scholarly journals Ni-Silica-based Catalysts for CH4 Reforming by CO2 with Enhanced Stability: Recent Designs and the Impacts of Ni Confinement, Promoters, and Core-Shell Structures

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Oscar Daoura ◽  
◽  
Maya Boutros ◽  
Franck Launay ◽  
Keyword(s):  
Heterogeneous Catalysts ◽  
Catalyst Deactivation ◽  
High Surface ◽  
High Surface Area ◽  
Dry Reforming ◽  
Dry Reforming Of Methane ◽  
Future Research ◽  
Co2 Reforming ◽  
Co2 Reforming Of Ch4 ◽  
Oxide Support

CO2 reforming of CH4, also referred to as the Dry Reforming of Methane (DRM), is considered an excellent method to produce H2 and CO (syngas), which are known to be used for the production of higher alkanes and oxygenates. Despite nickel’s moderate toxicity, Ni-based heterogeneous catalysts are considered excellent candidates for use in DRM due to their reasonable performances and economic advantages. However, these materials also present severe drawbacks, such as sintering of the active phase and coke (carbon) deposition, which may, in certain cases, lead to severe catalyst deactivation. Several synthesis strategies, mostly based on the stabilization of nickel through oxide support, have been developed to overcome these issues. Silica-based materials are investigated widely due to their availability, high surface area, and the confinement capacity conferred by their controlled porosity. The present review summarizes the progress in the design of Ni/silica-based catalysts for the dry reforming of methane between the years 2015 and 2018. The different strategies implemented are discussed to assist future research works in designing the anti-coking and anti-sintering nickel-silica-based catalysts.

scholarly journals Dry Reforming of Methane over NiLa-Based Catalysts: Influence of Synthesis Method and Ba Addition on Catalytic Properties and Stability

Catalysts ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 313 ◽  
Author(s):  
Ruan Gomes ◽  
Denilson Costa ◽  
Roberto Junior ◽  
Milena Santos ◽  
Cristiane Rodella ◽  
...  
Keyword(s):  
Catalyst Deactivation ◽  
Synthesis Method ◽  
Dry Reforming ◽  
Dry Reforming Of Methane ◽  
Co2 Reforming ◽  
Catalyst Structure ◽  
Wet Impregnation ◽  
Co2 Reforming Of Ch4 ◽  
Key Factor

CO2 reforming of CH4 to produce CO and H2 is a traditional challenge in catalysis. This area is still very active because of the potentials offered by the combined utilization of two green-house gases. The development of active, stable, and economical catalysts remains a key factor for the exploitation of natural gas (NG) with captured CO2 and biogas to produce chemicals or fuels via syngas. The major issue associated with the dry reforming process is catalyst deactivation by carbon deposition. The development of suitable catalyst formulations is one strategy for the mitigation of coking which becomes especially demanding when noble metal-free catalysts are targeted. In this work NiLa-based catalyst obtained from perovskite precursors La1−xBaxNiO3 (x = 0.0; 0.05; 0.1 and 0.2) and NiO/La2O3 were synthesized, characterized by in situ and operando XRD and tested in the dry reforming of methane. The characterization results showed that the addition of barium promoted BaCO3 segregation and changes in the catalyst structure. This partly affected the activity; however, the incorporation of Ba improved the catalyst resistance to deactivation process. The Ba-containing and Ba-free NiLa-based catalysts performed significantly better than NiO/La2O3 catalysts obtained by wet impregnation.

scholarly journals Effects of the Mg addition on characteristics and catalytic activity of Ni/-Al2O3 in dry reforming of methane

2018 ◽  
Vol 1 (T5) ◽  
pp. 85-94
Author(s):  
Loc Cam Luu ◽  
Tri Nguyen ◽  
Cuong Tien Hoang ◽  
Tien Trong Nguyen ◽  
Minh Hoang Phan ◽  
...  
Keyword(s):  
Reaction Temperature ◽  
Flow Reactor ◽  
Coke Formation ◽  
Dry Reforming ◽  
Dry Reforming Of Methane ◽  
Co2 Reforming ◽  
Temperature Programmed Oxidation ◽  
Co2 Reforming Of Ch4 ◽  
Temperature Programmed ◽  
Α Al2o3

Effectively using CO2-containing natural gas is an urgent requirement in Vietnam. Therefore, producing hydrogen and syngas by dry reforming of methane (СН4+СО2 = 2Н2+2СО) has gained renewed interest in recent years. In this paper, Ni/α- Al2O3 and Ni-Mg/α-Al2O3 catalysts were prepared by impregnation. Physico-chemical characteristics of catalysts were investigated via nitrogen physisorption (BET), X-Ray Diffraction (XRD), Transmission Electron Microscopy (TEM), and Temperature Programmed Reduction (TPR) methods. The activities of catalysts in CO2 reforming of CH4 were studied in a micro-flow reactor in the temperature range 550 –800oC, and content of CH4 and CO2 of 3 % mol. It was found that the conversion of CH4 and CO2 remarkably increased with the increase of reaction temperature from 550 to 700oC, but increased inconsiderably when the temperature reached more than 700oC. The selectivities of CO and H2 reached over 91 %. The modification of Ni/α- Al2O3 catalyst with Mg led to reduce the NiO particle size forme the new ZnO-MgO solid solution and increase the reductivity of catalyst. These improve the activity, selectivity and stability of catalyst. At the reaction temperature of 700oC, the conversions of CH4 and CO2 on Ni-Mg/α-Al2O3 reached 88.5 % and 72.3 %, respectively. The activities of catalysts were stable for 30 hours of reaction. Moreover, the role of Mg in the resistance to the coke formation on the catalyst surface was clarified via the results of temperature programmed oxidation (TPO) of spent catalysts after running the reaction for 30 hours at 700oC

scholarly journals Fabrication of Ni-Based Bimodal Porous Catalyst for Dry Reforming of Methane

Catalysts ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1220
Author(s):  
Linghui Lyu ◽  
Yunxing Han ◽  
Qingxiang Ma ◽  
Shengene Makpal ◽  
Jian Sun ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Noble Metals ◽  
Carbon Deposition ◽  
Physical Adsorption ◽  
High Surface ◽  
High Surface Area ◽  
Dry Reforming ◽  
Dry Reforming Of Methane ◽  
Porous Catalyst ◽  
Temperature Programmed

Dry reforming of methane (DRM) can effectively convert two greenhouse gases into high-valued chemicals, in which the syngas produced by the reaction can be directly used as raw gases for Fischer–Tropsch synthesis and methanol synthesis. Ni-based catalysts for the DRM reaction with comparable initial activity to noble metals are the focus of most researchers, but their poor carbon deposition resistance easily causes their low stability. More importantly, the nickel loading will affect the catalytic activity and carbon deposition resistance of the catalyst. Herein, a series of Ni/Al2O3 catalysts with bimodal pores was prepared and characterized by X-ray diffraction (XRD), N2 physical adsorption–desorption, H2-temperature programmed reduction (H2-TPR), temperature programmed hydrogenation (TPH), Raman, and thermogravimetric analysis (TG). The results show that the interesting bimodal structure catalysts could provide a high surface area and contribute to the mass transfer. Besides, the catalytic performance of the DRM reaction is sensitive to nickel loadings. In this study, the Ni/Al2O3 catalyst with nickel loadings of 6% and 8% exhibited excellent catalytic activity and carbon deposition resistance. These findings will provide a new strategy to design a highly efficient and stable heterogeneous catalyst for industry.

scholarly journals Hydrogen Yield from CO2 Reforming of Methane: Impact of La2O3 Doping on Supported Ni Catalysts

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2412
Author(s):  
Ahmed Abasaeed ◽  
Samsudeen Kasim ◽  
Wasim Khan ◽  
Mahmud Sofiu ◽  
Ahmed Ibrahim ◽  
...  
Keyword(s):  
Coke Formation ◽  
Dry Reforming ◽  
Dry Reforming Of Methane ◽  
Hydrogen Yield ◽  
Co2 Reforming ◽  
Base Catalysts ◽  
Surface Areas ◽  
Oxide Support ◽  
Surface Basicity

Development of a transition metal based catalyst aiming at concomitant high activity and stability attributed to distinguished catalytic characteristics is considered as the bottleneck for dry reforming of methane (DRM). This work highlights the role of modifying zirconia (ZrO2) and alumina (Al2O3) supported nickel based catalysts using lanthanum oxide (La2O3) varying from 0 to 20 wt% during dry reforming of methane. The mesoporous catalysts with improved BET surface areas, improved dispersion, relatively lower reduction temperatures and enhanced surface basicity are identified after La2O3 doping. These factors have influenced the catalytic activity and higher hydrogen yields are found for La2O3 modified catalysts as compared to base catalysts (5 wt% Ni-ZrO2 and 5 wt% Ni-Al2O3). Post-reaction characterizations such as TGA have showed less coke formation over La2O3 modified samples. Raman spectra indicates decreased graphitization for La2O3 catalysts. The 5Ni-10La2O3-ZrO2 catalyst produced 80% hydrogen yields, 25% more than that of 5Ni-ZrO2. 5Ni-15La2O3-Al2O3 gave 84% hydrogen yields, 8% higher than that of 5Ni-Al2O3. Higher CO2 activity improved the surface carbon oxidation rate. From the study, the extent of La2O3 loading is dependent on the type of oxide support.

Electron holography of catalysts

1995 ◽  
Vol 53 ◽  
pp. 416-417
Author(s):  
A. K. Datye ◽  
D. S. Kalakkad ◽  
L. F. Allard ◽  
E. Völkl
Keyword(s):  
Heterogeneous Catalysts ◽  
High Surface ◽  
High Surface Area ◽  
Atomic Scale ◽  
Nano Particles ◽  
Phase Image ◽  
Electron Holography ◽  
Specimen Thickness ◽  
Phase Information ◽  
Particle Structure

The active phase in heterogeneous catalysts consists of nanometer-sized metal or oxide particles dispersed within the tortuous pore structure of a high surface area matrix. Such catalysts are extensively used for controlling emissions from automobile exhausts or in industrial processes such as the refining of crude oil to produce gasoline. The morphology of these nano-particles is of great interest to catalytic chemists since it affects the activity and selectivity for a class of reactions known as structure-sensitive reactions. In this paper, we describe some of the challenges in the study of heterogeneous catalysts, and provide examples of how electron holography can help in extracting details of particle structure and morphology on an atomic scale.Conventional high-resolution TEM imaging methods permit the image intensity to be recorded, but the phase information in the complex image wave is lost. However, it is the phase information which is sensitive at the atomic scale to changes in specimen thickness and composition, and thus analysis of the phase image can yield important information on morphological details at the nanometer level.

scholarly journals One-Dimensional (1D) Nanostructured Materials for Energy Applications

Materials ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2609
Author(s):  
Abniel Machín ◽  
Kenneth Fontánez ◽  
Juan C. Arango ◽  
Dayna Ortiz ◽  
Jimmy De León ◽  
...  
Keyword(s):  
Nanostructured Materials ◽  
Fossil Fuels ◽  
High Surface ◽  
High Surface Area ◽  
Future Research ◽  
One Dimensional ◽  
Progressive Movement ◽  
1D Nanostructures ◽  
Energy Applications ◽  
Energy Processes

At present, the world is at the peak of production of traditional fossil fuels. Much of the resources that humanity has been consuming (oil, coal, and natural gas) are coming to an end. The human being faces a future that must necessarily go through a paradigm shift, which includes a progressive movement towards increasingly less polluting and energetically viable resources. In this sense, nanotechnology has a transcendental role in this change. For decades, new materials capable of being used in energy processes have been synthesized, which undoubtedly will be the cornerstone of the future development of the planet. In this review, we report on the current progress in the synthesis and use of one-dimensional (1D) nanostructured materials (specifically nanowires, nanofibers, nanotubes, and nanorods), with compositions based on oxides, nitrides, or metals, for applications related to energy. Due to its extraordinary surface–volume relationship, tunable thermal and transport properties, and its high surface area, these 1D nanostructures have become fundamental elements for the development of energy processes. The most relevant 1D nanomaterials, their different synthesis procedures, and useful methods for assembling 1D nanostructures in functional devices will be presented. Applications in relevant topics such as optoelectronic and photochemical devices, hydrogen production, or energy storage, among others, will be discussed. The present review concludes with a forecast on the directions towards which future research could be directed on this class of nanostructured materials.

Metal nanoparticles: ligand free approach towards coupling reactions

2021 ◽  
Vol 01 ◽  
Author(s):  
Sharwari K. Mengane ◽  
Ronghui Wu ◽  
Liyun Ma ◽  
Chhaya S. Panse ◽  
Shailesh N. Vajekar ◽  
...  
Keyword(s):  
Heterogeneous Catalysis ◽  
Metal Nanoparticles ◽  
Surface Area ◽  
Heterogeneous Catalysts ◽  
High Surface ◽  
High Surface Area ◽  
Reaction Medium ◽  
Coupling Reactions ◽  
Research Activities ◽  
Ligand Free

: Catalysis is the multidisciplinary field involving many areas of chemistry, notably in organometallic chemistry and materials science. It has great applications in synthesis of many industrially applicable compounds such as fuels and fine chemicals. The activity and selectivity are a key issue in catalysis that generally allied to high surface area. The current research activities mainly deal with the homogeneous and heterogeneous catalysis. Homogeneous and heterogeneous catalysis have certain drawbacks which restricts their application to great extent but have their own advantages. Hence, it has a predominant concern of current research to find out an alternate to overcome their drawbacks. Therefore, it is highly desirable to find a catalytic protocol that offers high selectivity and excellent product yield with quick and easy recovery. Along with their various applications as alternatives to conventional bulk materials nanomaterial have established its great role in different industrial and scientific applications. Nanocatalysis has emerged as new alternative to the conventional homogeneous and heterogeneous catalysis. The nanomaterials are responsible to enhance surface area of the catalyst, which ultimately increases the catalyst reactants contacts. In addition, it acts as robust material and has high surface area like heterogeneous catalysts. Insolubility of such nanomaterial in reaction medium makes them easily separable, hence, catalyst can be easily separate from the product. Hence, it has been proven that nanocatalysts behave like homogeneous as well as heterogeneous catalysts which work as a bridge between the conventional catalytic systems. Considering these merits; researchers has paid their attention towards applications of nanocatalyst in several organic reactions. This review article focused on the catalytic applications of metal nanoparticles (MNPs) such as Pd, Ag, Au, Cu, Pt in ligand free coupling reactions. In addition, it covers applications of bimetallic and multimetallic nanoparticles in ligand free coupling reactions.

scholarly journals The Role of Surface Hydroxylation, Lattice Vacancies and Bond Covalency in the Electrochemical Oxidation of Water (OER) on Ni-Depleted Iridium Oxide Catalysts

2020 ◽  
Vol 234 (5) ◽  
pp. 787-812 ◽  
Author(s):  
Hong Nhan Nong ◽  
Hoang Phi Tran ◽  
Camillo Spöri ◽  
Malte Klingenhof ◽  
Lorenz Frevel ◽  
...  
Keyword(s):  
Metal Oxide ◽  
High Surface ◽  
High Surface Area ◽  
Oxide Shell ◽  
Mixed Metal Oxide ◽  
Support Materials ◽  
Oxide Support ◽  
Rich Alloy ◽  
Surface Hydroxylation

AbstractThe usage of iridium as an oxygen-evolution-reaction (OER) electrocatalyst requires very high atom efficiencies paired with high activity and stability. Our efforts during the past 6 years in the Priority Program 1613 funded by the Deutsche Forschungsgemeinschaft (DFG) were focused to mitigate the molecular origin of kinetic overpotentials of Ir-based OER catalysts and to design new materials to achieve that Ir-based catalysts are more atom and energy efficient, as well as stable. Approaches involved are: (1) use of bimetallic mixed metal oxide materials where Ir is combined with cheaper transition metals as starting materials, (2) use of dealloying concepts of nanometer sized core-shell particle with a thin noble metal oxide shell combined with a hollow or cheap transition metal-rich alloy core, and (3) use of corrosion-resistant high-surface-area oxide support materials. In this mini review, we have highlighted selected advances in our understanding of Ir–Ni bimetallic oxide electrocatalysts for the OER in acidic environments.

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