Wensheng Ning

A sandwich N-doped graphene/Co3O4 hybrid: an efficient catalyst for selective oxidation of olefins and alcohols

A sandwich-like N-doped graphene/Co3O4 hybrid was prepared via a simple one-pot hydrothermal reaction in a solution of NH3. Characterizations disclosed that highly dispersed Co3O4 nanoparticles with dominant exposed {112} and {110} planes were fabricated on both sides of well-exfoliated N-doped graphene; N-dopants in the graphene matrix can prevent re-graphitization of graphene, strengthen the interaction between Co3O4 and the graphene matrix, and improve the dispersion of Co3O4. This hybrid (Co3O4/RGO-N) exhibited superior activity and stability for the epoxidation of styrene compared to bulk Co3O4 and N-free graphene supported Co3O4. At the same time, the resulting catalyst also showed high compatibility with various olefins and alcohols with good conversion and high selectivity. This synergistic strategy can provide simple, efficient and versatile blue-prints for low-cost fabrication of graphene-based nanocomposites for extending applications where graphene has rarely been exploited and beyond.

SnO2-isolated Pt3Sn alloy on reduced graphene oxide: an efficient catalyst for selective hydrogenation of CO in unsaturated aldehydes

In this communication, a pyramid shaped alloy-metal oxide–graphene hybrid was synthesized by a facile procedure, in which SnO2 nanoparticles (NPs) (4.8–5.8 nm) were first coated onto the surface of reduced graphene oxide (rGO), and then very fine Pt3Sn NPs (0.6–1.2 nm) were fabricated on the SnO2 NPs on rGO sheets under microwave irradiation in a few minutes. Characterizations disclosed that the SnO2 NPs on rGO were more favorable for the dispersion of Pt, and Pt3Sn formed mainly on the surface of SnO2 NPs. This pyramid shaped Pt3Sn/SnO2/rGO hybrid was highly active, selective and stable for the hydrogenation of the CO bond in unsaturated aldehydes to unsaturated alcohols under mild conditions.

Multiwall carbon nanotube-pillared layered Cu0.4/Mg5.6Al2O8.6: an efficient catalyst for hydrogenolysis of glycerol

Multiwall carbon nanotube (MWCNT)-pillared layered Cu0.4/Mg5.6Al2O8.6 material with doublet meso-pore channels and higher surface area was fabricated and used in hydrogenolysis of glycerol. The activity of surface Cu in MWCNTs–Cu0.4/Mg5.6Al2O8.6 hybrid is higher than those of Pd- and Rh-promoted Cu0.4/Mg5.6Al2O8.6 catalysts.

Selective glycerol oxidation using platinum nanoparticles supported on multi-walled carbon nanotubes and nitrogen-doped graphene hybrid

Abstract Selective oxidation of glycerol is a hot topic. Increased biodiesel production has led to glycerol oxidation over Au- and Pt-based catalysts being widely studied. However, Pt catalysts suffer from deactivation because of weak metal-support interactions. In this study, multi-walled carbon nanotube (MWCNTs)-pillared nitrogen-doped graphene (NG) was prepared by direct pyrolysis of melamine on MWCNTs, and the synthesized NG-MWCNT composite was used as the support for Pt. Characterization results showed that the surface area (173 m 2 /g) and pore volume of the NG-MWCNT composite were greater than those of bare MWCNTs and the separated melamine pyrolysis product (CN x ). Pt (1.4 ± 0.4 nm) dispersion on the NG-MWCNTs was favorable and the Pt/NG-MWCNT catalyst was highly active and selective in the oxidation of glycerol to glyceric acid (GLYA) in base-free aqueous solution. For example, the conversion of glycerol reached 64.4% with a GLYA selectivity of 81.0%, whereas the conversions of glycerol over Pt/MWCNTs and Pt/CN x were 29.0% and 31.6%, respectively. The unique catalytic activity of the Pt/NG-MWCNTs is attributed to well-dispersed Pt clusters on the NG-MWCNTs and the electron-donating effect of the nitrogen dopant in the NG-MWCNTs.

To Synthesize Liquid Fuels on Precipitated Fe Catalyst with CO2-Containing Syngas Gasified from Biomass

Fischer–Tropsch (FT) synthesis is an effective method to produce liquid fuels from biomass. This chapter reports the study on precipitated Fe catalysts for conversion of CO2-containing syngas to liquid fuels. The influences of promoter Zn, K, and Cu on CO2 activation were analyzed by CO2 temperature-programmed- desorption (CO2-TPD). Cu has no strong effect to activate CO2. K increases mainly CO2 adsorption and is inferior to Zn in producing CO. The catalysts with high Zn/K ratio or low K content possess desorbed CO peak around 930 K in CO2-TPD and decreased CO2 selectivity resulted from CO2 addition in FT synthesis. The Fe catalyst with high Zn/K ratio shows high C2+ hydrocarbon selectivity for CO2 hydrogenation, too. It indicates that the CO2 contained in syngas is able to be activated by suitable promoter(s) for hydrocarbon synthesis at low temperature. The correlation between promoter composition and catalyst reactivity found for SiO2-free Fe catalysts is effective for SiO2-added Fe catalysts.