Showing papers by "Xiaobin Fan published in 2013"

Nanoporous Ni(OH)2 thin film on 3D Ultrathin-graphite foam for asymmetric supercapacitor.

Abstract: Nanoporous nickel hydroxide (Ni(OH)2) thin film was grown on the surface of ultrathin-graphite foam (UGF) via a hydrothermal reaction. The resulting free-standing Ni(OH)2/UGF composite was used as the electrode in a supercapacitor without the need for addition of either binder or metal-based current collector. The highly conductive 3D UGF network facilitates electron transport and the porous Ni(OH)2 thin film structure shortens ion diffusion paths and facilitates the rapid migration of electrolyte ions. An asymmetric supercapacitor was also made and studied with Ni(OH)2/UGF as the positive electrode and activated microwave exfoliated graphite oxide (‘a-MEGO’) as the negative electrode. The highest power density of the fully packaged asymmetric cell (44.0 kW/kg) was much higher (2–27 times higher), while the energy density was comparable to or higher, than high-end commercially available supercapacitors. This asymmetric supercapacitor had a capacitance retention of 63.2% after 10 000 cycles.

Graphene-Encapsulated Si on Ultrathin-Graphite Foam as Anode for High Capacity Lithium-Ion Batteries

Abstract: A Si/graphene composite is drop-casted on an ultrathin-graphite foam (UGF) with three dimensional conductive network. The Si/graphene/UGF composite presents excellent stability and relatively high overall capacity when tested as an anode for rechargeable lithium ion batteries.

Primary and tertiary amines bifunctional graphene oxide for cooperative catalysis

Abstract: In this study, primary and tertiary amine bifunctional graphene oxide (GO–NH2–NEt2) was prepared by silylanization of graphene oxide (GO) with amine-terminal silanes. The obtained GO–NH2–NEt2 was characterized by infrared spectrum (FTIR), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), high-resolution transmission electron microscopy (HRTEM) and X-ray photoelectron spectroscopy (XPS). Systematic studies demonstrated the GO–NH2–NEt2 had excellent catalytic activities and 100% selectivity in the classic trans-β-nitrostyrene forming reaction.

Rhodium complex immobilized on graphene oxide as an efficient and recyclable catalyst for hydrogenation of cyclohexene

Abstract: Rhodium complexes can be homogeneously immobilized on functionalized graphene oxide through coordination interaction. The obtained catalyst can be readily recycled and shows enhanced activity in the catalytic hydrogenation of cyclohexene.

Enhanced hydrogenation of olefins and ketones with a ruthenium complex covalently anchored on graphene oxide

Abstract: Graphene oxide (GO) is a promising support for anchoring homogeneous metal complexes because of its two-dimensional structure, huge surface area and diversity for chemical functionalizations. In this study, a ruthenium supported catalyst has been synthesized by covalently bonding a ruthenium complex (RuCl2(PPh3)3) onto the GO surface through coordination interaction with aminosilane ligand spacers. The supported catalyst showed enhanced catalytic performance towards hydrogenation of olefins and ketones compared with the homogeneous analogue, and it could be readily recycled and reused several times without discernible loss of its activity.

Cooperative catalysis by acid–base bifunctional graphene

Abstract: Acid–base bifunctional catalysts are of particularly interest, but also present great challenges in synthesis and applications. In this study, acid–base bifunctional graphene oxide hybrids were obtained by the modification of graphene oxide (GO) through a silylation reaction and radical addition. The obtained bifunctional hybrids displayed high acid and base catalytic activities towards a typical one-pot acid–base reaction sequence called deacetalization–nitroaldol reaction.

A graphene-based smart catalytic system with superior catalytic performances and temperature responsive catalytic behaviors.

Abstract: We have successfully developed a unique graphene-based smart catalytic system which consists of the graphene supported Au–Pt bimetallic nanocatalyst with a well-defined core–shell structure and a dextran-based temperature-responsive polymer. The unique catalytic system possesses excellent catalytic performances and the catalytic activities could be readily switched on or off at different temperature windows.

Thermo-sensitive graphene supported gold nanocatalyst: synthesis, characterization and catalytic performance

Abstract: Graphene has attracted increasing attention as a support for heterogeneous catalysis Although successful preparation and excellent catalytic performance of many graphene based nanocatalysts have been demonstrated, graphene supported nanocatalysts with turnable catalytic behaviors remain unexplored In this study, we report a strategy to prepare a graphene supported Au nanocatalyst with thermo-sensitive catalytic behaviors This smart catalytic system was prepared by introducing the temperature-responsive poly(N-isopropylacrylamide) (NIPAAm) and Au nanoparticles to graphene oxide (GO) through reversible addition–fragmentation chain transfer polymerization and direct co-reduction of HAuCl4 The obtained GO–NIPAAm–Au hybrid was systematically characterized and showed interesting thermo-sensitive catalytic activity in the catalytic reduction of 4-nitrophenol

Functionalization of graphene with nitrile groups by cycloaddition of tetracyanoethylene oxide

Abstract: Graphene has got considerable attention in both experimental and theoretical fields for its extraordinary properties. Covalent functionalization is an efficient strategy to render graphene additional properties and overcome its shortcomings such as zero band gap and nondispersibility in solvents. This study reports the synthesis and characterizations of a new kind of functionalized graphene, graphene-TCNEO, obtained by 1,3-dipolar cycloaddition. The graphene-TCNEO was systematically characterized by FTIR, Raman, XPS, SEM, TEM, and EDS mapping, and the covalent linkage between graphene and tetracyanoethylene oxide was firmly verified. Considering the great diversity of nitrile chemistry, the obtained graphene-TCNEO could be further transformed into other graphene-based derivatives with interesting properties.

Graphene Supported Pt/Ni Nanoparticles as Magnetically Separable Nanocatalysts

Abstract: Efficient recovery of nanocatalysts, especially the graphene supported noble metal catalysts, is a challenge. In this study, we report a simple one-step route to prepare the graphene supported Pt/Ni nanocatalysts with ideal superparamagnetic properties. We demonstrated that they had excellent catalytic activities in the catalytic reduction of aromatic nitro compounds and could be easily separated from the reaction mixtures by applying an external magnetic field.