Search

Abstract: Composite of multi-walled carbon nanotubes (MWNTs) and titanium (IV) oxide (TiO2) were prepared by a heterogeneous gelation method. The activities of the MWNTs/TiO2 composites were evaluated by photocatalytic oxidative desulfurization using dibenzothiophene (DBT), 4,6-dimethyl dibenzothiophene (4,6-DMDBT), n-tetradecane, and commercial diesel under irradiation using a high-pressure Hg lamp. The microstructures of MWNTs/TiO2 composites were characterized by N2 adsorption, scanning electron microscopy, transmission electron microscope, and X-ray diffraction. It was found that more than 98% of sulfur compounds in commercial diesel were oxidized and removed by the use of the MWNTs/TiO2 composite as a photocatalyst. [Copyright &y& Elsevier]

The synthesis processes of Platinum (Pt) on reduced graphene oxide (rGO) catalysts from graphene oxide (GO) using two reducing agents including sodium borohydride and ethylene glycol is reported. Structure and morphology of Pt/rGO catalysts are characterized by X-ray powder diffraction, transmission electron microscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy. Electrocatalytic methanol oxidation properties of these catalysts are evaluated by cyclic voltammetry and chronoamperometry. The results show that catalyst synthesized using sodium borohydride has a higher metallic Pt content and an improved catalytic performance in comparison to catalyst synthesized using ethylene glycol. Moreover, effect of Pt loading amount on electrocatalytic methanol oxidation performance of catalysts synthesized using sodium borohydride is systematically investigated. The optimal Pt loading amount on graphene is determined to be 40%. [ABSTRACT FROM AUTHOR]

In this work, Pt-SiO 2 /graphene nanocomposites have been synthesized under solvothermal conditions and investigated as electrocatalysts for methanol oxidation. Structure and morphology of these catalysts are characterized by transmission electron microscopy, X-ray diffraction, Raman spectroscopy, X-ray photoelectron spectroscopy and nitrogen adsorption/desorption studies. The Pt and SiO 2 contents of these nanocomposites are determined by inductively coupled plasma optical emission spectrometry (ICP-OES). Their electrocatalytic properties are investigated by cyclic voltammetry, chronoamperometry, chronopotentiometry and electrochemical impendence spectroscopy. The as-prepared nanocomposites show the improved catalytic performance, better stability and good antiposoining ability compared with Pt supported on graphene catalyst. Particularly, the catalyst containing 9.24% of SiO 2 exhibits the best electrocatalytic performance for methanol oxidation with mass activity of 1047 mA mg −1 . [ABSTRACT FROM AUTHOR]

Hybrid materials comprising of Pt dispersed on AlOOH, SiO 2 doped graphene are successfully synthesized. The structure and morphology of the catalysts are characterized by X-ray diffraction, TEM, HRTEM and X-ray photoelectron spectroscopy. Their electrocatalytic properties are investigated by cyclic voltammetry, chronoamperometry and chronopotentiometry. The experimental results show that the presence of AlOOH and SiO 2 favors the Pt nanoparticles dispersion on the graphene sheets. This greatly improves the electrocatalytic activities of Pt/graphene catalysts for methanol oxidation. In particular, the catalyst containing 7% of Al and Si exhibits the best electrocatalytic performance for methanol oxidation with mass activity of 1720 mA mg −1 . Therefore, Pt–AlOOH–SiO 2 /graphene hybrid is shown to be an effective catalyst for fuel cell application. [ABSTRACT FROM AUTHOR]