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Journal ArticleDOI

Catalytic dry reforming of methane over high surface area ceria

TL;DR: In this article, high surface area ceria (CeO 2) was synthesized by a surfactant-assisted approach, which has useful dry reforming activity for H 2 and CO production under solid oxide fuel cells (SOFCs) conditions.
Abstract: High surface area ceria (CeO 2 (HSA)), synthesized by a surfactant-assisted approach, was found to have useful dry reforming activity for H 2 and CO production under solid oxide fuel cells (SOFCs) conditions. The catalyst provides significantly higher reforming reactivity and excellent resistance toward carbon deposition compared to Ni/Al 2 O 3 and conventional low surface area ceria (CeO 2 (LSA)) under dry reforming conditions. These enhancements are due to the high redox property of CeO 2 (HSA). During the dry reforming process, the redox reactions between the gaseous components in the system and the lattice oxygen (O x ) take place on ceria surface. Among these reactions, the rapid redox reactions of carbon compounds such as CH 4 , and CO with lattice oxygen (CH 4 + O x → CO + H 2 + O x −1 and CO + O x = CO 2 + O x −1 ) can prevent the formation of carbon species from the methane decomposition and Boudard reactions even at low inlet carbon dioxide concentration. In particular, the dry reforming rate over CeO 2 (HSA) is proportional to the methane partial pressure and the operating temperature. Carbon dioxide presents weak positive impact on the methane conversion, whereas both carbon monoxide and hydrogen inhibit the reforming rate. The activation energies and reforming rates under the same methane concentration for CeO 2 toward the dry reforming are almost equal to the steam reforming as previously reported [1–4] . This result suggests the similar reaction mechanisms for both the steam reforming and the dry reforming over CeO 2 ; i.e., the dry reforming rate is governed by the slow reaction of adsorbed methane, or surface hydrocarbon species, with oxygen in CeO 2 , and a rapid gas–solid reaction between CO 2 and CeO 2 to replenish the oxygen.
Citations
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Journal ArticleDOI
TL;DR: This review has a wide view on all those aspects related to ceria which promise to produce an important impact on the authors' life, encompassing fundamental knowledge of CeO2 and its properties, characterization toolbox, emerging features, theoretical studies, and all the catalytic applications, organized by their degree of establishment on the market.
Abstract: Cerium dioxide (CeO2, ceria) is becoming an ubiquitous constituent in catalytic systems for a variety of applications. 2016 sees the 40th anniversary since ceria was first employed by Ford Motor Company as an oxygen storage component in car converters, to become in the years since its inception an irreplaceable component in three-way catalysts (TWCs). Apart from this well-established use, ceria is looming as a catalyst component for a wide range of catalytic applications. For some of these, such as fuel cells, CeO2-based materials have almost reached the market stage, while for some other catalytic reactions, such as reforming processes, photocatalysis, water-gas shift reaction, thermochemical water splitting, and organic reactions, ceria is emerging as a unique material, holding great promise for future market breakthroughs. While much knowledge about the fundamental characteristics of CeO2-based materials has already been acquired, new characterization techniques and powerful theoretical methods are dee...

1,710 citations

Journal ArticleDOI
TL;DR: In this article, the development of CO2 reforming for syngas production is reviewed, covering process chemistry, catalyst development, and process technologies as well as the potential future direction for this process.
Abstract: The mitigation and utilization of greenhouse gases, such as carbon dioxide and methane, are among the most important challenges in the area of energy research. Dry reforming of CH4 (DRM), which uses both CO2 and CH4 as reactants, is a potential method to utilize the greenhouse gases in the atmosphere. Natural gas containing high concentrations of CO2 and CH4 could therefore be utilized for hydrogen and synthesis gas (syngas) production in the near future, without need for the removal of CO2 from the source gas. Thus, the DRM reaction is a suitable process to convert CH4 and CO2 to syngas, which is a raw material for liquid fuel production, through the Fischer–Tropsch process. Herein, the development of CO2 reforming for syngas production is reviewed, covering process chemistry, catalyst development, and process technologies as well as the potential future direction for this process.

496 citations

Journal ArticleDOI
Xianjun Du1, Dengsong Zhang1, Liyi Shi1, Ruihua Gao1, Jianping Zhang1 
TL;DR: In this paper, the comparative catalytic activity and coke resistance of Ni/CeO2 nanorods (NR) and nanopolyhedra (NP) were examined in carbon dioxide reforming of methane over Ni/NiO2-NR catalysts and showed that the predominantly exposed planes are the unusually reactive {110 and {100} planes on the CeO2−NR rather than the stable {111} one on the NiO2•NP.
Abstract: The comparative catalytic activity and coke resistance are examined in carbon dioxide reforming of methane over Ni/CeO2 nanorods (NR) and nanopolyhedra (NP). The Ni/CeO2–NR catalysts display more excellent catalytic activity and higher coke resistance compared with the Ni/CeO2–NP. The high resolution transmission electron microscope reveals that the predominantly exposed planes are the unusually reactive {110} and {100} planes on the CeO2–NR rather than the stable {111} one on the CeO2–NP. The prepared samples were also characterized by X-ray diffraction, transmission electron microscopy, hydrogen temperature-programmed reduction, X-ray photoelectron spectroscopy, UV and visible Raman spectra, and oxygen temperature-programmed oxidation. The {110} and {100} planes show great superiority for the anchoring of Ni nanoparticles, which results in the existence of strong metal–support interaction effect (SMSI). The SMSI effect can be helpful to prevent sintering of Ni particles, which benefits to reduce the dea...

440 citations

Journal ArticleDOI
TL;DR: In this paper, a review provides a contemporary assessment of progresses recorded on synergistic interplay among catalyst components (active metals, support, promoters and binders) during dry reforming using state-of-the-art experimental and theoretical techniques.
Abstract: The abrupt and massive deactivation of methane dry reforming catalysts especially Ni-based is still a monumental impediment towards its industrialization and commercialization for production of value-added syngas via Fischer-Tropsch process. The need for further and more critical understanding of inherent and tailored interactions of catalyst components for performance and stability enhancement during reforming reaction cannot be over-emphasized. This review provides a contemporary assessment of progresses recorded on synergistic interplay among catalyst components (active metals, support, promoters and binders) during dry reforming using state-of-the-art experimental and theoretical techniques. Advancements achieved during interplay leading to improvements in properties of existing catalysts and discovery of novel ones were stated and expatiated. Reaction pathways, catalytic activities, selection of appropriate synthesis route and metal/support deactivation via sintering or carbon deposition have over time been successfully studied and explained using information from these crucial component interactions. This perspective describes the roles of these interactions and their applications towards development of robust catalysts configurations for successful industrial applications.

367 citations

Journal ArticleDOI
TL;DR: In this short review, attention will be given to the thermodynamics of dry reforming followed by an investigation on dry reforming using heterogeneous catalyst by focusing on the most popular elements used in literature for dry reforming.
Abstract: With the actual growth of the natural gas industry in the US as well as the potential and availability of this non-renewable carbon source worldwide, reforming of methane gas is getting increasing attention. Methane can be used for the production of heat or electricity, as well, it can be converted to syngas, a building block that could lead to the production of liquid fuels and chemical, a very promising pathway in light of the increasing price of oil. Amongst the different reforming techniques, dry reforming could represent a very interesting approach both to valorize a cheap source or carbon (CO2) as well as to reduce the overall carbon footprint of the increasing worldwide fossil-based methane consumption. In this short review, attention will be given on the thermodynamics of dry reforming followed by an investigation on dry reforming using heterogeneous catalyst by focusing on the mots popular elements used in literature for dry reforming. Attention will as well be given to different other emerging techniques that may allow countering at one point the high thermodynamic penalties that accompanies conversion of methane using carbon dioxide.

362 citations


Cites background from "Catalytic dry reforming of methane ..."

  • ...Laosiripojana and Assabumrungrat reported on the utilization of high and low-surface ceria (CeO2) for the DRM reaction at different CH4/CO2 ratios and compared the performance on Ni/Al2O3 catalyst (Laosiripojana and Assabumrungrat, 2005)....

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References
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Journal ArticleDOI
22 Oct 1992-Nature
TL;DR: In this paper, the synthesis of mesoporous inorganic solids from calcination of aluminosilicate gels in the presence of surfactants is described, in which the silicate material forms inorganic walls between ordered surfactant micelles.
Abstract: MICROPOROUS and mesoporous inorganic solids (with pore diameters of ≤20 A and ∼20–500 A respectively)1 have found great utility as catalysts and sorption media because of their large internal surface area. Typical microporous materials are the crystalline framework solids, such as zeolites2, but the largest pore dimensions found so far are ∼10–12 A for some metallophosphates3–5 and ∼14 A for the mineral cacoxenite6. Examples of mesoporous solids include silicas7 and modified layered materials8–11, but these are invariably amorphous or paracrystalline, with pores that are irregularly spaced and broadly distributed in size8,12. Pore size can be controlled by intercalation of layered silicates with a surfactant species9,13, but the final product retains, in part, the layered nature of the precursor material. Here we report the synthesis of mesoporous solids from the calcination of aluminosilicate gels in the presence of surfactants. The material14,15 possesses regular arrays of uniform channels, the dimensions of which can be tailored (in the range 16 A to 100 A or more) through the choice of surfactant, auxiliary chemicals and reaction conditions. We propose that the formation of these materials takes place by means of a liquid-crystal 'templating' mechanism, in which the silicate material forms inorganic walls between ordered surfactant micelles.

15,125 citations

Journal ArticleDOI
24 Mar 1994-Nature
TL;DR: In this article, a generalized approach to the synthesis of periodic mesophases of metal oxides and cationic or anionic surfactants under a range of pH conditions is presented.
Abstract: THE recent synthesis of silica-based mesoporous materials1,2 by the cooperative assembly of periodic inorganic and surfactant-based structures has attracted great interest because it extends the range of molecular-sieve materials into the very-large-pore regime. If the synthetic approach can be generalized to transition-metal oxide mesostructures, the resulting nanocomposite materials might find applications in electrochromic or solid-electrolyte devices3,4, as high-surface-area redox catalysts5 and as substrates for biochemical separations. We have proposed recently6 that the matching of charge density at the surfactant/inorganic interfaces governs the assembly process; such co-organization of organic and inorganic phases is thought to be a key aspect of biomineralization7. Here we report a generalized approach to the synthesis of periodic mesophases of metal oxides and cationic or anionic surfactants under a range of pH conditions. We suggest that the assembly process is controlled by electrostatic complementarity between the inorganic ions in solution, the charged surfactant head groups and—when these charges both have the same sign—inorganic counterions. We identify a number of different general strategies for obtaining a variety of ordered composite materials.

1,996 citations

Journal ArticleDOI
10 Feb 1995-Science
TL;DR: A neutral templating route for preparing mesoporous molecular sieves is demonstrated based on hydrogen-bonding interactions and self-assembly between neutral primary amine micelles (S�) and neutral inorganic precursors (l�).
Abstract: A neutral templating route for preparing mesoporous molecular sieves is demonstrated based on hydrogen-bonding interactions and self-assembly between neutral primary amine micelles (S degrees ) and neutral inorganic precursors (l degrees ). The S degrees l degrees templating pathway produces ordered mesoporous materials with thicker framework walls, smaller x-ray scattering domain sizes, and substantially improved textural mesoporosities in comparison with M41S materials templated by quaternary ammonium cations of equivalent chain length. This synthetic strategy also allows for the facile, environmentally benign recovery of the cost-intensive template by simple solvent extraction methods. The S degrees 1 degrees templating route provides for the synthesis of other oxide mesostructures (such as aluminas) that may be less readily accessible by electrostatic templating pathways.

1,733 citations

Journal ArticleDOI
TL;DR: In this article, the organization of cationic or anionic organic and inorganic molecular species to produce three-dimensional periodic biphase arrays is described, which uses cooperative nucleation of molecular inorganic solution species with surfactant molecules and their assembly a t low temperatures into liquid-crystal-like arrays.
Abstract: The organization of cationic or anionic organic and inorganic molecular species to produce three-dimensional periodic biphase arrays is described. The approach uses cooperative nucleation of molecular inorganic solution species with surfactant molecules and their assembly a t low temperatures into liquid-crystal-like arrays. The organic/inorganic interface chemistry makes use of four synthesis routes with @+I-), @-I+), (S+X-I+), and (S-M+I-) direct and mediated combinations of surfactant (cationic S+, anionic S-) and soluble inorganic (cationic I+, anionic I-) molecular species. The concepts can be widely applied to generate inorganic oxide, phosphate or sulfide framework compositions. Distinct lamellar, cubic silica mesophases were synthesized in a concentrated acidic medium (S+X-I+), with the hexagonal and the cubic phases showing good thermal stability. For the hexagonal mesostructured silica materials high BET surface areas (>lo00 m2/g) are found. Hexagonal tungsten(V1) oxide materials were prepared in the presence of quaternary ammonium surfactants in the pH range 4-8. Cubic (Iu3d) and hexagonal antimony(V) oxides were obtained by acidifying (pH = 6-7) homogeneous solutions of soluble Sb(V) anions and quaternary ammonium surfactants a t room temperature @+I-). Using anionic surfactants, hexagonal and lamellar lead oxide mesostructures were found (S-I+). Crystalline zinc phosphate lamellar phases were obtained a t low synthesis temperatures (4 \"C) and lamellar sulfide phases could be also readily generated a t room temperature. The synthesis procedure presented is relevant to the coorganization of organic and inorganic phases in biomineralization processes, and some of the biomimetic implications are discussed.

1,379 citations

Journal ArticleDOI
TL;DR: A review of the use of catalysis for the current and future production of H2 can be found in this article, where a number of different, largely catalytic approaches for producing H2 are described.
Abstract: This review describes a number of different, largely catalytic approaches for producing H2. Since a major fraction of the world's H2 is produced by catalytic processes, involving multiple steps with different types of catalysts, it is clear that catalysis plays a critical role in the production of H2. This review is focused on the use of catalysis for the current and future production of H2. Some background will be provided to give a perspective of the dramatic change in the supply and demand for H2 in the past decade, followed by a review of how it is produced commercially, with a view to how multiple types of catalysis contribute to the total process for H2 production. Steam methane reforming, the major approach for H2 manufacture, will be a focal point for most of the discussion in pointing out the large number of catalytic steps that are used in this major technology. Finally, some alternative catalytic approaches for H2 production will be described.

794 citations