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Electrocatalytic oxidation of methanol on Pt modified polyaniline in alkaline medium

“…The CVs on Pt (solid lines) and Pt/PANI (dashed lines) in the three media have characteristic peaks of methanol oxidation in the anodic and cathodic scans similar to those observed in acid medium [7][8][9][10][11][12] but at much more favorable potentials. Leaving the specifics which have been discussed in detail in [7][8][9][10][11][12], the overall process of oxidation on Pt has been explained to proceed via the adsorption of methanol molecules on the Pt sites covered by OH − /OH − , CO 3 2− /OH − , HCO 3 − in the respective media in the anodic direction and produces maximum current at the peak potentials after which the currents decrease due to the passivation of the catalytic sites. The appearance of a pronounced anodic peak current in the cathodic potential scan is attributed to the high activity of the Pt particles which are now divested of the passive film formed in the anodic cycle [36].…”

“…These include the use of bimetallic catalysts such as Pt-Ru [4], Pt-WO 3 [5] and alloys of Ru-Pd [6] which reduce the overpotential for methanol oxidation considerably but are however not cost effective. Among the attempts to develop cost effective electrodes it has been shown that the dispersion of Pt in very minute quantities in the form of microparticles inside a polymer matrix, a process generally referred to as polymer electrode modification leads to a remarkable enhancement in the electrocatalytic activity for the oxidation of methanol [7][8][9], attributed essentially to (i) an increase in active surface area by dispersion of the catalyst and (ii) a better utilization of Pt crystallites in decreasing the poisoning effect of CO [10][11][12]. Such systems have not only been used for methanol oxidation but also for oxidation of other small organic molecules such as HCHO, HCOOH, ethylene glycol, d-glucose, etc.…”

“…The use of most of these systems have, however, been restricted to oxidation of methanol in acid medium [7][8][9][10][11][12][15][16][17] wherein the poisoning species strongly bind to the catalytic centers imposing limitation in the kinetics of the methanol oxidation leading to polarization losses. It was after Parsons and Van der Noot [2] suggestion of the possibility of using alkaline media for the organic fuel cell reactions that many studies have been oriented in this direction.…”

Phase diagrams of microemulsions containing reducing agents and metal salts as bases for the synthesis of metallic nanoparticles

“…This has proved to be a solution to the problem as it prevents the fast poisoning of the catalyst [1,[3][4][5][6][7][8][9][10]. Different mechanisms were suggested for the role of the added modifying element, namely (a) adsorption of the alcohol molecules on Pt and oxygen derivatives generated from the decomposition of water on the added element (for example Pb, Sn) [11][12][13], (b) "ligand effect" (electronic interaction of the added element with Pt which changes the adsorption energy of the adsorbate on Pt) [14], and (c) homogeneous catalytic reactions which was confirmed by the presence of complexed cations of the added element in the reaction media [12,15].…”

Electro‐Oxidation of Methanol and Ethanol on Poly(3,4‐Ethylenedioxythiophene) with Dispersed Pt, Pt + Sn, and Pt + Pb Particles

“…An increase in the catalytic activity of platinum after the additional introduction of small quantities of other metals, e.g., Sn or Pb [9 ± 11, 19 ± 25] was found. Investigations were performed by using CP such as poly(3-methylthiophene) (PMT) [22], and polyaniline (PANI) [23]. It was found that Pt crystallites maintain their activity for a longer period if a polyaniline (PANI) matrix is used as a support [23].…”