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Density functional theory calculations were performed to study the adsorption and dissociation of methane as well as syngas formation over Ni(111) and NiPt(111) aiming to gain insight into the effect of Ni(111) surface alloying on partial oxidation of methane (POM). Results show that Pt-doped Ni(111) surface is beneficial to the adsorption of CH x and H species while unfavorable to the desorption of H 2 . The process of CH → C + H is found to be the rate-limiting step of successive dehydrogenation of methane on NiPt(111). Especially, the processes of CH 4 → CH 3 + H and CH 3 → CH 2 + H proceed more easily on NiPt(111) than on Ni(111). Three potential pathways for CO formation in the POM process were proposed and calculations identified that CH + O → CHO → CO + H are likely to be the main routes for CO formation on Ni(111) with CH + O → CHO as the rate-limiting step. Further calculations reveal that the formation of CO and H 2 may be more difficult on NiPt(111) than on Ni(111). [ABSTRACT FROM AUTHOR]

Abstract: The effects of modification by HNO3 oxidization on the physico-chemical properties of activated carbon fiber (ACF), the adsorption of aniline, pyridine and phenol on ACF and modified ACF, as well as the influence of textural properties on adsorption by comparing ACF with an activated carbon are investigated. The adsorbents are characterized using N2 adsorption, Boehm titration, diffuse reflectance infrared Fourier transform spectroscopy, and temperature-programmed desorption. The pore properties of ACF are not significantly changed by the modification; however, it increases greatly the oxygenated acidic groups on the surface of ACF. The uptake for each aromatic compound by the modified ACF is lower than on ACF. This is mainly due to the decrease of dispersive interaction, more water cluster formed to block entry of compounds into micropores or competition between water and compounds adsorbed onto the surface of ACF because of hydrophilic increase of ACF. The maximum uptake for the aromatic compounds decreases with the increase in aqueous solubility of the adsorbates. K, a Langmuir parameter, is indirectly associated with the surface chemistry of ACF. For the aromatic compounds mentioned, the uptake increases with the micropore volume of carbon materials. [ABSTRACT FROM AUTHOR]