Search

The development of high-performance nanocatalysts relies essentially on the generation of stable and active surface sites at the atomic scale through synthetic control of the size, shape, and chemical composition of nanoscale metals and metal oxides. One promising route is to induce the exposure of catalytically active high-index facets of nanostructures through shape-controlled syntheses. We have designed and prepared two types of Pd nanoshells that are enclosed by high-index {730} and {221} facets through heteroepitaxial growth on high-index-faceted Au nanocrystals. The turnover numbers per surface atom of the high-index-faceted Pd nanoshells have been found to be 3-7 times those of Pd and Au-Pd core-shell nanocubes that possess only {100} facets in catalyzing the Suzuki coupling reaction. These results open up a potential for the development of inexpensive and highly active metal nanocatalysts.

This article reports a facile and controllable two-step method to construct TiO(2)-Pt@SiO(2) nanocomposites. TiO(2) nanoparticles (NPs), with small size and high surface energy, were synthesized by a solvothermal reaction process. The TiO(2)-Pt@SiO(2) nanocomposites were fabricated by a reverse micro-emulsion method. SiO(2) shell coated NPs were adopted for further photocatalytic reaction. Because of their small size and high surface energy, TiO(2)@SiO(2) and TiO(2)-Pt@SiO(2) nanocomposites show higher photocatalytic activity than commercial Degussa P25. Compared with TiO(2)@SiO(2), TiO(2)-Pt@SiO(2)nanocomposites have improved photocatalytic activity due to the Pt induced spatial separation of electrons and holes. The silica shells not only maintain the structure of the nanocomposites but also prevent their aggregation during the photocatalytic reactions, which is highly important for the good durability of the photocatalyst. This strategy is simple, albeit efficient, and can be extended to the synthesis of other composites of noble metals. It has opened a new window for the construction of hetero-nanocomposites with high activity and durability, which would serve as excellent models in catalytic systems of both theoretical and practical interest.

Bimetallic Pt–Pd nanoicosahedrons (NIs) with multiple {111} twins were obtained through a facile one-pot hydrothermal synthesis in a high shape selectivity of 82%. The {111}-enclosed NIs exhibited superior electrocatalytic activities to {111}-enclosed Pt–Pd nanotetrahedrons as well as commercial Pt catalysts (Pt black and Pt/C) for methanol oxidation.

An effective synthetic strategy is demonstrated for preparing highly ordered crystallized mesoporous TiO(2) by introducing rare earth in the synthesis process; the obtained product exhibits near-infrared photocatalytic activity.

Pt/CeO(2) hetero-nanocomposites were prepared from Pt/CeO(2)@SiO(2) obtained by a microemulsion-mediated method. Facilitated by the earlier calcination under the protection of a silica shell, the as-formed Pt/CeO(2) hetero-nanocomposites exhibit a good thermal stability, which can preserve their pristine properties after subsequent calcination at even 450 degrees C. The thermally stable Pt/CeO(2) hetero-nanocomposites possess the characteristics of small particle size, low aggregation, and maximized Pt/CeO(2) interfaces and thus exhibit high catalytic activity in CO oxidation.

SnO(2) nanorods with specific growth directions, [101] or [001], were fabricated on α-Fe(2)O(3) substrates via a simple hydrothermal method. The growth behavior of SnO(2) nanorods is facet-selective. Both {11 ̅20} and {10 ̅10} facets of α-Fe(2)O(3) are favorable to direct the growth of SnO(2) nanorods. The correlation between the crystallographic orientation of SnO(2) and the facets of α-Fe(2)O(3) is characterized by TEM observations and investigated on the basis of the interfacial lattice compatibility. Furthermore, the distribution and coordination of oxygen atoms at the interface of α-Fe(2)O(3)-SnO(2) heterostructure are analyzed, which reveals that only slight deviations from their original equilibrium positions are allowed for the formation of heterogeneous interface. And this lower energy activated interfacial construction is beneficial to the feasibility and stability of heterostructures.