The oxidation of carbon monoxide was studied on a single-crystal Pd( 11 1) catalyst using an elevated pressure I R cell/ultrahigh vacuum surface analysis system. The reaction kinetics were followed a t elevated pressures by measuring the total pressure change during the course of reaction. In the temperature range of 500-570 K an apparent activation energy of 28.1 f 0.3 kcal/mol was determined,...

Green coconut fiber (Cocos nucifera L.) has been largely used in solid-phase extraction. The effect of the initial dye concentration (1.91, 3.02 and 4.02) × 10−5 mol∙L−1 and solid phase contact (SPE) time were evaluated at different temperatures (283, 298 and 313) K at pH 2. Kinetic experimental data were applied to three simplified kinetic models: pseudo-first order, pseudo-second order, and i...

Chemical modification of naturally occurring polysaccharide, guaran has been made by incorporating 5aminosalicylic hydroxamate moiety to improve its selectivity and capacity for heavy metal ions. 5Amino salicylic acid hydroxamate derivative of guaran (ASAH-G) was synthesized, characterized and its adsorption behavior with Fe(II), Co(II), Ni(II), Cu(II), Zn(II), Cd(II), U(VI), W(VI), Cr(VI) and ...

The adsorption isotherms of Fe(CO), on Nay, HY and Linde L zeolites obtained in McBain balances show micropore adsorption, whereas additional capillary condensation is found with zeolite omega and Na-mordenite. The pores and/or cages of the zeolites studied are completely filled with the complex upon saturation, with the exception of Na-mordenite. Their behaviour is explained, respectively, by ...

The surface properties of poly(methyl methacryl-ate-co-n-butyl methacrylate-co-cyclopentyl methacryloxy propyl-polyhedral oligomeric silsesquioxane) (poly(MMA-co -BMA-co-POSSMA)) were studied by means of inverse gas chromatography (IGC) using 10 non-polar and polar solvents as the probes. Thermodynamic parameters of adsorption, such as the dispersive component of the surface energy, the specifi...

The adsorption and dissociation of carbon dioxide on a Ru(0001) single crystal surface was investigated by reflection-absorption infrared spectroscopy (RAIRS) and temperature-programmed desorption (TPD) spectroscopy for CO2 adsorbed at 85 K. RAIRS spectroscopy shows that the adsorption of CO2 on a Ru(0001) single crystal is partially dissociative, resulting in CO2 and CO. The CO vibrational mod...

The electronic desorption of CO and its readsorption on \aluminum (natural oxide film) was studied and found to be influenced by the adsorption of H2. A theoretical model was developed which fits the experimental data and reliably predicts the adsorption-desorption characteristics at low electron energies (100 300 eV). At higher energies the picture is complicated by the release of subsurface g...

The local reactivity of thin pseudomorphic Pd overlayers on Au(111) and (100) single crystal surfaces has been studied by periodic density functional theory calculations within the generalized gradient approximation. We have determined the adsorption energies of atomic hydrogen and of CO as a microscopic probe of the reactivity. We demonstrate that both surface strain effects and substrate inte...

The oxidation of CO has attracted great interest in recent years because of its important role in enhancing the catalyst durability in fuel cells and in solving the growing environmental problems caused by CO emission. The usually used noble metal nanocatalysts are costly and require high reaction temperature for efficient operation. We report here a density functional theory (DFT) study of low...

The chemisorptive behavior of CO on Pd-Au alloy films has been studied by infrared reflection-adsorption spectroscopy (IRAS). Geometric (ensemble) and electronic (ligand) effects have been addressed by comparing the results with the corresponding single-component systems. A unique CO vibrational feature at 2088 cm-1 is associated with CO adsorption on isolated Pd sites. Considering the frequenc...