Dry Reforming Research Articles

LaCoO3 is a promising catalyst for the dry reforming of benzene used as a surrogate of biomass tar.

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.

Investigation of the Resistance of Metal Sintering and Coke Deposition for Structure-Evolved Char Supported Co-Based Catalysts in the Dry Reforming of Methane at Elevated Pressure

Investigation of the Resistance of Metal Sintering and Coke Deposition for Structure-Evolved Char Supported Co-Based Catalysts in the Dry Reforming of Methane at Elevated Pressure

Exploring enhanced syngas production via the catalytic performance of metal‐doped X‐Ni/CeO2 (X = Zr, La, Sr) in the dry reforming of methane

AbstractBackgroundThe quest to manufacture large amounts of syngas to bridge fossil fuels and the renewable energy ecosystem stimulates the creation of efficient and stable heterogeneous catalysts. The NiCeO2 catalysts, synthesized via ultrasonic‐assisted citric acid complexation, are highly efficient for the dry reforming of methane (DRM) reaction. Different promoter metals (Zr, La and Sr) were tested for catalytic performance and syngas production. A range of analyses, including X‐ray diffraction (XRD), N2 physisorption, H2 temperature‐programmed reduction, CO2 temperature‐programmed desorption, field emission scanning electron microscopy (FESEM), transmission electron microscopy and X‐ray photoelectron spectroscopy, were employed to characterize the physicochemical properties of the catalysts.ResultsXRD results indicated the formation of NiO, CeO2, solid solution ceria–zirconia, perovskite LaNiO3 and SrNiO3 crystalline phases. FESEM results showed the promoted catalysts (Zr, La, Sr) produce large pores to facilitate reactant diffusion, with zirconia specifically creating a spiderweb morphology. At 800 °C, the CH4 and CO2 conversions follow the sequence of NiCeO2 catalyst (CH4 = 54%, CO2 = 45%) < Sr/NiCeO2 (CH4 = 60%, CO2 = 67%) < La/NiCeO2 (CH4 = 85%, CO2 = 84%) < Zr/NiCeO2 (CH4 = 95%, CO2 = 87%). The integration of promoters in DRM catalysts has notably improved carbon formation resistance, as evidenced by the following ranking: Zr/NiCeO2 (5.1 wt%) < commercial catalyst (6.0 wt%) < La/NiCeO2 (7.85 wt%) < Sr/NiCeO2 (10.9 wt%) < NiCeO2 (11.3 wt%).ConclusionThis study demonstrates that incorporating promoters, particularly Zr, in NiCeO2 significantly enhances resistance to carbon formation. It offers valuable insights into selecting metal catalyst promoters for excellent catalytic performance in DRM. © 2024 Society of Chemical Industry (SCI).

Highly Efficient Ni@SiO2 Core–Shell Catalysts for Dry Reforming of Methane Prepared by One-Pot Microemulsion Nucleation and Coating Method

Highly Efficient Ni@SiO₂ Core–Shell Catalysts for Dry Reforming of Methane Prepared by One-Pot Microemulsion Nucleation and Coating Method

The promotion mechanisms of Mo for the dry reforming of methane reaction over a Mo-doped Ni(2 1 1) bimetallic catalyst

With the escalating severity of climate change, the DRM reaction has gained attention as an effective pathway for utilizing CO2. Enhancing reaction activity and identifying the sources of carbon deposition during the DRM reaction on Ni-based catalysts pose crucial yet challenging questions. In this study, we investigate the effects of Mo doping on the reaction activity and carbon deposition of Ni catalysts using a combined DFT and microkinetic method. In terms of the models, Mo replaced one Ni atom in the surface and subsurface layers to represent Mo in the initial stages and in prolonged on the reaction, namely NiMoU(211) and NiMoL(211). Through the analysis of electronic structure, intermediate structures, and reaction barriers compared with Ni(211), the impact of Mo doping on the surface activity and carbon deposition of Ni(211) is studied. The results indicate that the strong Ni-Mo interaction enhances intermediate stability, leading to increased reaction activity. Mo doping promotes the increase in O concentration, but at low temperatures, reaction rates decrease sharply. Furthermore, Mo doping enhances the resistance to carbon deposition on Ni(211) surfaces and improves the ability to remove carbon deposits, especially in prolonged reaction models. These findings provide new mechanistic insights into the DRM reaction on Ni(211) surfaces, which were previously well-explained by experimental results, and are valuable for understanding quantum processes.

Direct conversion of biogas to syngas over bimetallic nickel–cobalt supported on α-alumina catalysts

Syngas is an essential feedstock for many valuable chemicals, produced primarily by steam reformation of methane. Recently, dry reformation (reaction between methane and carbon dioxide) has gained importance as both the reactants are greenhouse gases (GHGs). However, dry reformation (DRM) produces syngas with a low H2/CO (<1.0). The DRM requires catalyst such as nickel supported on alumina, which results in higher coke. In this study, 6Ni–6Co/α-Al2O3 and 12Ni/α-Al2O3 catalysts were prepared by wetness impregnation. The catalysts were characterized using FESEM, XRD, XPS, BET, H2-TPR, NH3-TPD and H2-Chemisorption. The catalyst performance under DRM conditions were carried out in a fixed bed reactor at 20,000 ml/gcat.hr GHSV, between 600 °C and 700 °C, at atmospheric pressure. The performance of the catalysts was compared based on conversion of methane and carbon dioxide, hydrogen to carbon monoxide and coke deposition. The rates of consumption of methane carbon dioxide were found to be equal, and higher rates were observed for 6Ni–6Co/α-Al2O3, which is attributed to NiAl2O4/CoAl2O4 phase of active metals, higher surface area, smaller crystallite size and higher dispersion. This active phase of catalyst also responsible for higher rate of CO2 adsorption and reduced coke deposition. Highest H2/CO was found to be 1.26 for 6Ni–6Co/α-Al2O3.

High coke resistance Ni-based CH4/CO2 reforming catalysts with strong spatial confinement effect: Effect of CeO2 shell thickness

Ni-based catalysts show promise as candidates for the dry reforming of methane (DRM), yet the susceptibility to sintering and carbon deposition is a major obstacle to industrialization. This work demonstrates a mesoporous Ni-based catalyst with a thickness-tailorable CeO2 shell for enhanced spatial confinement effect for the DRM. The Ni-MCM-41@xCeO2 catalysts are prepared at various CeO2 shell thickness through a two-step hydrothermal reaction. The kinetic studies have shown that the Ni-MCM-41@2CeO2 catalyst has the lowest activation energy, producing a high conversion of CH4 and CO2 as high as around 80 % at 700 °C. Our characterizations reveal that the Ni core is tightly confined in the mesoporous skeleton of MCM-41 and within a CeO2 shell. The Ni-MCM-41@2CeO2 catalyst is able to sustain high activity for more than 10 h of operation, with a remarkably reduced carbon deposition (0.28 %) as compared with a conventional Ni-Ce/MCM-41 catalyst (8.77 %). Furthermore, the density functional theory (DFT) calculation supports that the CeO2 shell layer significantly reduces dissociation potential barrier for CH4 and CO2, hence enhancing the catalytic activity of the DRM.

Promoting surface lattice oxygen and oxygen vacancy of CeO2 for photothermal methane dry reforming over Ni/CeO2 catalysts

The ever-increasing concentrations of CH4 and CO2 result in the greenhouse effect around the world. It’s meaningful to transform the gases for environment protection. In this work, we studied photothermal methane dry reforming over Ni/CeO2 catalysts by shaping CeO2 to nanorods and nanosheets, converting the greenhouse gases to syngas and trying to resolve challenges of Ni sintering and carbon deposition in the reaction. Through characterizations of physicochemical and optical properties, the surface lattice oxygen and oxygen vacancy were verified being more promoted on the nanorods catalysts than on the nanosheets catalysts, giving the greater reforming performance. The irradiation of visible-light accelerated CH4/CO2 rates, which was originated from that the photoelectrons reduced CO2 and the holes oxidized CHx. The oxygen vacancy strengthened metal-support interaction limiting Ni sintering, and the surface lattice oxygen gasified carbon precursors decreasing carbon deposition. The synergism between thermocatalysis and photocatalysis on the optimized 5Ni/CeO2 nanorod catalyst contributed to CH4 and CO2 rates up to 204 μmol/(gcats) and 245 μmol/(gcats), respectively, at 973 K, and carbon deposition less than 0.5 wt%. These were much superior to most reported performance. The work provided a novel photothermal approach for significantly decreasing carbon deposition in methane dry reforming.

Dry reforming of model-biogas over ceria-supported nickel catalyst: the effect of charge enhanced dry impregnation on the catalytic performance and coke resistance

In this study, we investigated the effectiveness of charge charge-enhanced dry impregnation (CEDI) method on a ceria-supported nickel-based catalyst (10Ni/CeO2) used to produce synthesis (syngas) under biogas dry reforming conditions. The CEDI method was used to enhance the electrostatic adsorption of nickel precursor onto the ceria support during dry impregnation (DI), hence charge-enhanced dry impregnation. The other ceria-supported nickel-based catalyst (labelled 10Ni/CeO2-DI) was prepared by the commonly used DI method and used as the reference catalyst. The catalysts were then tested for stability and catalytic performance (biogas conversion and syngas yield) under biogas reforming conditions using CatLab-QGA equipment supplied by Hidden Analytical. The characterisation studies: X-ray diffraction (XRD), N2 adsorption/desorption, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), oxygen temperature programmed oxidation (O2-TPO), temperature programmed reduction (TPR), and H2-chemisorption were performed on the fresh and spent catalysts to gain insight into the influence of the CEDI method on dispersion, nanoparticles size of the active phase, metal-support interaction, bulk composition, and phase composition. The results showed that enhancing electrostatic attraction during the DI method produced 10Ni/CeO2-CEDI with smaller nanoparticles (3.33 nm), improved nickel dispersion from 1.40 to 5.04% and improved metal-support interaction inferred from TPR values increased from 290 to 340 °C. These favourable physicochemical properties had a positive correlation with the improvement in the conversion of model biogas feed and the least coke formation.

Mechanistic study of transition metal loaded/doped Ni − MgO catalyzed dry reforming of methane: DFT calculations

In the context of carbon peaking and carbon neutrality goals, dry reforming of methane (DRM) offers both environmental and economic benefits and holds great promise for development. In this work, based on Ni loaded MgO, two structural models constructed by transition metal loading (TM+Ni − MgO, TM=Fe, Zr, Mo) and doping (Ni − TM/MgO) were used for DRM by density functional theory (DFT). And the adsorption of CO2 and CH4 on these structures was analyzed. The partial density of states (PDOS) and charge density difference (CDD) indicate that due to the presence of unfilled electron d − orbitals in the TM atoms, electron transfer occurs between them and the p − orbitals of the C and O atoms. It facilitates the interactions and enhances the adsorption between CO2 and MgO. On this basis, the DRM reactions on Fe and Ni loaded MgO (FeNi − MgO) and Ni − loaded, Fe − doped MgO (Ni − Fe/MgO) were screened for focused research. It was revealed that the addition of Fe lowered the energy barrier values for some of the elementary reaction steps, allowing the reaction to proceed more easily. And Ni − Fe/MgO showed greater advantages by possessing more stable energy barrier fluctuation intervals (ER1 − ER3) and the smallest CO2 dissociation energy barrier.

Highly dispersed Ni nanoparticles confined in mesoporous SBA-15 for methane dry reforming with improved coke resistance and stability

Methane dry reforming (DRM) is a promising route for sustainable syngas production, in which Ni-based catalysts face challenges of metal sintering and coke formation. In this work, highly dispersed Ni nanoparticles (NPs) embedded in the mesopores of SBA-15 were prepared using a simple solid-state impregnation (SSI) method. TEM and cross-section HRTEM results clearly indicated that ultra-small Ni NPs (3–4 nm) were orderly dispersed within the mesopores of the SBA-15 support. Compared with the conventional wetness impregnation (WI) method, the Ni/SBA-15 catalyst prepared by solid-state impregnation method possessed much better catalytic activity, stability, and coke resistance in DRM. In-situ DRIFTS and semi-in-situ XRD were used to elucidate the dispersion and encapsulation mechanism of Ni within the mesopores of SBA-15 during the sample preparation process. Specifically, WI formed large NiO particles, while SSI formed smaller NiO NPs with stronger interaction between metal and support (SIMS) via forming Ni-O-Si species which is beneficial for the DRM reactivity. This work establishes relationships among catalyst preparation, structure, and DRM performance, paving the way for general template-assisted methods to prepare nanometallic catalysts for various applications.

Glycerol dry reforming over Ni supported on fibrous ZSM5 and ZY: Correlation of structural properties on H2 production

This study investigates fibrous ZSM5 (FZSM5) and Zeolite Y (FZY) as supports for producing hydrogen via glycerol dry reforming. The fibrous ZSM5 and ZY were synthesized hydrothermally with microemulsion and impregnated with 10 wt% Ni via a sonication method. The catalytic test was conducted via a vertical stainless steel fixed-bed rig, at 800°C with a glycerol/CO2 ratio of 1. XRD and N2 sorption revealed the reduced surface area and crystallinity in Ni/FZSM5 compared to Ni/FZY. Ni/FZY catalyst displayed a larger surface area (264 m2/g) and aperture width (6.70 nm) in comparison to Ni/FZSM5, which had a surface area of 238 m2/g and an aperture width of 3.90 nm. Ni/FZY also had a smaller NiO crystallite size (8.73 nm) than Ni/FZSM5 (9.79 nm), suggesting well-dispersed Ni species on the wrinkle fiber of FZY’s surface. Ni/FZY outperformed Ni/FZSM5 with 52.49 % glycerol conversion, 44.87 % H2 yield, 71.31 % CO yield, and only 14.4 % carbon formation, attributed to robust Ni-O-Si contact and larger pore diameter. The discovery highlights the catalytic efficiency of the Ni-loaded fibrous zeolite in GDR, offering versatility for application in energy storage and catalysis.

Enhancement of non-thermal plasma-catalytic CO2 reforming of CH4 using Ni/Mg–Al2O3 catalysts in a parallel plate dielectric barrier discharge reactor

CO2 and CH4 are converted to syngas by dry reforming of methane (DRM) reaction. This research investigated the effects of the Mg promoter on Al2O3-supported Ni catalysts and Mg calcination temperature on the DRM performance in a parallel plate dielectric barrier discharge reactor. The Mg promoter played a crucial role in the DRM performance, as increasing the Mg calcination temperature from 700 °C to 800 °C significantly improved the DRM performance and catalyst properties, including increased specific surface area, decreased total acidity, reduced crystallite and particle sizes, and more uniform dispersion of the Ni nanoparticles. Under these conditions, the H2 and CO selectivity were 77.0 % and 70.7 %, the CH4 and CO2 conversion were 25.1 % and 20.6 %, and the energy efficiency was 8.4 %. In addition, the catalyst was associated with a lower coking rate (0.5 mg C/gcat h), a relatively low carbon deposit of 1.5 %, and a carbon loss of 2.8 %, possibly because the weak acidity hindered the Boudouard reaction and CH4 decomposition. However, increasing the Mg calcination temperature to 900 °C increased the total acidity and Ni particle size, decreasing H2 and CO selectivities and increasing carbon deposits on the catalyst surface.

Design dual confinement Ni@S-1@SiO2 catalyst with enhanced carbon resistance for methane dry reforming

Methane dry reforming is a key method for converting greenhouse gases into valuable syngas, providing a pathway for the sustainable production of valuable compounds. Yet the challenges like particle sintering and carbon deposition have hindered the widespread application of nickel-based catalysts. This study explores innovative strategies to overcome these challenges by using zeolite supports to enhance nickel dispersity and prevent carbon deposition, as well as adopting core-shell structures to prevent metal sintering and carbon deposition. In pursuit of enhancing methane dry reforming efficacy, a Ni@S-1@SiO2 dual-shell nickel-based catalyst is designed in this study to confine exposed nickel particles on the S-1 surface within a robust mesoporous silica shell, reducing nickel particle mobility and preventing active site oxidation, thereby increasing resistance to sintering and carbon deposition. Compared to conventional single-core-shell catalysts, this design significantly reduces nickel particle mobility and active site oxidation, enhancing resistance to sintering and coking. It showed virtually no carbon deposition even after a rigorous 25-h reaction at 650 °C. In-situ DRIFTS analyses provided further insights into the underlying mechanism, confirming a Langmuir-Hinshelwood mechanism and highlighting the beneficial role of formates in preventing coke deposition. This study not only advances the understanding of core-shell catalyst structures but also paves the way for optimized nickel-based catalysts in methane dry reforming, promoting a sustainable future for syngas production.

Ni-Based Molecular Sieves Nanomaterials for Dry Methane Reforming: Role of Porous Structure and Active Sites Distribution on Hydrogen Production.

Global warming, driven by greenhouse gases like CH4 and CO2, necessitates efficient catalytic conversion to syngas. Herein, Ni containing different molecular sieve nanomaterials are investigated for dry reforming of methane (DRM). The reduced catalysts are characterized by surface area porosity, X-ray diffraction, Raman infrared spectroscopy, CO2 temperature-programmed desorption techniques, and transmission electron microscopy. The active sites over each molecular sieve remain stable under oxidizing gas CO2 during DRM. The reduced 5Ni/CBV10A catalyst, characterized by the lowest silica-alumina ratio, smallest surface area and pore volume, and narrow 8-ring connecting channels, generated the maximum number of active sites on its outer surface. In contrast, the reduced-5Ni/CBV3024E catalyst, with the highest silica-alumina ratio, more than double the surface area and pore volume, 12-ring sinusoidal porous channels, and smallest Ni crystallite, produced the highest H2 output (44%) after 300 min of operation at 700 °C, with a CH4:CO2 = 1:1, P = 1 atom, gas hour space velocity (GHSV) = 42 L gcat-1 h-1. This performance was achieved despite having 25% fewer initial active sites, suggesting that a larger fraction of these sites is stabilized within the pore channels, leading to sustained catalytic activity. Using central composite design and response surface methodology, we successfully optimized the process conditions for the 5Ni/CBV3024E catalyst. The optimized conditions yielded a desirable H2 to CO ratio of 1.00, with a H2 yield of 91.92% and a CO yield of 89.16%, indicating high efficiency in gas production. The experimental results closely aligned with the predicted values, demonstrating the effectiveness of the optimization approach.

In situ DRIFTs-based comprehensive reaction mechanism of photo-thermal synergetic catalysis for dry reforming of methane over Ru-CeO2 catalyst

Solar-driven photo-thermal dry reforming of methane (DRM) is an environmentally friendly production route for high-value-added chemicals. However, the lack of thorough understanding of the mechanism for photo-thermal reaction has limited its further development. Here, we systematically investigated the mechanism of photo-thermal DRM reaction with the representative of Ru/CeO2 catalyst. Through in situ DRIFTs and transient experiments, comprehensive investigation into the reaction steps and their reactive sites in the process of DRM reaction were conducted. Besides, the excitation and migration direction of photo-electron was determined by ISI-XPS experiments, and the change of surface defect structure induced by light was characterized by ISI-EPR experiments. Based on the above results, the photo-enhancement effect on each micro-reaction step was determined. This study provides a theoretical basis for the industrialization of photo-thermal DRM reaction and its development of catalysts.

Construction of metal-anchored and defect-rich N-doped lignite-char supported cobalt catalysts for pressurized dry reforming of methane

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 (ID/IG 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.

The methane dry reforming reaction was conducted using a combination of lamellar vermiculite molecular sieve and highly active perovskite catalyst

Dry reforming of methane (DRM) enables the conversion of two greenhouse gases, CH4 and CO2, into syngas, offering remarkable environmental and economic benefits. The primary challenge in this process lies in maintaining the catalyst's high catalytic activity and stability. In this study, natural vermiculite (VMT) was employed to modify the layer carrier with a large specific surface area and suitable pore size. By combining the structural characteristics of perovskite, we synthesized the LaNiO3/VMT-SiO2 perovskite catalyst using the citric acid complex method for methane dry reforming reaction. The results demonstrate that at T = 750 °C and GHSV = 36,000 mL/(h·gcat), the catalyst exhibits excellent activity (achieving maximum conversions of 82% for CO2 and 90% for CH4) as well as stability (up to 24 h). Characterization techniques such as XRD and TEM revealed that the catalyst possesses exceptional catalytic activity and stability due to its horizontally distributed active component Ni within perovskite. Through pretreatment, we obtained an active component Ni with small particle size and uniform dispersion along with a carrier featuring a large specific surface area. Furthermore, alkaline La2O3 in the reduced catalyst enhances its carbon resistance.

A review on solar methane reforming systems for hydrogen production

Hydrogen energy is a promising alternative to fossil fuels. Solar hydrogen production through steam and carbon dioxide methane reforming is one of the sustainable and environmentally friendly methods for supplying hydrogen. This review will focus on steam and dry methane reforming. A section on methane reforming catalysts is considered to review different types of catalysts, including noble metals, non-noble metals, and Ni-based catalysts. The catalysts section will focus on the activity and stability of the catalysts. Methane reforming using solar energy is the next main section of this review and will be discussed in detail in different types of reactors, including tubular, volumetric, and membrane reactors. Sorption-enhanced steam methane reforming using solar energy will also be discussed in detail. It should be mentioned that the highly efficient methane reforming systems will be investigated. Finally, some conclusions and future trends will be proposed in the solar methane reforming field.

Photo-Thermal Dry Reforming of Methane with PGM-Free and PGM-Based Catalysts: A Review.

Dry reforming of methane (DRM) is considered one of the most promising technologies for efficient greenhouse gas management thanks to the fact that through this reaction, it is possible to reduce CO2 and CH4 to obtain syngas, a mixture of H2 and CO, with a suitable ratio for the Fischer-Tropsch production of long-chain hydrocarbons. Two other main processes can yield H2 from CH4, i.e., Steam Reforming of Methane (SRM) and Partial Oxidation of Methane (POM), even though, not having CO2 as a reagent, they are considered less green. Recently, scientists' challenge is to overcome the many drawbacks of DRM reactions, i.e., the use of precious metal-based catalysts, the high temperatures of the process, metal particle sintering and carbon deposition on the catalysts' surfaces. To overcome these issues, one proposed solution is to implement photo-thermal dry reforming of methane in which irradiation with light is used in combination with heating to improve the efficiency of the process. In this paper, we review the work of several groups aiming to investigate the pivotal promoting role of light radiation in DRM. Focus is also placed on the catalysts' design and the progress needed for bringing DRM to an industrial scale.