Electrooxidation reaction

From the results obtained with in situ reflectance spectroscopy and on-line analytical methods, investigators at Universite de Poitiers proposed a complete mechanism for the electrooxidation of methanol at a platinum electrode. The first step of the electrooxidation reaction is the dissociative adsorption of methanol, leading to several species according to the following equations ... 

A substrate containing an amine carboxylate moiety is converted in an electrolyte solution in the presence of a strong acid to a cationic intermediate, an N-acyliminium cation, by electrooxidative reaction. This species is immediately reacted with an allylsilane [66, 67]. By nucleophilic reachon, C-C bond formahon is achieved. 

There have been even fewer studies of CO electro-oxidation on supported Au particles than on supported Pt. One may expect, however, on the basis of the studies on extended Au surfaces, that there will be a structure sensitivity to the CO electrooxidation reaction on supported Au particles. 

Employing potential-pH and cyclic voltammetric characterization techniques, Burke and coworkers [48, 73] have advanced the notion that incipient surface hydrous oxide species mediate the electrooxidation reactions of reducing agents of interest to electroless deposition. Thus, in the case of electroless Ni-B, an interfacial, basic, cationic Ni(I) hydrous oxide species would mediate the oxidation of DMAB, as shown in part here ... 

Liu and co-workers [160,172] reported a detailed computational study on the CO and CO/H2 electrooxidation reactions, in which they clarified the mechanistic role of the alloy metals in the promotion of electrocatalytic activity. First, they presented comparative DFT calculations of adsorption energies of CO, H2, and OH on surface slabs representing Pt(lll), a Ru(0001), a Pt monolayer on Ru... 

Electrochemical methods should be avoided because their chief electrooxidative reaction involving olefins is polymerization. 

Hence, the indirect path hides the NDR partly. These considerations strongly suggest that many of the electrooxidation reactions of organic molecules will fall into the class of HN-NDR systems, irrespectively of the detailed reaction mechanism. This presumption is supported by the fact that most of the reactions oscillate under gal-vanostatic control. 

ICA trimer films were produced by the electropolymerisation of 100 mM ICA in background electrolyte at + 1.46 V at the RDE, rotating at 4 Hz. Under these conditions [8,9], electrooxidation and film production occurs under steady-state current conditions at close to 100% current efficiency, and the film is expected to consist almost entirely of free trimer. The electrooxidation reaction was terminated after passing a charge of 173 mC. From equation (11.1) and (11.23) we calculate that this corresponds to 25 mC of redox charge or approximately 250 nmoles of deposited trimer. 

Hori and Murata [174], working at pH 6.8 in a phosphoric buffer electrolyte, proposed the electrooxidation of the protecting layer of the adsorbed CO to C02 followed by the electrooxidation of the Ni electrode. This was deduced from the values of the potential of the CO electrooxidation on the platinum and the rhodium electrodes and the standard equilibrium potential of the CO electrooxidation reaction. For solutions at pH values between 1 and 3 with sulfuric and perchloric electrolytes [175,176], it was proposed that the CO removal consisted of the stripping of an adsorption layer that includes the CO that was competitively adsorbed with water. This suggestion was because the Ni oxidation peak in the CO-containing acid solutions appeared only to be shifted in comparison with that in the pure acid solutions [167]. 

This current density is dependent on the distance, v, from the top to the bottom of the pores or from the top of the mountains to the bottom of the valleys at the rough surfaces. Therefore, we can consider that we have a mass-transport potential-dependent current density for an electrooxidation reaction ... 

The expression of the current density for an electrooxidation reaction under Tafel conditions in one-dimension is... 

Electrocatalyst for gaseous reactants [21-23] where the electrooxidation reaction arises from the gas as a reactant. For example, dissolved molecular hydrogen or carbon monoxide oxidation and the electroreduction of molecular oxygen or carbon dioxide. 

In what follows, we briefly review our density functional theory (DFT) calculations that investigate the mechanism of CO electrooxidation reaction. A commonly accepted mechanism for CO electrooxidation is the Langmuir-Hinshelwood mechanism, where oxygen-containing species, OH, formed on the Pt surface reacts with adsorbed CO to form CO2 [16, 34, 35]. In this model, OH is formed on the electrode surface by dissociative adsorption H2O. [26, 35] OH adsorption is assumed to be reversible and is given by the following two reactions ... 

Gasparotto LHS, Garcia AC, Gomes JF, Tremiliosi G (2012) Electrocatalytic performance of environmentally friendly synthesized gold nanoparticles towards the borohydride electrooxidation reaction. J Power Sources 218 73-78... 

Another method based on Fl-ECL inhibition method for determination of neurotransmitters, noradrenaline, and DA has been developed for Ru(bpy)3 /TPA and for Ru(phen)3 /TPA systems. The proposed inhibition mechanism shows the quenching effect of o-benzoquinone derivative generated from the direct electrooxidation reactions of noradrenaline and DA. This method has superiority of sensitivity over several detection methods, such as spectrometry, electro-chemical, CE, and HPLC methods, and has potential for sensitive and trace analyses of... 

Controlled electrochemical experiments are designed to probe select aspects of the formic acid electrooxidation reaction as a function of material selection and/or experimental conditions. Unfortunately, the selected experimental technique employed imposes deviations from a complex three-dimensional catalyst layer used in an operational DFAFC and thus results in inconsistencies between techniques. Assuming the current-potential relationship is always directly correlated to Faraday s law for charge and CO2 production, the assessment techniques can be broken down into three general categories (1) indirect correlation, (2) desorbed product detection, and (3) direct catalyst surface analysis. 

Fourier transform infrared spectroscopy (FTIR) is a powerful technique to probe real-time adsorbed surface species (reactants, intermediates, products) and solution constituents due to selected molecular dipole bond vibrations induced by tuned incident radiation [100]. FTIR has been used to study the formic acid electrooxidation reaction mechanism in situ by stepping or scanning the potential where species of interest are generated, from either high potentials where the intermediate species are completely oxidized (a clean surface, >1 V vs. RHE) or low potentials where the intermediate species approaches the coverage limit (blocked surface, <0.05 V vs. RHE) [100]. The three observed reaction intermediates for formic acid electrooxidation are linearly bonded COl, bridge-bonded COb, and bridge-bonded formate (HCOOad) with vibrational bands at 2,052-2,080 cm 1,810-1,850 cm , and 1,320 cm , respectively [27, 98]. The vibration frequencies of the adsorbates are influenced by the electronic characteristics and electrochemical potential of the electrode surface. Additional peaks of lesser intensity are observed for the water adlayer and sulfate/bisulfate at the electrode interface [27, 98]. 

Kazemi R, Kiani A (2012) Deposition of palladium submonolayer on nanoporous gold film and investigation of its performance for the methanol electrooxidation reaction. Int J Hydrogen Energy 37 4098 106... 

Electrocatalysis of formic acid (FA) oxidation reactions has been intensively studied for two main reasons (1) FA is an attractive chemical fuel for fuel cell applications due to its high energy density (1,740 Wh/kg, 2,086 Wh/L) and easy storage [1], and (2) FA is the smallest molecule that has four most common chemical bonds in organic compounds (C—H, C=0, C—O, O H), making FA an ideal model molecule for studying electrooxidation reactions. 

Giz MJ, Camara GA, Maia G (2009) The ethanol electrooxidation reaction at rough PtRu electrodeposits a FTIRS study. Electrochem Commun 11(8) 1586-1589... 

Lai SCS, Koper MTM (2010) The influence of surface structure on selectivity in the ethanol electrooxidation reaction on platinum. J Phys Orem Lett 1(7) 1122-1125... 

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