Catalytic Dry Reforming Of Methane Research Articles

Promotion Effect of H2S at High Concentrations on Catalytic Dry Reforming of Methane in Sour Natural Gas

Promotion Effect of H2S at High Concentrations on Catalytic Dry Reforming of Methane in Sour Natural Gas

Performance of NiO doped on alkaline sludge from waste photovoltaic industries for catalytic dry reforming of methane.

Alkali sludge (AS) is waste abundantly generated from solar photovoltaic (PV) solar cell industries. Since this potential basic material is still underutilized, a combination with NiO catalyst might greatly influence coke resentence, especially in high-temperature thermochemical reactions (Arora and Prasad, RSC Adv. 6:108,668-108688, 2016). This paper investigated alkaline sludge containing 3CaO-2SiO2 doped with well-known NiO to enhance the dry reforming of methane (DRM) reaction. The wet-impregnation method was used to prepare the xNiO/AS (x = 5-15%) catalysts. Subsequently, all catalysts were tested by using X-ray diffraction (XRD), nitrogen adsorption/desorption (BET), temperature-programmed reduction of hydrogen (H2-TPR), temperature-programmed desorption of carbon dioxide (TPD-CO2), field emission scanning electron microscopy (FESEM-EDX), and X-ray photoelectron spectroscopy (XPS). The spent catalysts were analyzed by thermogravimetric analysis (TGA/DTG), transmission electron microscopy (TEM), and temperature-programmed oxidation (TPO). The catalytic performance of xNiO/AS catalysts was investigated in a fixed bed reactor connected with gas chromatography thermal conductivity detector (GC-TCD) at a CH4:CO2 flow rate of 30 mL-1 during a 10-h reaction by following (Shamsuddin et al., Int. J. Energy Res. 45:15,463-15,480, 2021d). For optimization parameters, the effects of NiO concentration (5, 10, and 15%), reaction temperature (700, 750, 800, 850, and 900 °C), catalyst loading (0.1, 0.2, 0.3, 0.4, and 0.5 g), and gas hourly space velocity (GHSV) range from 3000, 6000, 9000, 12,000, and 15,000 h-1 were evaluated. The results showed that physical characteristics such as BET surface area and porosity do not significantly impact NiO percentages of dispersion, whereas chemical characteristics like reducibility are crucial for the catalysts' efficient catalytic activity. Due to the active sites on the catalyst surface being more accessible, increased NiO dispersion resulted in higher reactant conversion. The catalytic performance on various parameters that showed 15%NiO/AS exhibited high reactant conversion up to 98% and 40-60% product selectivity in 700 °C, 0.2 g catalyst loading, and 12,000 h-1 GHSV. According to spent catalyst analyses, the catalyst was stable even after the DRM reaction. Meanwhile, increased reducibility resulted in more and better active site formation on the catalyst. Synergetic effect of efficient NiO as active metal and medium basic sites from AS enhanced DRM catalytic activity and stability with low coke formation.

Kinetic Analysis of Catalytic Dry Reforming of Methane Using Ni-ZrO2/MCM-41 Catalyst

This work investigates the kinetics of catalytic dry reforming of methane (CDRM) to produce hydrogen gas using nickel-based catalysts. A new catalyst was prepared, Ni-ZrO2@MCM-41 (MCMZ) and used in the CDRM reaction. The textural, physical, and morphological scans are used to characterize the prepared catalyst. The performance of the newly prepared catalyst in terms of temperature effects and long-term stability is assessed. The reaction activation energy is studied as well. The outcomes of this study revealed that the MCMZ provided the highest conversion values for CH4 and CO2, with 89 and 91%, respectively. The optimum reaction temperature to achieve the highest syngas conversion was 800 °C. In addition, two new models that present CH4 and CO2 conversions for MCMZ as a function of reaction time to predict the rate of catalyst activity were built with very high accuracy. It was found that the activation energy was within the expected limits. Finally, the constants and reaction rate were determined. To conclude, this research creates a new catalyst with high performance to enhance hydrogen gas production from methane with carbon dioxide that contributes significantly to the field of yielding alternative energy sources.

Dry reforming of methane over Ni/Al2O3 catalysts: Support morphological effect on the coke resistance

Flower-like (Al2O3-F), wire-like (Al2O3-W) and sphere-like (Al2O3-S) alumina supported nickel catalysts (designated as Ni/Al2O3-F, Ni/Al2O3-W and Ni/Al2O3-S) were prepared for catalytic dry reforming of methane (DRM). The resultant catalysts exhibited variable catalytic activities and coke resistance performances in the reaction, which was closely dependent on their various physicochemical properties from the morphological effect of Al2O3 supports. To be precise, Ni/Al2O3-W presented adequately high catalytic activity and promising anti-coke behavior, which was attributed to its strong metal-support interaction, the surface dispersion of small-sized Ni nanoparticles and noticeable activation ability towards CO2. Ni/Al2O3-F possessed high anti-coke performance as well in terms of its significant CO2 activation ability. However, the encapsulation effect of Al2O3-F nanostructure resulted in insufficient abundance of metallic Ni active sites on the surface of Ni/Al2O3-F, thus giving rise to poor initial catalytic activity. The weak CO2 activation ability and the large particle size of metallic Ni on Ni/Al2O3-S induced the considerable formation of filamentous carbon after long-term DRM test. With regard to in situ DRIFTs analysis, the existence of OH* as the coke precursor scavenger and its reaction with the CHx* intermediate species from CH4 cracking were demonstrated to play crucial roles in dominating the overall anti-coke performances of Ni/Al2O3 catalysts. This work provides new insights into the development of high coke-resistance Ni-based catalysts from the perspective of support morphology modulation.

Low-Temperature Plasma-Assisted Catalytic Dry Reforming of Methane over CeO2 Nanorod-Supported NiO Catalysts in a Dielectric Barrier Discharge Reactor.

Nonthermal plasma (NTP)-assisted catalytic dry reforming of methane (DRM) is considered a powerful single-stage reaction mechanism because of its ability to activate normally stable CO2 and CH4 at a low temperature under ambient conditions. The thermodynamic barrier of DRM requires a high operating temperature (>700 °C), which can be reduced by nonequilibrium plasma. Herein, we present a method for the wet-impregnation synthesis of CeO2 nanorod (NR)-supported 5 and 15 wt % NiO catalysts for efficient NTP-promoted DRM with an applied power in the range of 24.9-25.8 W (frequency: 20 kHz), a CH4:CO2 feed gas ratio of 100:250 sccm, and a total flow rate of 350 sccm. The presence of NTP dramatically increased the reaction activity, even at 150 °C, which is usually inaccessible for thermally catalyzed DRM. The CH4 and CO2 conversion reaches a maximum of 66 and 48%, respectively, at 500 °C with the 15 wt % NiO/CeO2 NR catalyst, which are much higher than the values obtained for the 5 wt % NiO/CeO2 NR catalyst under the same conditions. According to the X-ray photoelectron spectroscopy profile for 15 wt % NiO/CeO2 NR, a higher concentration of NiO on CeO2 increases the proportion of Ce3+ in the catalyst, suggesting enhanced oxygen vacancy concentration with an increased amount of NiO loading. Additionally, a higher NiO loading promotes a higher rate of replacement of Ce4+ with Ni2+, which generates more oxygen vacancies due to the induced charge imbalance and lattice distortion within the CeO2 lattice. As a result, it can be inferred that the incorporation of Ni ions into the CeO2 structure resulted in inhibited growth of CeO2 crystals due to the creation of a NixCe1-xO2-α solid solution and the production of oxygen vacancies.

Coke resistant NiCo/CeO2 catalysts for dry reforming of methane derived from core@shell Ni@Co nanoparticles

Core@shell Ni@Co and bimetallic alloyed Ni–Co nanoparticles with controlled Co/Ni compositions were prepared and supported on CeO2 to investigate their performance in catalytic dry reforming of methane (DRM) and occurrence of sintering and coking. Increasing the Co/Ni ratio significantly reduced coke deposition while maintaining catalytic activity for DRM. However, a Co/Ni ratio > 1 caused a rapid decrease in activity. The Ni@Co1/CeO2 catalyst exhibited the highest CH4 and CO2 conversions, with long-term stability during DRM at 800 °C for 100 h. The initial core@shell structure of the Ni@Co1/CeO2 catalyst transformed to a homogeneous alloy after DRM at 800 °C for 10 h, losing its Co shell. However, the bimetallic alloyed Ni–Co1/CeO2 catalyst transformed into a non-uniform alloy rich in Co on the surface after DRM for 10 h. As the elemental distribution of the NPs becomes more homogeneous, Ni–Co1/CeO2 exhibit similar catalytic activity to Ni@Co1/CeO2 after 50 h. The oxygen vacancies on the CeO2 surface provided oxygen atoms to the Ni surface, removing carbon species deposited and releasing CO. Therefore, Ni@Co1/CeO2 catalyst provides excellent catalytic activity and stability due to the rapid formation of a homogenous alloy and the synergistic effect of Co and CeO2.

Photoinducing Different Mechanisms on a Co-Ni Bimetallic Alloy in Catalytic Dry Reforming of Methane

Photoinducing Different Mechanisms on a Co-Ni Bimetallic Alloy in Catalytic Dry Reforming of Methane

A DFT study on the role of oxygen vacancy on m-ZrO2 ([formula omitted]) in adsorption and dissociation of CO2

The performance stability of a Catalytic Dry Reforming of Methane (CDRM) catalyst is primarily determined by its ability to resist coke formation. This is possible through removal of carbon deposited on the hydrogen production sites of the catalyst by mobile surface oxygen formed via CO2 dissociation. In this study, it is aimed to understand the role of oxygen vacancies in activation and dissociation of CO2 molecule on m-ZrO2, which has been widely studied as the support of CDRM catalysts. For this purpose, first, oxygen vacancy formation on m-ZrO2 (1¯11) surface was investigated. Two possible types of oxygen vacancies were determined based on the results of periodic DFT calculations. Then, CO2 adsorption onto both stoichiometric and nonstoichiometric m-ZrO2 (1¯11) surfaces were performed. The results revealed that the CO2 dissociation is possible only on the nonstoichiometric m-ZrO2 surfaces, and that presence of an oxygen vacancy, regardless of its type, significantly lowers the adsorption energy and increases adsorbate–metal oxide interaction. The study presented here theoretically proves at atomic scale that oxygen vacancies have a great influence on the dissociative CO2 adsorption ability of m-ZrO2, and confirms its clear potential as a support to be used in technical CDRM catalysts prepared for practical applications.

Non-thermal plasma catalytic dry reforming of methane over Ni-Co3O4 supported modified-titania catalysts: Effect of process conditions on syngas production

The dry reforming of methane has been studied over modified TiO2-supported 10%Ni-5%Co3O4 composite catalysts using a non-thermal plasma dielectric barrier discharge fixed-bed reactor. The 10%Ni-5%Co3O4/modified-TiO2 nanorods (NR) have been synthesized by hydrothermal method. Physicochemical characterizations of the composite catalysts have been conducted by X-ray diffraction (XRD), H2 temperature-programmed reduction (H2-TPR), CO2 temperature-programmed desorption (CO2-TPD), high-resolution transmission electron microscopy (HRTEM) and N2 adsorption-desorption (BET) analysis. Incorporation of cubic-structured Co3O4 into Ni/TiO2 attributes to the enhancement of basicity, reducibility and metal-support interaction. Consequently, the catalytic activity of 10%Ni-5%Co3O4/TiO2 NR increases and confer CH4 and CO2 conversions at 86.4% and 84.9%, respectively. Meanwhile, the H2 and CO selectivity are reported as 50.1% and 49.0% respectively. Higher syngas ratio (H2/CO) from 0.84 to 1.01 and 26% increment in overall energy efficiency compared to plasma DRM alone have been observed. The superior plasma DRM performance is correlated to the greater basicity properties and the synergistic effect of non-thermal plasma with the 10%Ni-5%Co3O4/modified-TiO2 catalyst composite.

Extraordinary Catalytic Performance of Nickel Half‐Metal Clusters for Light‐Driven Dry Reforming of Methane

AbstractGlobal warming and the energy shortage due to the burning of fossil fuels are two major challenges. A strategy of light‐driven catalytic dry reforming of methane (DRM) using inexhaustible solar energy has provided an effective approach to tackle these challenges. Loaded metallic Ni nanoparticles have been identified as promising catalysts as alternatives to noble metals for DRM. However, they suffer from quick deactivation caused by severe coking due to thermodynamically inevitable side‐reactions. Herein, a unique nickel half‐metal catalyst of monolayer nickel clusters stabilized by alumina is reported, with 100% atomic utilization efficiency and extraordinary catalytic performance for light‐driven DRM, dramatically different from its counterpart of conventional metallic Ni nanoparticles. It has extremely high specific H2 and CO production rates of 8572.96 and 9614.26 mmol min−1 gNi−1, more than one order of magnitude higher than those of Ni nanoparticles. No detectable coke is formed due to the alteration of kinetic processes for DRM, resulting in the inhibition of coke deposition. It is discovered that light not only significantly enhances catalytic activity, but also enables quick thermocatalytic deactivation to be durable due to the oxidation of carbon species and the desorption of strongly adsorbed CO2 and CO being dramatically promoted by light.

A review on catalyst development for conventional thermal dry reforming of methane at low temperature

AbstractCarbon dioxide (CO2) utilization and conversion, as one of the main parts of carbon capture, utilization, and storage (CCUS), is not only considered an important way to mitigate global warming but also an attractive industrial route to produce valuable fuels and chemical feedstocks. Catalytic dry reforming of methane (DRM) is a promising technology for carbon dioxide utilization and conversion as it can produce syngas, carbon monoxide (CO), and hydrogen (H2) for widespread industrial production processes. In most studies of the DRM reaction, a relatively high operational temperature (i.e., >700°C) has been applied since the reactivity limitation of widely used Ni‐based catalysts at low temperatures and the extremely endothermic property of the DRM reaction. However, high cost and high requirement of thermal stability for catalysts have become a severe problem impeding the further commercialization of DRM technology. Decreasing the operational temperature (i.e., <700°C) is considered a promising way for further application of the DRM route to convert CO2 and produce syngas. However, traditional Ni‐based catalysts suffered from unsatisfied reactivity and severe coke formation, leading to quick deactivation at low temperatures. Developing a catalyst with excellent catalytic activity, coke resistance, and improved thermal stability is necessary for low‐temperature DRM reactions. In recent years, with significant development in materials, catalyst design, and computational simulation, some synthesized catalysts have achieved considerable improvement in catalytic performance in low‐temperature DRM. Hence, a review of recent development on low‐temperature DRM catalysts is provided here to further guide and profoundly understand catalyst design for low‐temperature DRM.

The Nature of Active Sites for Plasmon‐Mediated Photothermal Catalysis and Heat‐Coupled Photocatalysis in Dry Reforming of Methane

Solar energy‐induced catalysis has been attracting intensive interests and its quantum efficiencies in plasmon‐mediated photothermal catalysis (P‐photothermal catalysis) and external heat‐coupled photocatalysis (E‐photothermal catalysis) are ultimately determined by the catalyst structure for photo‐induced energetic hot carriers. Herein, different catalysts of supported (TiO2‐P25 and Al2O3) platinum quantum dots are employed in photo, thermal, and photothermal catalytic dry reforming of methane. Integrated experimental and computational results unveil different active sites (hot zones) on the two catalysts for photo, thermal, and photothermal catalysis. The hot zones of P‐photothermal catalysis are identified to be the metal–support interface on Pt/P25 and the Pt surface on Pt/Al2O3, respectively. However, a change of the active site to the Pt surface on Pt/P25 is for the first time observed in E‐photothermal catalysis (external heating temperature of 700 °C). The hot zones contribute to the significant enhancements in photothermal catalytic reactivity against thermocatalysis. This study helps to understand the reaction mechanism of photothermal catalysis to exploit efficient catalysts for solar energy utilization and fossil fuels upgrading.

Highly dispersed Ni nanoparticles supported by porous Al2O3rods for catalytic dry reforming of methane

Highly dispersed Ni–Al2O3catalysts showed long-term stability for catalytic dry reforming of methane.

Lanthanum-Promoted Nickel-Based Catalysts for the Dry Reforming of Methane at Low Temperatures

In recent decades, considerable attention has been paid to the catalytic dry reforming of methane to obtain syngas. This reaction has very important environmental implications due to the utilization of CH4 and CO2, gases that contribute to the greenhouse effect. The dry reforming of methane is normally carried out over strong basic catalysts with noble metals. Nickel has emerged as an interesting alternative, although it tends to deactivate and form carbon whiskers, which could block the reactor. It is therefore necessary to improve their catalytic performance (conversion, selectivity and stability). In this work, Ni0.69La0.31 and Ni0.14Mg0.55La0.31 were studied in the dry methane reforming reaction. The precursors were prepared by co-precipitation and the oxide phases were obtained by calcining these precursors at 450°C/6 h. The XRD diagrams of the calcined samples show the formation of mixed oxide phases with a periclase-like structure. Analysis of the temperature-programmed reduction shows that the presence of Mg shifts the reduction to higher temperatures. The catalysts, reduced at 650°C, were tested in this reaction as a function of operating time at 650°C. No deactivation occurred after 20 h of operation. Furthermore, the combination of Mg and La drastically improves the conversion and selectivity of the catalyst (> 95%).

Optical and experimental evaluation of a directly irradiated solar reactor for the catalytic dry reforming of methane

Dry reforming of methane is a process to produce syngas which is a major precursor for many chemicals and ultra-clean fuels. It is a CO2-assisted process that leads to the conversion of CO2 to higher-value products but is also a highly endothermic process that requires significant amounts of energy in the form of CO2 emitting fuels. For these reasons, this study focused on the direct utilization of concentrated solar energy by irradiating the catalyst directly rather than via a heat transfer fluid or conductive heat transfer. In addition, it uniquely adopts a tubular reactor with transparent (quartz) walls configuration, which allows extending the length of the irradiated (hot) zone to control the residence time. The new reactor was designed using Monte-Carlo ray-tracing modeling and evaluated experimentally using a commercial Ni-based catalyst. In brief, the reacting gas mixture (CH4:CO2 − 5 %: 5 %) was fed into the reactor at weight gas hourly space velocities of around 17–58 l h−1g−1 and three different temperature levels (550 °C, 650 °C, and 800 °C). Although the non-conventional mode of heating, the achieved methane conversions (∼93 % at 800 °C to ∼ 53 % at 550 °C) and H2 / CO ratios (∼0.9 at 800 °C to ∼ 0.4 at 550 °C) were similar to literature studies with the same catalyst. At the same time, the quartz walls showed no degradation after more than 80 h of intermittent testing. On the other hand, the overall energy efficiency was estimated to be less than 1 %, considering the radiation intercepted by the reactor system. However, it rose to 5 % − 25 % when correcting for the actual amount of irradiance on the catalytic bed.

Development of Ni-Co supported on SBA-15 catalysts for non-thermal plasma assisted co-conversion of CO2 and CH4: Results and lessons learnt

This study presents an investigation of using Co doping strategy to improve the Ni on mesoporous SBA-15 catalyst for promoting catalytic dry reforming of methane (DRM) under non-thermal plasma (NTP) conditions. The work was conducted by following the conventional procedures including pre-/post-reaction characterisation of the relevant catalysts, comparative assessment of various scenarios under the NTP condition and longevity tests. However, we found that the performance enhancement of the NTP system was mainly due to the use of the catalytically inert SBA-15 packing, rather than the variation of metal species on it though the results suggest the possible surface reactions on the metal surfaces. Hence, under the NTP condition, the so-called DRM might be mistaken because (i) the production of H2 and CO was likely due to the electron-impact dissociation of CO2/CH4 in gas discharge and (ii) surface reactions on a DRM catalyst are rather insignificant. We then carefully analysed and reflected on the findings and proposed further research questions to be shared with the colleagues in the field of NTP catalysis.

Structure‐Property Relations of Nickel and Cobalt Substituted Yttrium Aluminum Garnets as Catalyst Materials for Dry Reforming of Methane

AbstractNickel‐ and cobalt‐substituted yttrium aluminum garnets (YAGs) were synthesized varying their stoichiometries and the details of the thermal treatment procedures at elevated temperatures. Ni and/or Co substitution into the framework of Y3Al5O12 was found to be feasible up to molar metal contents of 6 mol %. The synthesis conditions were optimized towards a compromise of high phase purity of the high‐temperature phase of YAG, still maintaining sensible specific surface areas of the resulting catalyst materials. The two synthetic procedures evaluated in the study allow introduction of nickel and cobalt into the oxidic framework of the YAG oxide, from which under reducing conditions, both metals can be exsolved. The catalysts were studied in the catalytic dry reforming of methane under stoichiometric ratio of CO2/CH4 at atmospheric pressure. The catalytic results indicate that for the best candidate materials performance is stable and a syngas of the desired ratio nH2/nCO = 1 is formed. Trends were observed towards nickel being the catalytically more active metal compared to cobalt.

Microwave vs conventional heating in hydrogen production via catalytic dry reforming of methane

The world's energy systems are undergoing radical change driven by the commitments to achieve net zero emissions and energy independence. Development of clean hydrogen economy is of paramount importance and hydrogen is expected to play a more important role in the future energy market. An interesting way to produce hydrogen is via dry reforming reaction which uses two green house gasses (CH4 and CO2) as feedstock. Dry reforming is a challenging reaction to scale-up due to its high endothermic and coke formation nature. Microwave has gained interest in the past years as a superior heating mechanism in catalytic reactions due to its capacity in enhancing conversions of reactants and selectivity of products, and suppression of coke formation. Such characteristics has made microwave an excellent alternative to conventional heating in dry reforming reaction. In this study, we aim to discuss different aspects of microwave heating technology and its application in the catalytic dry reforming of methane. The advantages of microwave-assisted methane reforming are discussed via the comparison to the conventional heating.

Modification Strategies of Ni-Based Catalysts with Metal Oxides for Dry Reforming of Methane

Syngas generated from the catalytic dry reforming of methane (DRM) enables the downstream production of H2 fuel and value-added chemicals. Ni-based catalysts with metal oxides, as both supports and promoters, are widely applied in the DRM reaction. In this review, four types of metal oxides with support confinement effect, metal-support interaction, oxygen defects, and surface acidity/basicity are introduced based on their impacts on the activity, selectivity, and stability of the Ni-based catalyst. Moreover, the structure–performance relationships are discussed in-depth. Finally, conclusive remarks and prospects are proposed.

Quo Vadis Dry Reforming of Methane?—A Review on Its Chemical, Environmental, and Industrial Prospects

In recent years, the catalytic dry reforming of methane (DRM) has increasingly come into academic focus. The interesting aspect of this reaction is seemingly the conversion of CO2 and methane, two greenhouse gases, into a valuable synthesis gas (syngas) mixture with an otherwise unachievable but industrially relevant H2/CO ratio of one. In a possible scenario, the chemical conversion of CO2 and CH4 to syngas could be used in consecutive reactions to produce synthetic fuels, with combustion to harness the stored energy. Although the educts of DRM suggest a superior impact of this reaction to mitigate global warming, its potential as a chemical energy converter and greenhouse gas absorber has still to be elucidated. In this review article, we will provide insights into the industrial maturity of this reaction and critically discuss its applicability as a cornerstone in the energy transition. We derive these insights from assessing the current state of research and knowledge on DRM. We conclude that the entire industrial process of syngas production from two greenhouse gases, including heating with current technologies, releases at least 1.23 moles of CO2 per mol of CO2 converted in the catalytic reaction. Furthermore, we show that synthetic fuels derived from this reaction exhibit a negative carbon dioxide capturing efficiency which is similar to burning methane directly in the air. We also outline potential applications and introduce prospective technologies toward a net-zero CO2 strategy based on DRM.