Bridging the structure gap: Chemistry of nanostructured surfaces at well-defined defects

Comparative study of CO adsorption on flat, stepped, and kinked Au surfaces using density functional theory

“…For Au(111), a p(2×2) structure was used along with other coverages ranging from 0.33 ML (1 CO per unit cell) to 1 ML(3 CO molecules per unit cell). CO molecules were adsorbed on several sites to find the preferred adsorption site in such a way that CO molecule sits perpendicular to the surface with carbon atom close to the surface as reported in number of experiments [7,22,23]. A Monkhorst-Pack k-point mesh of 4×4×1 was used for (100) and 5×5×1 was used for (111).…”

“…In this regard, the focus has been mostly on CO adsorption due to its importance in many industrial processes and to its relative simplicity, contributing to the understanding of catalytic reactions [4][5][6]. The CO adsorption on a variety of transition metal surfaces has been reported vastly in the literature both experimentally and theoretically [7,8]. The importance of identifications of 'active sites' based on adsorption, desorption and sticking coefficients is emphasized in many papers [1][2][3], as real catalysts are known to consist of small metal clusters of various micro-facets of different orientations containing defects like steps and kinks [9].…”

Oxygen interaction with the Pd(112) surface: From chemisorption to bulk oxide formation

“…As a step back in complexity as compared to nanoparticles, vicinal surfaces allow the investigation of step edges with well-defined adsorption geometry present in a high density on the surface. [7][8][9] The present study focuses on the interaction of oxygen with the Pd(112) surface to gain more insight into the stability of the (112) step geometry under oxygen exposure. In situ surface x-ray-diffraction (SXRD) measurements were performed at various oxygen pressures ranging from ultrahigh vacuum (UHV) to 5 mbars and temperatures between 523 and 673 K. Additional information was obtained by low-energy electron diffraction (LEED), scanning tunneling microscopy (STM) measurements, and high-resolution corelevel spectroscopy (HRCLS).…”

Mobility and Oxidation of Adsorbed CO on Shape-Controlled Pt Nanoparticles in Acidic Medium

“…Also, the diffusion can be 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 influenced by the lateral interaction present in the adsorbate layer. In fact, as examined for stepped Pt surfaces, CO adsorbs more strongly in under-coordinated sites than in terrace sites [39][40][41][42] , and the rate of CO filling on under-coordinated is higher as higher is the overall CO coverage. 35 The argument above can be employed, at least in part, to justify why the CO ads does behave like an immobile species during its oxidation.…”