High energy resolution fluorescence detection (HERFD) X-ray adsorption spectroscopy (XAS) is demonstrated as a new tool to identify the geometry of metal adsorption sites and the orbitals involved in bonding. The type of CO adsorption site on a nanoparticular Pt-Al2O3 catalyst is determined. The orbitals involved in the Pt – CO bonding are identified using theoretical FEFF8.0 calculations. In s...

The Lewis acidity of isolated framework metal sites in Beta zeolites was characterized with 15N isotopically labeled pyridine adsorption coupled with magic-angle spinning nuclear magnetic resonance (MAS NMR) spectroscopy. The 15N chemical shift of adsorbed pyridine was found to scale with the acid character of both Lewis (Ti, Hf, Zr, Nb, Ta, and Sn) and Brønsted (B, Ga, and Al) acidic heteroato...

We have investigated the performance of popular density functionals that include van der Waals interactions for the experimentally well-characterized problem of ethene (C(2)H(4)) adsorbed on the low-index surfaces of copper. This set of functionals does not only include three van der Waals density functionals-vdwDF-PBE, vdwDF-revPBE and optB86b-vdwDF-and two dispersion-corrected functionals-Gri...

The Layer-by-layer deposition of positively and negatively charged macromolecular species is an ideal method for constructing thin films incorporating biological molecules. We investigate the adsorption of fibronectin onto polyelectrolyte multilayer (PEM) films using optical waveguide lightmode spectroscopy (OWLS) and atomic force microscopy (AFM). PEM films are formed by adsorption onto Si(Ti)...

We have carried out first-principles calculations of H adsorption on Pd 211 using density-functional theory with the generalized gradient approximation in the plane-wave basis to find out that the most preferred is the threefold hollow site on the terrace of Pd 211 with an adsorption energy of 0.52 eV: the hcp and fcc sites being almost energetically equally favorable. For subsurface H adsorpti...

abstract phosphate is an essential element for plants, animals, and human. mobility and availability of phosphate in the natural systems is controlled by the adsorption-desorption and dissolution-precipitation reactions. iron (hydr)oxides including goethite play an important role in phosphate adsorption reactions in soil. surface area, crystallinity, and morphology of iron (hydr)oxides are the ...

We employ spin-polarized periodic density functional theory (DFT) to characterize CO adsorption and dissociation on the Fe(110) surface. We investigate the site preference for CO on Fe(110) at hCO = 0.25 and 0.5 monolayer (ML), for different functional forms of the generalized gradient approximation (GGA) to electron exchange and correlation within DFT. At 0.25 ML, we predict the existence of a...

The modified triangular-well potential model was applied to incorporate the effect of surface energy on the adsorption of particles or proteins on energetically heterogeneous surfaces. The method is convenient in simulating the adsorption on heterogeneous surface of which different region possesses different free energy. Spherical particles with attractive forces were added on the surface and u...

Fluorescence microscopy and intensity histogram analysis techniques were used to monitor spatially-resolved albumin adsorption kinetics to model heterogeneous surfaces on sub-μm scales. Several distinct protein subpopulations were resolved, each represented by a normal distribution of adsorption densities on the adsorbent surface. Histogram analyses provided dynamic information of mean adsorpti...

The interaction of H with Pd surfaces has served as a model system in surface science. We review theoretical aspects of the adsorption and absorption phenomena that have been studied in this system. Issues such as the site dependence of atomic adsorption energies, lateral interactions between adsorbates, adsorption on stepped surfaces, poisoning of surface reactions, adsorbate induced reconstru...