A. Chakradhar

Adsorption kinetics of benzene on graphene: An ultrahigh vacuum study

Experimental data for benzene adsorption on chemical vapor deposited graphene/Cu and graphene/SiO2 studied at ultrahigh vacuum conditions are discussed and compared with prior work on physical vapor deposited graphene/Ru(0001). Two widely considered topics, namely, the transparency of graphene and support effects of epitaxial graphene are investigated. Graphene is nearly transparent for benzene adsorption on both copper and silica supports opposed to Ru(0001). In addition, the desorption energy for benzene on epitaxial graphene depends on the reactivity of the support.

Effects of the support on the desorption kinetics of n-pentane from graphene: An ultrahigh vacuum adsorption study

Adsorption kinetics of n-pentane on physical vapor deposited graphene/Ru(0001), chemical vapor deposited (CVD) graphene/Cu, and CVD graphene/SiO2 was studied by thermal desorption spectroscopy. The adsorption kinetics was affected by the support with desorption energies increasing as graphene/SiO2 < graphene/Cu < graphene/Ru(0001).Adsorption kinetics of n-pentane on physical vapor deposited graphene/Ru(0001), chemical vapor deposited (CVD) graphene/Cu, and CVD graphene/SiO2 was studied by thermal desorption spectroscopy. The adsorption kinetics was affected by the support with desorption energies increasing as graphene/SiO2 < graphene/Cu < graphene/Ru(0001).

REACTIVITY AND MORPHOLOGY OF Ni, Mo, AND Ni–Mo OXIDE CLUSTERS SUPPORTED ON MCM-48 TOWARD THIOPHENE HYDRODESULPHURIZATION

In this paper, the morphology, chemical composition and reactivity of MCM-48 powders impregnated with Ni, Mo or both toward hydrodesulphurization (HDS) of thiophene were characterized. The reactivity of the catalyst was quantitatively compared with a standard industrial catalyst (from HaldorTopsoe, Denmark) and a novel WS2 nanotube-based catalysts (from R. Tenne, Israel). Morphology and chemical composition were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDX), and EDX elemental maps. Reactivity was determined in a gas-chromatograph based mini flow reactor using thiophene as a probe molecule. The sulfided MCM-48 supported Mo catalyst showed the largest HDS activity with turnover frequencies (TOF) about half as large as for the commercial system under the test conditions used here. Presulfiding did increase activity of all MCM-48 catalysts.