Search

Graphene and graphitic nanoribbons possess different types of carbon hybridizations exhibiting different chemical activity. In particular, the basal plane of the honeycomb lattice of nanoribbons consisting of sp2-hybridized carbon atoms is chemically inert. Interestingly, their bare edges could be more reactive as a result of the presence of extra unpaired electrons, and for multilayer graphene nanoribbons, the presence of terraces and ripples could introduce additional chemical activity. In this study, a remarkable irreversibility in adsorption of CO2 and H2O on graphitic nanoribbons was observed at ambient temperature, which is distinctly different from the behavior of nanoporous carbon and carbon blacks. We also noted that N2 molecules strongly interact with the basal planes at 77 K in comparison with edges. The irreversible adsorptions of both CO2 and H2O are due to the large number of sp3-hybridized carbon atoms located at the edges. The observed irreversible adsorptivity of the edge surfaces of graphitic nanoribbons for CO2 and H2O indicates a high potential in the fabrication of novel types of catalysts and highly selective gas sensors. [ABSTRACT FROM AUTHOR]

Abstract: Carbon black–silver hybrid catalysts were easily synthesized by a mixing method of acid-oxidized carbon black and the colloidal dispersion of silver nanoparticles. The silver colloidal dispersion was pre-synthesized by a chemical reduction of silver nitrate by dimethyl sulfoxide in the presence of trisodium citrate dihydrate as capping agents. In the mixing method, approx. 6.0 nm diameters of silver nanoparticles with face-centered cubic crystal structures are highly dispersed on the acid-oxidized carbon blacks due to the surface reactivity resulting from the enhancement of oxygen-containing functional groups. The hybrid catalysts were examined for electro-catalytic activity towards oxidation of hydrazine. The results clearly show that the carbon black–silver hybrid catalysts are highly active for electro-catalytic oxidation of hydrazine. [Copyright &y& Elsevier]