Electrooxidation platinum adatoms

The use of adatoms of foreign metals obtained by imderpotential deposition on the platinum surface is another convenient method for investigating the effect of a promoter on the electrocatalytic properties of platinum. However, the effect of adatoms in this case has been shown to be not as effective for electrooxidation of methanol as for the oxidation of other organic molecules such as formic acid adatoms of tin, however, showed a positive effect on the rate of methanol oxidation. ... 

However, for some electrocatalytic reactions, such as the electrooxidation of alcohols, aldehydes or acides, and also the electro reduction of oxygen, lead adatoms can exhibit a promoting effect (3-7). Moreover, lead can change the selectivity in the case of electrocatalytic reductions of nitrocompounds (8), whereas it inhibits the adsorption of hydrogen on platinum (9,10),... 

The main aim of these studies is how to enhance the oxidation of glucose therefore, upd studies are also involved. As in the previous cases, the role of the crystalline surface structure of platinum electrodes in the electrooxidation is also studied. A series of studies was carried out by Wilde and Zhang using EQCM technique, in the presence and absence of adatoms in both acid and alkaline media. Unfortunately, owing to the very nature of the technique used, only phenomenological conclusions can be drawn from these latter studies and no information is furnished about the nature of the adsorbed species. The same refers to some other studies. ... 

Since around 1960, the formic acid electrooxidation mechanism has been investigated, resulting in several review articles [15-18]. Formic acid electrooxidation studies have been carried out on pure metal electrodes, such as platinum (Pt) [19], palladium (Pd) [20], gold [21-23], rhodium [24, 25], and iridium [26]. Studies have also been performed on alloys, intermetallics, and adatoms. The conversion efficiency is determined by the rate of a series of steps (a) reactant adsorption, (b) electrooxidation, and (c) product desorption. The electrooxidation... 

To improve the electrocatalytic activity of platinum and palladium, the ethanol oxidation on different metal adatom-modified, alloyed, and oxide-promoted Pt- and Pd-based electrocatalysts has been investigated in alkaline media. Firstly, El-Shafei et al. [76] studied the electrocatalytic effect of some metal adatoms (Pb, Tl, Cd) on ethanol oxidation at a Pt electrode in alkaline medium. All three metal adatoms, particularly Pb and Tl, improved the EOR activity of ft. More recently, Pt-Ni nanoparticles, deposited on carbon nanofiber (CNE) network by an electrochemical deposition method at various cycle numbers such as 40, 60, and 80, have been tested as catalysts for ethanol oxidadmi in alkaline medium [77]. The Pt-Ni alloying nature and Ni to ft atomic ratio increased with increasing of cycle number. The performance of PtNi80/CNF for the ethanol electrooxidation was better than that of the pure Pt40/CNF, PtNi40/CNF, and PtNi60/CNF. 

More recently, the influence of various factors like temperature, concentration, anions, adatoms (Bi, Cd, Tl, Pb, Re) was systematically reexamined in acidic and alkaline media . The complexity of the electrooxidation of glucose on platinum, mainly due to the hemiacetal group, was again evidenced. 

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