Oxygen Reduction on Polycrystalline Pt Electrode Modified by Acetonitrile in Neutral Electrolyte

Oxygen reduction was studied on pure polycrystalline PI electrode and on one modified by chemisorbed acetonitrile in neutral solutions containing sulphate or chloride anions. Measurements were performed on polycrystalline Pt rotating disc electrode by a potentiodynamic Sweep method

Ethanol Oxidation on Pd/Au(111) Bimetallic Surfaces in Alkaline Solution

Catalytic properties of Pd/Au(111) nanostructures obtained by spontaneous palladium deposition using PdSO4 and PdCl2 salts were examined for the oxidation of ethanol in alkaline media. Atomic force microscopy has shown that counter anions in Pd salts are responsible for the differences in surface topography. In both cases the oxidation of ethanol is characterized by the rise of a new peak at approximately the same potential for the same coverage, indicating similar electronic modification of Pd islands by the Au(111) substrate. Pd/Au(111) nanostructures obtained using PdCl2 salt have shown higher ethanol oxidation current densities, which can be ascribed to the surface structure consisting of thinner and smoother Pd deposit providing more convenient sites for the adsorption of ethanol and its subsequent oxidation

Minimum površinske hrapavosti: tanki sloj Ag deponovan na staklu

In this paper the results of an examination of the surface roughness and morphology dependence of silver thin films up to 100 nm thick deposited on a microscope glass on the deposition rate and on the deposition time are presented. It was found that, for a constant deposition rate, the surface roughness exhibits minimum at a certain layer thickness. This coincides with the turning point when the influence of the substrate surface on the deposition process becomes negligible, i.e., to the change in the nature of the system substrate/deposit from Ag/glass to Ag/Ag. For a constant layer thickness, the surface roughness minimum, achieved at a certain deposition rate, coincides to the turning point when the average free path for vertical adatom mobility becomes zero

STM analiza površine srebrnog ogledala

In this work, the structure of a silver mirror surface was examined by the STM technique. It was shown that the structural characteristics which enable a high degree of mirror reflection from this surface, which is very close to the ideal reflectivity of silver, are: flat and mutually parallel parts of the surface which are smooth on the atomic level, and distances between adjacent flat parts which state several atomic diameters.STM tehnikom je ispitana struktura površine srebrnog ogledala. Pokazano je da su strukturne karakteristike koje su omogućile visok stepen ogledalske refleksije koji je bio veoma blizak idealnoj refleksivnosti srebra: ravni i međusobno paralelni delovi površine koji su glatki na atomskom nivou, i rastojanja između susednih ravnih delova koja iznose nekoliko atomskih prečnika

Oxygen Reduction on Polycrystalline Pt and Au Electrodes in Perchloric Acid Solution in the Presence of Acetonitrile

Oxygen reduction reaction (ORR) was studied on polycrystalline Pt and Au electrodes in 0.1 M HClO(4) solutions containing various amounts of acetonitrile (AcN). The state of the electrode surface was characterized by cyclic voltammetry in oxygen free electrolytes, while ORR studies were performed on polycrystalline Pt and Au rotating disc electrodes by a linear sweep voltammetry in oxygen saturated electrolytes. Acetonitrile is chemisorbed on Pt over a wide potential range inhibiting both H adsorption and oxide formation. The extent of AcN chemisorption depends on its concentration in the solution. Initial potential of oxygen reduction is shifted negatively, while the kinetics of ORR is increasingly hindered with the increase of AcN concentration. Inhibiting effect of acetonitrile on ORR is pronounced on both Pt(poly) and Au(poly). Complete inhibition of ORR in the potential range of AcN chemisorptions is achieved for 0.1 M HClO(4) solution containing 1 M AcN on Au(poly) and 3 M AcN on Pt(poly)

Ethanol Oxidation on Pd/Au(111) Bimetallic Surfaces in Alkaline Solution

Catalytic properties of Pd/Au(111) nanostructures obtained by spontaneous palladium deposition using PdSO4 and PdCl2 salts were examined for the oxidation of ethanol in alkaline media. Atomic force microscopy has shown that counter anions in Pd salts are responsible for the differences in surface topography. In both cases the oxidation of ethanol is characterized by the rise of a new peak at approximately the same potential for the same coverage, indicating similar electronic modification of Pd islands by the Au(111) substrate. Pd/Au(111) nanostructures obtained using PdCl2 salt have shown higher ethanol oxidation current densities, which can be ascribed to the surface structure consisting of thinner and smoother Pd deposit providing more convenient sites for the adsorption of ethanol and its subsequent oxidation

Surface roughness of ultra-thin silver films sputter deposited on a glass

Silver was sputter deposited on a glass with a thin film thickness ranging from 10 to 80 nm. Scanning tunnelling microscopy was used to study the morphology of the obtained Ag-glass surfaces and to estimate the surface roughness. An equation for the surface roughness of the thin film was evaluated using parameters related to the thin film features: the surface roughness of the substrate, the compressibility of the thin film and the film thickness. The experimental results were fitted using the evaluated equation, and the conditions favouring lower or higher surface roughness were analyzed

Hydrogen evolution reaction on bimetallic Ir/Pt(poly) electrodes in alkaline solution

Hydrogen evolution reaction (HER) was studied in alkaline solution on Pt(poly) electrode modified by spontaneously deposited Ir nanoislands. Comprehensive insight into the characteristics of the bimetallic Ir/Pt(poly) catalysts was obtained by a combination of Atomic Force Microscopy (AFM), Field Emission Scanning Electron Microscopy (FESEM), X-ray Photoelectron Spectroscopy (XPS) and classical electrochemical techniques. HER investigations have shown that the presence of spontaneously deposited Ir enhances the activity of bare Pt(poly) in alkaline solution. This was attributed to the heterogeneity of the active surface sites and to the electronic interaction between two metals in close contact which together facilitated the adsorption of the H intermediate species.This is peer-reviewed version of the article: Svetlana Štrbac, Milutin Smiljanić, Thomas Wakelin, Jelena Potočnik, Zlatko Rakočević, Hydrogen evolution reaction on bimetallic Ir/Pt(poly) electrodes in alkaline solution, Electrochimica Acta (2019), [https://dx.doi.org/10.1016/j.electacta.2019.03.100][http://cer.ihtm.bg.ac.rs/handle/123456789/2951

Oxygen Reduction on Polycrystalline Pt Electrode Modified by Acetonitrile in Neutral Electrolyte

Oxygcn reduction was studied on pure polyclrystalline PI electrode and on one modified by chemisorbed acetonitrile in neutral solutions containing sulphate or chloride anions. Measurements were performed on polycrystalline Pt rotating disc electrode by a potentiodynamic Sweep method

Structural and electrical properties of tungsten - titanium sputtered coatings

Correlation of structural and electrical properties of W-Ti thin films deposited by sputtered were studies. The results have shown that changes of grain size are in agreement with the sheet resistance behavior as a function of the thin films thickness. The characteristic change of grain size and sheet resistance are obtained in thickness interval between 100 – 150 nmPhysical chemistry 2004 : 7th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 21-23 September 200