Xiangwen Liu

Mesoporous Multicomponent Nanocomposite Colloidal Spheres: Ideal High‐Temperature Stable Model Catalysts

Insupported noble-metal catalysts the metal particles tend toaggregate during the reaction process, and the particle sizethus becomes larger which leads to lower catalytic activity.Additionally, the metal particles usually detach from thesupport when the corresponding catalyst is rubbed recipro-cally, which results in a sharp decrease of the active sites.Therefore, the design of an ideal nanostructure for supportednoble-metal catalysts that can overcome the above-men-tioned limits and, thus, display high stability, is a greatchallenge in this field.

Pt–Ni nanodendrites with high hydrogenation activity

Bimetallic highly branched Pt-Ni nanocrystals were obtained by a one-pot strategy. The dendritic alloyed structure of the as-prepared nanoparticles was fully characterized and their formation mechanism was investigated. Nitrobenzene hydrogenation reactions indicated that these obtained Pt-Ni nanodendrites exhibited enhanced catalytic activities compared with Pt-Ni nanoparticles.

One-Pot Protocol for Bimetallic Pt/Cu Hexapod Concave Nanocrystals with Enhanced Electrocatalytic Activity

Nanomaterials with particular nanostructures which usually possess special properties always attract considerable attention. A novel bimetallic Pt/Cu hexapod nanostructure was prepared by a facile one-pot strategy. The formation mechanism was investigated by the time sequential evolution experiments and the hexapod concave nanostructures originated from the Pt/Cu rhombic dodecahedron. Further electrochemical measurements indicated the bimetallic Pt/Cu hexapod concave nanocrystals showed enhanced catalytic activities. It is believed that these novel nanostuctures would open up new opportunities for catalytic applications.

Directly assembling ligand-free ZnO nanocrystals into three-dimensional mesoporous structures by oriented attachment.

Mesoporous materials have found a great number of important utilities due to their well-defined pore structure and high internal surface area, which are routinely synthesized with the assistance of block copolymers or templates. So far, a key challenge is how to assemble directly ligand-free inorganic nanocrystals into mesoporous structures, so that the high surface activity of ligand-free nanocrystals is not destroyed by further treatment to remove organic species or templates. In this paper, we report the direct assembly of highly uniform ZnO mesoporous ellipsoids from ligand-free ZnO nanocrystals of ∼5 nm. The size of the synthesized uniform ZnO mesoporous ellipsoids can be efficiently tuned from 132 × 75 to 190 × 111 nm (length × width), by varying the size and concentration of primary ZnO nanocrystal building blocks and the composition of the designed assembling solvent. The BET detection indicates that these ZnO mesoporous ellipsoids have high specific surface areas reaching to 136.57 m(2)/g, while their average BJH pore diameters are located at 8.8 nm. Especially, the high-resolution TEM images and XRD analysis revealed the occurrence of an oriented attachment mechanism in the assembly of uniform ZnO mesoporous ellipsoids, which supplied an important proof for the possibility of constructing stable three-dimensional structures by oriented attachment. The benefits of these ZnO mesoporous ellipsoids were demonstrated by their excellent photocatalytic activity under weak UV irradiation.

One-pot synthesis of monodisperse CeO2 nanocrystals and superlattices.

Monodisperse CeO(2) nanocrystals and superlattice-like colloidal particles have been successfully synthesized in ethanol-water mixed solvent by adopting a one-pot approach using icosahedral (NH(4))(2)Ce(NO(3))(6) as precursor.

Intermetallic NixMy (M = Ga and Sn) Nanocrystals: A Non-precious Metal Catalyst for Semi-Hydrogenation of Alkynes

Intermetallic Nix My (M = Ga and Sn) nanocrystals with uniform particle size and controlled composition are successfully synthesized via a solution-based co-reduction strategy. The as-obtained nanocrystals are crystalline and structurally ordered. The active-site isolation and modified electronic structure are responsible for the excellent catalytic performance for alkyne semi-hydrogenation of the as-obtained non-precious catalysts.

C/N-sensitized self-assembly of mesostructured TiO2 nanospheres with significantly enhanced photocatalytic activity

Uniformly carbonaceous and nitrogenous species sensitized TiO2 quantum dots (QDs, ∼4 nm) were synthesized through an improved strategy employing an oleic acid and oleylamine system, and were further assembled into the mesoporous structure of C/N-TiO2 nanospheres via an emulsion-based bottom-up self-assembly (EBS). EBS not only transformed oil-soluble C/N-TiO2 QDs into water-soluble nanospheres, but also assembled them into mesostructures with an average diameter around 200 nm. The photocatalytic properties of the as-prepared C/N-TiO2 QDs and C/N-TiO2 nanospheres were evaluated by measuring the photodegradation of rhodamine B (RhB) under visible-light irradiation. Compared to C/N-TiO2 QDs and commercial product P25, the experimental results showed that the water miscible mesostructured C/N-TiO2 nanospheres with improved effective catalytic area and RhB adsorption, and a red shift of the absorption edge to the visible light region, possessed improved photocatalytic activity. The purpose of this study is to illustrate the importance of C/N-species sensitization and fundamental structural control in effecting the photodegradation property of TiO2-based catalysts.