Platinum

About: Platinum is a research topic. Over the lifetime, 49675 publications have been published within this topic receiving 1150035 citations. The topic is also known as: Pt & element 78.

Formation of intermediates during methanol oxidation : A quantitative DEMS study

Abstract: Current efficiencies for the formation of CO2 during methanol oxidation at smooth polycrystalline platinum electrodes were determined by differential electrochemical mass spectrometry in a thin layer flow through cell In all cases, the current efficiencies are below 60%; in particular, values as low as 16% were found in 01 M methanol solution at 06 V, which shows that a large amount of soluble intermediates (formaldehyde and/or formic acid) are formed The extent to which these soluble intermediates are further oxidized to CO2 depends on the diffusion conditions For methanol oxidation a parallel oxidation path via COad is also active The influence of the surface crystal structure and, in particular, of steps was also studied Step decoration by foreign metals allowed examination of the effect of cocatalytic metals on well defined model surfaces

Copper Oxide Nanoparticles: Synthesis, Characterization and Their Antibacterial Activity

Abstract: Copper oxide nanoparticles were prepared by electrochemical reduction method using tetra butyl ammonium bromide (TBAB) as structure directing agent in an organic medium viz. tetra hydro furan (THF) and acetonitrile (ACN) in 4:1 ratio by optimizing current density and molar concentration of the ligand. The reduction process takes place under inert atmosphere of nitrogen over a period of 2 h. Such nanoparticles are prepared using simple electrolysis cell in which the sacrificial anode as a commercially available copper metal sheet and platinum (inert) sheet act as a cathode. The parameters such as current density, solvent polarity, distance between electrodes, and concentration of stabilizers are used to control the size of nanoparticles. The synthesized copper oxide nanoparticles were characterized by using UV–Visible, FT-IR, XRD, SEM–EDS and TEM analysis techniques. The nanoparticles were tested for antibacterial activity against human pathogens like Escherichia coli (E. coli) and Staphylococcus strains and which was proved to be excellent.

Hydrogen peroxide electrochemistry on platinum: Towards understanding the oxygen reduction reaction mechanism

Abstract: Understanding the hydrogen peroxide electrochemistry on platinum can provide information about the oxygen reduction reaction mechanism, whether H(2)O(2) participates as an intermediate or not. The H(2)O(2) oxidation and reduction reaction on polycrystalline platinum is a diffusion-limited reaction in 0.1 M HClO(4). The applied potential determines the Pt surface state, which is then decisive for the direction of the reaction: when H(2)O(2) interacts with reduced surface sites it decomposes producing adsorbed OH species; when it interacts with oxidized Pt sites then H(2)O(2) is oxidized to O(2) by reducing the surface. Electronic structure calculations indicate that the activation energies of both processes are low at room temperature. The H(2)O(2) reduction and oxidation reactions can therefore be utilized for monitoring the potential-dependent oxidation of the platinum surface. In particular, the potential at which the hydrogen peroxide reduction and oxidation reactions are equally likely to occur reflects the intrinsic affinity of the platinum surface for oxygenated species. This potential can be experimentally determined as the crossing-point of linear potential sweeps in the positive direction for different rotation rates, hereby defined as the "ORR-corrected mixed potential" (c-MP).