Networks of Steps on Au and Pt Crystals
نویسنده
چکیده
Networks of steps, seen in STM observations of vicinal surfaces on Au and Pt (110), are analyzed. A simple model is introduced for the calculation of the free energy of the networks as function of the slope parameters, valid at low step densities. It predicts that the networks are unstable, or at least metastable, against faceting and gives an equilibrium crystal shape with sharp edges either between the (110) facet and rounded regions or between two rounded regions. Experimental observations of the equilibrium shapes of Au or Pt crystals at sufficiently low temperatures, i.e. below the deconstruction temperature of the (110) facet, could check the validity of these predictions.
منابع مشابه
Interaction of atomic hydrogen with monometallic Au(100), Cu(100), Pt(100) surfaces and surface of bimetallic Au@Cu(100), Au@Pt(100) overlayer systems: The role of magnetism
The spin-polarized calculations in generalized gradient approximation density–functional theory (GGA–DFT) have been used to show how the existence of second metals can modify the atomic hydrogen adsorption on Au (100), Cu (100), and Pt (100) surfaces. The computed adsorption energies for the atomic hydrogen adsorbed at the surface coverage of 0.125 ML (monolayer) for the monometallic Au (100), ...
متن کاملGreen Approach to Synthesis of Pt and Bimetallic Au@Pt Nanoparticles Using Carica Papaya Leaf Extract and Their Characterization
This study reports a green approach to synthesis of monometallic platinum nanoparticles (Pt NPs) and bimetallic aurium@platinum nanoparticles (Au@Pt) using aqueous leaf extract of Carica papaya as a reducing and stabilizing agent. The nature and morphology of as-synthesized PtNPs and bimetallic Au@Pt NPs were characterized using UV/vis spectroscopy (UV–vis), high resolution transmission electro...
متن کاملA Selective Blocking Method To Control the Overgrowth of Pt on Au Nanorods
A method for the preparation of smooth deposits of Pt on Au nanorods is described, involving sequential deposition steps with selective blocking of surface sites that reduces Pt-on-Pt deposition. The Au-Pt nanorods prepared by this method have higher long-term stability than those prepared by standard Pt deposition. Electrochemical data show that the resulting structure has more extended region...
متن کاملHeteroepitaxial growth of Pt and Au thin films on MgO single crystals by bias-assisted sputtering.
The crystallographic orientation of a metal affects its surface energy and structure, and has profound implications for surface chemical reactions and interface engineering, which are important in areas ranging from optoelectronic device fabrication to catalysis. However, it can be very difficult and expensive to manufacture, orient, and cut single crystal metals along different crystallographi...
متن کاملStep Patterns on Vicinal Reconstructed Surfaces
Step patterns on vicinal (2× 1) reconstructed surfaces of noble metals Au(110) and Pt(110), miscut towards the (100) orientation, are investigated. The free energy of the reconstructed surface with a network of crossing opposite steps is calculated in the strong chirality regime when the steps cannot make overhangs. It is explained why the steps are not perpendicular to the direction of the mis...
متن کامل