO 2 emissions were evaluated. • A sensitivity analysis was performed, and operational parameters were optimized to improve the proposed systems' performance. [ABSTRACT FROM AUTHOR]

The successful synthesis of the mesostructured SBA-15 derived from extracted boiler ash silica (BA) with distinct Ni loading (15 wt%, 20 wt%, and 25 wt%) towards H 2 production from CO 2 and C 3 H 8 O 3 was explored. The catalysts prepared by the ultrasonic-assisted method were subjected to 8 h of GDR at 800 °C. The XRD and N 2 sorption revealed reduced area and crystallinity in 25 wt% Ni versus 15 wt% Ni catalyst. 20 Ni/SBA-15(BA) exhibited a larger area (234 m2/g), aperture (8.99 nm), and small NiO crystallite (18.34 nm), implying well-dispersed Ni species on SBA-15(BA) surface. 20 Ni/SBA-15(BA) displayed the highest GDR catalytic activity (57 %), credited to its accessible structure, strong Ni–O–Si bonding, and good Ni dispersion that reduced coke formation (9.8 % carbon). This discovery highlights the excellent performance of 20 wt% of Ni loaded on SBA-15 by using green silica source extracted from waste material for H 2 fuel production. [Display omitted] • A novel Ni/SBA-15 catalyst for GDR synthesized from boiler ash waste. • Distinct Ni doping on SBA-15 affects the catalyst's properties and Ni–O–Si contact. • 20 Ni/SBA-15(BA) achieved 53 % H 2 and 74 % CO yields. • Small Ni particles of 20 wt % on SBA-15(BA) exhibit outstanding GDR activity. [ABSTRACT FROM AUTHOR]

A series of NiMgAl-X catalysts are prepared by adding the γ-Al 2 O 3 as a sacrificial template method through co-precipitation and applied to the dry reforming of methane (DRM). The catalysts were characterized by XRD, SEM, TEM, H 2 -TPR, CO 2 -TPD, Raman, TPH, and TG. The results show that the appropriate addition of γ-Al 2 O 3 can improve the structural stability of the catalyst so that the catalyst can maintain a well-shaped flower-like lamellar structure after calcination at 700 °C, improve the nickel dispersion and surface alkalinity to a certain extent, and improve its catalytic activity while maintaining good stability. The NMA-1 catalyst exhibits the highest catalytic activity of 73.7% and 83.2% conversion of CH 4 and CO 2 respectively after 50 h reaction, which is increased by 4.3% and 3.0% compared to the NMA catalyst. • Preparation of flower-like lamellar structure catalysts by γ-Al 2 O 3 sacrificial template method. • The introduction of γ-Al 2 O 3 enhances the structural stability of the catalyst. • The introduction of an appropriate amount of γ-Al 2 O 3 improves the catalytic activity and stability. • Increasing the temperature facilitates the catalytic activity of the catalyst. [ABSTRACT FROM AUTHOR]

The influence of MgO content on the structural characteristics and performance of bimetallic Co–Ni catalyst was investigated for CO 2 reforming of CH 4. Three different catalysts with the same amount of active metals (Co and Ni) but different Mg loading in the Mg–Al support were prepared by co-precipitation method. The catalysts were subjected to different characterization techniques to obtain information about their bulk, structural, textural properties, site formation and performance for DRM. Results showed there was reduction in the surface area (N 2 adsorption), a change from a single bulk phase spinel to dual-phase (XRD), and an increase in the degree of spinel inversion (Al-NMR) from 0.29 to 0.57, as the MgO loading changed from 25% to 65% in the support. There was also improved support basicity (CO 2 -TPD), metal support interaction changed (STEM EDX), the ease of metal reduction and site formation (Ni/Co K-edge XANES) became better as the MgO loading increased. Improved MgO loading facilitated the formation of inverse spinel and MgO - Ni/Co solid phase, which enhanced better reactants conversion and faster conversion of deposited carbon from the catalysts surface during DRM. • Composition of MgO affects the structure of Mg–Al supported Ni–Co ccatalysts. • The distribution of the active metal ions is affected by the structural variation. • The structural changes affected the spinel inversion and metal oxides reduction. • Octahedral site metal oxides were easily reduced as comapared to the tetrahedral site. • High MgO catalyst shows better metal reduction and performance for DRM. [ABSTRACT FROM AUTHOR]

The environmental performance of nonthermal plasma assisted dry reforming of methane (NTP-DRM) for hydrogen production from methane rich natural gas is investigated and compared with the current state of the art steam reforming technology through a cradle-to-gate life cycle assessment (LCA). The NTP-DRM technologies studied in this analysis include dielectric barrier, microwave, and pulsed plasma discharges. Due to the level of technology the study is considered as the prospective LCA of selected types of NTP-DRMs for hydrogen production. Of these, the NTP-DRM using microwave and pulsed plasma presented better environmental performance. The impact categories include midpoints levels applying TRACI 2.1 and AWARE for the water scarcity, using ecoinvent 3.8 and US NETL databases. The scenario analysis regarding carbon dioxide, electricity, and natural gas sources, revealed the highly dependency of NTP-DRMs technologies environmental performance to the energy efficiency of the processes. In terms of steam reforming of methane (SRM) despite the main contribution of steam use in the technology environmental performance, the uncertainty analysis showed higher sensitivity to natural gas input. Investigation showed that using renewable energy sources can have significant improvement regarding NTP-DRMs environmental performance and specifically global warming potential. Accordingly, at their current reactant conversion and product selectivity reaching the energy use of eV per molecule of reactant equal or less than 2, can be a proper target for the studied best case NTP-DRM to make their environmental behavior competitive with the state-of-the-art SRM technologies. • Prospective cradle-to-gate life cycle assessment (LCA) of selected nonthermal plasmas (NTP) for dry reforming of methane (DRM). • Comparative LCA between the NTP-DRM and the current state-of-the-art steam reforming of methane (SRM). • Uncertainty and scenario analysis, with a particular emphasis on critical hotspots. • Assessing NTP-DRM's energy efficiency requirement to make it environmentally acceptable compared to current SRM technologies. [ABSTRACT FROM AUTHOR]

Dry reforming of methane (DRM) is an environmentally friendly technology for producing syngas while consuming CO 2. However, the short lifespan of catalysts due to metal sintering, coke deposition, and sulfur poisoning hinders its widespread adoption. To address such issues, perovskite catalysts, which have shown superior performance and resistance to coke formation and poisoning, were developed. In this study, a comprehensive simulation model of a DRM reactor that employs Sr 0·92 Y 0·08 Ti 0·95 Ru 0·05 O 3-d (SYTRu5) using COMSOL Multiphysics software was developed. The objective of this study is to contribute to the understanding of the intricate dynamics of DRM process via utilizing simulation models. The simulation model considered five main reactions and calculated the properties of the gas mixture considering temperatures and compositions. Using the simulation model, the distribution of gas mole fractions and temperatures were obtained. According to the results, the H 2 yield and CO 2 conversion rate increased with increasing operating temperature. The temperature of the catalyst bed decreased rapidly owing to the endothermicity of the reaction. Additionally, the CH 4 conversion rate increased with increasing proportion of CO 2 , whereas the reaction converged to an equilibrium state and the temperature difference in the catalyst bed decreased with decreasing gas flow rate. [Display omitted] • Simulation model of dry reforming with an SYTRu5 catalyst was developed. • Experimental and simulation results showed good agreements. • CH 4 conversion rates were 58% in experiments and. 59.44% in simulation at 650 °C. • Reaction characteristics were predicted under various temperatures and gas conditions. • High H 2 yield results in decrease of temperature due to endothermic reaction. [ABSTRACT FROM AUTHOR]

Catalytic dielectric barrier discharge (DBD) plasma reactor experiments were performed in a tubular glass reactor with a 2 mm gap at 550°C to facilitate the reaction kinetics of steam added dry reforming or bireforming. The best specific energy input obtained was 11.2 eV/molecule feed at CO2:CH4:H2O of 4.5:1:4.5 ratio and gas hour space velocity (GHSV) = 432 h−1. This value was used to design a conceptual process and assess the environmental impact of methane steam reforming‐based H2 production 18.4 kmol/h CO2 emission processing into H2:CO = 2 syngas, with an emphasis on the carbon footprint. [ABSTRACT FROM AUTHOR]

A combination of a gliding arc plasmatron (GAP) reactor and a newly designed tubular catalyst bed (N-bed) was applied to investigate the post-plasma catalytic (PPC) effect for dry reforming of methane (DRM). As comparison, a traditional plasma catalyst bed (T-bed) was also utilized. The post-plasma catalytic effect of a Ni-based mixed oxide (Ni/MO) catalyst with a thermal catalytic performance of 77% CO2 and 86% CH4 conversion at 700 ℃ was studied. Although applying the T-bed had little effect on plasma based CO2 and CH4 conversion, an increase in selectivity to H2 was obtained with a maximum value of 89% at a distance of 2 cm. However, even when only α-Al2O3 packing material was used in the N-bed configuration, compared to the plasma alone and the T-bed, an increase of the CO2 and CH4 conversion from 53% and 53% to 69% and 69% to 83% was achieved. Addition of the Ni/MO catalyst further enhanced the DRM reaction, resulting in conversions of 79% for CO2 and 91% for CH4. Hence, although no insulation nor external heating was applied to the N-bed post plasma, it provides a slightly better conversion than the thermal catalytic performance with the same catalyst, while being fully electrically driven. In addition, an enhanced CO selectivity to 96% was obtained and the energy cost was reduced from ∼ 6 kJ/L (plasma alone) to 4.3 kJ/L. To our knowledge, it is the first time that a post-plasma catalytic system achieves this excellent catalytic performance for DRM without extra external heating or insulation.

A surfactant-assisted co-precipitation method was used to prepare the catalysts Co,Ni,Pd/CaO, Co,Ni,Pd/Ca0.97La3+0.03O, Co,Ni,Pd/Ca0.93La3+0.07O, and Co,Ni,Pd/Ca0.85La3+0.15O (1% each of Co, Ni, and Pd). La2O3 doping effect on the activity and stability of Co,Ni,Pd/CaO catalysts was investigated in dry reforming of methane. Catalysts were characterized by several techniques (X-ray diffraction (XRD), Brunauer–Emmett–Teller (BET), X-ray Fluorescence (XRF), Fourier Transform Infra Red (FTIR), Temperature Programmed Desorption H2 (H2-TPR), Transmission electron microscopes (TEM), and Temperature Gravimetric Analysis (TGA)) and were tested in a fixed-bed reactor at 900 °C and (Gas Hourly Specific Velocity (GHSV) = 15000 mL.gcat−1.h−1, atmospheric pressure). Adding La2O3 had little effect on the morphology of the Co,Ni,Pd/CaO catalyst. However, it played a crucial role in enhancing the catalyst’s reducibility and CO2 adsorption at high temperatures, as indicated by the activity and stability of the Co,Ni,Pd/CaO catalyst. The carbon deposition on utilized catalysts after 5 hours at 900 °C was examined using TEM and thermal gravimetric analysis (TGA) techniques. Compared to Co,Ni,Pd/CaO catalysts across the entire temperature range, the tri-metallic Co,Ni,Pd/Ca0.85La3+0.15O catalyst with a lanthanum promoter demonstrated a greater conversion of CH4 (84%) and CO2 (92 %) at a 1:1 CH4:CO2 ratio. The selectivity of H2/CO reduced in the following order: Co,Ni,Pd/Ca0.85La3+0.15O > Co,Ni,Pd/Ca0.93La3+0.07O > Co,Ni,Pd/Ca0.97La3+0.03O > Co,Ni,Pd/CaO. 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).

Glycerol dry reforming presents an intriguing approach for converting CO2, a greenhouse gas, and glycerol, a renewable resource, into syngas. This study delves into the impact of introducing 5 wt% of ZrO2, CeO2, La2O3, and Y2O3 to the Al2O3 support. Additionally, the study examines the influence of the optimal metal oxide ratio within the support formula on both structural properties and catalytic performance in the glycerol dry reforming process. To investigate these aspects, various catalyst supports were synthesized using a mechanochemical method. Subsequently, nickel-based catalysts were prepared through a wet impregnation technique. The catalysts underwent comprehensive characterization employing techniques such as XRD, BET, H2-TPR, CO2-TPD, TPO, and FESEM analyses to determine their physicochemical properties. The results demonstrated that the sample enhanced with 5 wt% ZrO2 exhibited remarkable performance metrics. Notably, it achieved a catalytic activity of 85.4% glycerol conversion at 650 ℃, while also displaying better stability and resistance to carbon deposition compared to the unpromoted catalyst throughout a 600 minutes reaction period. These enhanced attributes were attributed to the heightened specific surface area of the support (241.95 m2/gr), the effective dispersion of Ni on the support and the increase in basic sites.

Catalyst surface control is of great importance considering that a catalytic reaction initially starts with surface atoms’ interaction with reactant molecules. In the present study, we synthesized the Ni-Al2O3 dry reforming of methane (DRM) catalyst via the spray-pyrolysis-assisted evaporation-induced self-assembly (EISA) method in order to systematically investigate catalyst surface change as controlled by composition segregation. The present results showed that segregation in the Ni-Al2O3 catalyst had successfully occurred by the post-annealing process and that the segregated Ni nanoparticles were located on the catalyst surface with simultaneous reduction to metal. The size of the surface Ni nanoparticles was highly dependent on the post-annealing temperature, whereas the electronic properties did not consistently align with the trend of particle-size growth, indicating that the particle-growth mechanism underwent alterations from segregation to sintering as the temperature was increased. In other words, when the reduction temperature for metal segregation is excessively high, particle-growth on the external catalyst surface, as induced by post-annealing, is primarily attributable to particle sintering rather than to metal segregation. This phenomenon directly results in decreased Ni surface density. The catalytic DRM reaction revealed that due to sintering, the catalytic performance did not align with the trend of Ni particle-size growth, and the conversion of CH4/CO2 was closely associated with Ni surface density. This information will offer valuable insight to future research focused on development of Ni-based catalysts for DRM reactions.

Computational fluid dynamics simulations of solar-thermal dry reforming of methane using a parabolic trough configuration were performed. Parametric simulations of different combinations of gas flow rate, receiver tube emissivity, and geometric concentration ratio were conducted to determine configurations that could achieve the required catalyst temperatures of at least 700 °C to achieve high conversion of CH4 and CO2 to H2 and CO. Results showed that the concentration ratio of the parabolic trough collector had to be increased from ~70 to ~120 and the receiver-tube emissivity had to be reduced to ~0.2 to achieve bulk average catalyst temperatures of greater than 700 °C. Lower gas flow rates also reduced enthalpic heat losses and increased catalyst temperatures.

Definition: Perovskite-type oxides (ABO3) are a highly versatile class of materials. They are compositionally flexible, as their constituents can be chosen from a wide range of elements across the periodic table with a vast number of possible combinations. This flexibility enables the tuning of the materials' properties by doping the A- and/or B-sites of the base structure, facilitating the application-oriented design of materials. The ability to undergo exsolution under reductive conditions makes perovskite-type oxides particularly well-suited for catalytic applications. Exsolution is a process during which B-site elements migrate to the surface of the material where they form anchored and finely dispersed nanoparticles that are crucially important for obtaining a good catalytic performance, while the perovskite base provides a stable support. Recently, exsolution catalysts have been investigated as possible materials for CO2 utilization reactions like reverse water–gas shift reactions or methane dry reforming. [ABSTRACT FROM AUTHOR]

A surfactant-assisted co-precipitation method was used to prepare the catalysts Co,Ni,Pd/CaO, Co,Ni,Pd/Ca0.97La3+0.03O, Co,Ni,Pd/Ca0.93La3+0.07O, and Co,Ni,Pd/Ca0.85La3+0.15O (1% each of Co, Ni, and Pd). La2O3 doping effect on the activity and stability of Co,Ni,Pd/CaO catalysts was investigated in dry reforming of methane. Catalysts were characterized by several techniques (X-ray diffraction (XRD), Brunauer--Emmett--Teller (BET), X-ray Fluorescence (XRF), Fourier Transform Infra Red (FTIR), Temperature Programmed Desorption H2 (H2-TPR), Transmission electron microscopes (TEM), and Temperature Gravimetric Analysis (TGA)) and were tested in a fixed-bed reactor at 900 °C and (Gas Hourly Specific Velocity (GHSV) = 15000 mL.gcat-1.h-1, atmospheric pressure). Adding La2O3 had little effect on the morphology of the Co,Ni,Pd/CaO catalyst. However, it played a crucial role in enhancing the catalyst's reducibility and CO2 adsorption at high temperatures, as indicated by the activity and stability of the Co,Ni,Pd/CaO catalyst. The carbon deposition on utilized catalysts after 5 hours at 900 °C was examined using TEM and thermal gravimetric analysis (TGA) techniques. Compared to Co,Ni,Pd/CaO catalysts across the entire temperature range, the tri-metallic Co,Ni,Pd/Ca0.85La3+0.15O catalyst with a lanthanum promoter demonstrated a greater conversion of CH4 (84%) and CO2 (92 %) at a 1:1 CH4:CO2 ratio. The selectivity of H2/CO reduced in the following order: Co,Ni,Pd/Ca0.85La3+0.15O > Co,Ni,Pd/Ca0.93La3+0.07O > Co,Ni,Pd/Ca0.97La3+0.03O > Co,Ni,Pd/CaO. [ABSTRACT FROM AUTHOR]

3%La‐10%Co/Al2O3 catalyst was synthesized and catalytically optimized by using response surface methodology (RSM) for ethylene glycol dry reforming (EGDR). 3%La‐10%Co/Al2O3 showed excellent EGDR, whereby optimum performance (EG conversion of 80.43 %, CO2 conversion of 42.51 %, H2 yield of 76.41 %, and CO yield of 71.77 %) was attained under moderate reaction conditions (998 K, CO2 partial pressure of 15 kPa, and EG partial pressure of 23 kPa). The RSM model was statistically significant, and validation experiments showed a negligible discrepancy between the experimental and predicted values, demonstrating the validity and dependability of the model. The stability and regeneration studies evidenced the feasibility and catalytic stability of 3%La‐10%Co/Al2O3. [ABSTRACT FROM AUTHOR]

It is of great significance to design the high‐performance catalysts with good anti‐sintering and coke‐resistance properties which can efficiently convert undesirable greenhouse gas CO2 with bio‐ethanol into high value‐added syngas. To be addressed this issue, a series of SiO2‐M@CeO2 (M: Cu, Ni) catalysts with typical core@shell structure were prepared via a strong electrostatic adsorption technique. Interestingly, Ni‐based catalyst exhibited the higher activity towards ethanol dry reforming at the relatively low temperature. Meanwhile, SiO2‐Ni@CeO2 catalyst presented good stability after a 50 h tests while a serious deactivation occurred for SiO2‐Cu@CeO2 within 20 h reaction due to heavy carbon deposition and reactor blockage. Herein, the higher catalytic performance of SiO2‐Ni@CeO2 catalyst compared to SiO2‐Cu@CeO2 sample was attributed to the combination effect of its mesoporous structure, higher Ni dispersion as well as stronger Ni‐Ce interaction as depicted by BET, TEM, XPS, H2‐TPR and XRD findings. This work might provide meaningful information to other reforming processes involving coke formation and active metal sintering problems. [ABSTRACT FROM AUTHOR]