Playing with Structures at the Nanoscale: Designing Catalysts by Manipulation of Clusters and Nanocrystals as Building Blocks (original) (raw)

Creating and mastering nano-objects to design advanced catalytic materials

Coordination Chemistry Reviews, 2011

New developments in the synthesis of nano-materials have opened new possibilities for creating and mastering nano-objects in order to design novel advanced catalytic materials. This concise conceptual review will give a glimpse into this fast growing research area discussing some of the possibilities in this direction, the perspectives and the gap to reduce to develop selective catalysts for complex multistep reactions. Emphasis is given to the opportunities offered by a tailored nano-design of the catalysts, from exploiting nano-confinement effects and supramolecular active sites synergies in nano-reactors to the new possibilities offered by new concepts such as the reduction of the relaxation time between two consecutive turnover cycles on a single active site and forcing a vectorial active site sequence in complex, multistep reactions. Other aspects discussed include the development of hierarchic pore structure to maximize catalyst effectiveness, metal complexes confined with solid cavities and the concept of nano-reactors, nanostructured composites and ordered 1D-type metal oxides. It is shown how significant progress in nano-materials has still not corresponded with progress in understanding the relationship between nanostructure and catalytic performance and the development of a more general strategy on the design of next-generation nano-catalysts.

A Survey on Recent Developments in Catalysis Using Nanostructured Materials

This review describes that nanomaterials have received more attention by virtue of their excellent properties suited for applications in various fields such as electronic, pharmaceutical, biomedical, cosmetic, energy, and catalysis. Nanomaterial-based catalysts are usually heterogeneous catalysts. The extremely small size of the particles maximizes surface area exposed to the reactant, allowing more reactions to occur. However, thermal stability of these nanomaterials is limited by their critical sizes; the smaller the crystallite size, the lower thermal stability. The majority of industrial catalysts contain an active component in the form of nanoparticles smaller than 20nm in size that are dispersed onto high-surface-area supports. The importance of nanoparticles and nanostructure to the performance of catalysts has stimulated wide efforts to develop methods for their synthesis and characterization. Nanoparticles offer higher catalytic efficiency per gram than larger size materials due to their large surface-to-volume ratio. This makes them an attractive choice to use as catalysts. Indeed, catalysts are undoubtedly "the most successful current application of nanotechnology". In the first part of the paper, application of catalysis using nanostructured material in some reactions including alkylation, dehydrogenation, hydrogenation, Steam reforming of methane (SRM), carbon dioxide reforming (DRM), epoxidation of alkenes and oxidative coupling of methane to ethylene (OCM) are investigated. In the second part of the paper, properties of some chemical elements such as gold, silver, platinum, palladium, nickel and rhodium as nanocatalyst are studied. Our investigation shows that the metal nanoparticles can act as best catalyst for industrial application as these have large surface to volume ratio and have unique quantum size effect. Moreover, their homogeneous size distribution with the mean particle size is optimal for catalytic properties and also they increase conversion reactions. Finally, it is shown that despite some disadvantages in using nanostructured materials in catalysts such as high synthesis precise of them and also restriction in industrial usages, they have several prominent advantages which convince everyone to use nanomaterials as catalysts. In addition, this area of study is still interesting for researcher all over the world to extend application of nanostructured catalysis to all reactions which needs catalysts and also reduce synthesis price and solve other problems of using these kinds of catalysts in industrial applications.

Nanomaterials in Catalysis Applications

Catalysts

The interconnected rapid development of nanomaterials science and advanced analysis and imaging techniques at the nano-level scale (some “operando”) fostered the parallel growth of heterogeneous catalysis and its evolution into “nano-catalysis” [...]

Colloid Science of Metal Nanoparticle Catalysts in 2D and 3D Structures. Challenges of Nucleation, Growth, Composition, Particle Shape, Size Control and Their Influence on Activity and Selectivity

Topics in Catalysis, 2008

Recent breakthroughs in the synthesis of nanosciences have achieved the control of size and shape of nanoparticles that are relevant for catalyst design. In this article, we review advances in the synthesis of nanoparticles, fabrication of two-and three-dimensional model catalyst systems, characterization, and studies of activity and selectivity. The ability to synthesize monodispersed platinum and rhodium nanoparticles 1-10 nm in size permitted us to study the influence of composition, structure, and dynamic properties of monodispersed metal nanoparticles on chemical reactivity and selectivity. We review the importance of the size and shape of nanoparticles to determine reaction selectivity in multi-path reactions. The influence of metal-support interaction has been studied by probing the hot electron flows through the metal-oxide interface in catalytic nanodiodes. Novel designs of nanoparticle catalytic systems are also discussed.