Ethylene electro-oxidation

Smirnova NW, Petrii OA, Grzejdziak A. 1988. Effect of ad-atoms on the electro-oxidation of ethylene glycol and oxalic acid on platinized platinum. J Electroanal Chem 251 73-87. 

One example of the application of in situ FTIR to the study of the near-electrode region concerns the study of the electro-oxidation of ethylene glycol (EG) at a platinum electrode in base. This work clearly illustrates the relative ease with which the products of an electrochemical reaction can be detected and identified, and a mechanism deduced. 

The electrochemical oxidation of polyhydric alcohols, viz. ethylene glycol, glycerol, meso-erythritol, xilitol, on a platinum electrode show high reactivity in alkaline solutions of KOH and K2C03 [53]. This electro-oxidation shows structural effects, Pt(lll) being the most active orientation. This results from different adsorption interactions of glycerol with the crystal planes [59]. 

The electro-oxidation of organics and more specifically of alcohols and polyols is also possible on silver electrodes in the following activity sequence methanol < ethylene glycol < glycerol [64]. With a bulk silver electrode and with a silver-modified glassy carbon electrode, oxidations proceed only in the area of silver oxide formation. 

Although the Bonnemann method is very interesting by allowing to vary and to control easily the composition and the nanostructure of the catalyst and is adapted to the preparation of real fuel cell electrodes, it displays also some limitations. For example, bismuth-containing colloids could not be prepared with the Bonnemann method, and even in presence of platinum salts. Moreover, the presence of bismuth hinders the reduction of platinum salts [59], However, platinum-bismuth is a good catalyst for ethylene glycol electro-oxidation in alkaline medium [59-62], Moreover, colloid of tin alone could not be obtained, and the reaction was only possible by coreduction in the presence of a platinum salt. Then, other colloidal methods should be developed keeping in mind the necessity of a similar flexibility as that of the Bonnemann method. 

As an example, platinum-bismuth catalysts with different atomic ratios have been prepared by the water-in-oil method and tested for the ethylene glycol electro-oxidation in alkaline medium [59],... 

PtSn/C electrocatalysts with R Sn atomic ratios of 50 50 and 90 10 were prepared by alcohol-reduction process, using ethylene glycol as solvent and reducing agent, and by borohydride reduction. The electrocatalysts were characterized by EDX, XRD and cyclic voltammetry. The electro-oxidation of ethanol was studied by cyclic voltammetry using the thin porous coating technique. The electrocatalysts performance depends greatly on preparation procedures and R Sn atomic ratios. 

Electro-oxidation of Ethylene Glycol on Pt-Based Anodes... 

Oliveira Neto A, Linardi M, Spinace EV (2006) Electro-oxidation of ethylene glycol on PtSn/ C and PtSnNi/C electrocatalysts. Ionics 12 309-313... 

Photocatalytic decomposition of alcohol Electro-oxidation of hydrogen Electroreduction of oxygen Ammonia synthesis Carbon monoxide methanation Carbon monoxide methanation Carbon monoxide oxidation Propene hydrogenation Benzene hydrogenation Oxidation of ethylene Coal liquefaction Electroreduction of oxygen Dehydrogenation of butadiene... 

Matsuoka K, Iriyama Y, Abe T, Matsuoka M, Ogumi Z (2005) Electro-oxidation of methanol and ethylene glycol on platinum in alkaline solution poisoning effects and product analysis. Electrochim Acta 51(6) 1085-1090... 

Sun ZP, Zhang XG, Liang YY, Li HL (2009) A facile approach towards sulfonate functionalization of multi-walled carbon nanotubes as Pd catalyst support fOT ethylene glycol electro-oxidation. J Power Sources 191 366—370... 

Maxakato NW, Arendse CJ, Ozoemena KI (2009) Insights into the electro-oxidation of ethylene glycol at Pt/Ru nanocatalysts supported on MWCNTs adsorption-controlled electrode kinetics. Electrochem Commun 11 534-537... 

Again the electro-oxidation of alkenes, particularly the low-molecular-weight alkenes such as ethylene and propylene, have been evaluated as an alternative fuel for application in fuel cells. A major limitation appears to be the incomplete oxidation and subsequent poisoning of the catalysts. Aldehydes have been identified as an intermediate product. 

Earlier studies had indicated aldehyde and ketone formation in the oxidation of ethylene however, later work using mass spectro-graphic analysis and gas chromatography reported no products other than CO2 and water. The coulombic efficiency determinations for the anodic oxidation of other unsaturated hydrocarbons in acid solution indicate that CO2 is the main reaction product (cf. Table 17). For lower olefins, i.e., C2H4 and oxidation is complete. For larger compounds, other products are formed however, the primary product is CO2. A general equation for hydrocarbon electro-oxidation can thus be written as... 

Smirnova, N., Petrii, O. and Grzejdziak, A. (1988). Effect of Ad-atoms on the Electro-oxidation of Ethylene Glycol and Oxalic Acid on Platinized Platinum, J. Electroanal. Chem., 251, pp. 73-87. 

Yang, L., J. Chen, X. Wei, B. Liu, and K. Kuang. Ethylene diamine-grafted carbon nanotubes A promising catalyst support for methanol electro-oxidation. Electrochim. Acta 53, 2007 777-784. 

All the Pt-based catalysts described in acidic medium can be applied to ethanol electro-oxidation in alkaline medium, too. Nevertheless, Pd is a metal that has displayed good performance in basic medium, mainly due to its low tolerance to CO poisoning in the Pd-sites, thereby favoring the rapid oxidation of this molecule to CO2. Because the properties of Pd are similar to those of Pt, some literature works have been devoted to the substitution of Pt with Pd during the preparation of electrocatalysts. Shen and Xu [45-47] have studied the oxidation of alcohols such as methanol, ethanol, glycerol, and ethylene glycol on... 

Oliveira Neto et al. [28] have investigated a series of PtRu/C, PtSn/C, and PtSnRu/C catalysts prepared by the alcohol-reduction method using an ethylene glycol/water solution. Particle sizes in the order of 2.7nm were achieved for the PtSn/C composition, which displayed catalytic activity close to 8.0 A gpt . Spinace et al. [60] have used the same method for the production of PtSn/C, PtRh, and PtSnRh/C catalysts. Their results were similar to those described in [28], i.e., small particle size (2.0nm), and uniform particle distribution on the carbon support, which culminated in significant catalytic activity for ethanol electro-oxidation. 

DPP was initially developed for the preparation of thin films and was lafer adapted for the preparation of materials in the powder form. DPP consists of dissolving mefal salts in the presence of a hydroxyl acid (cifric acid) and a polyhydroxylic alcohol (ethylene glycol), to obtain a solution with good metal distribution consisting of a resin of the precursor metal. To obtain the catalyst, each metal is stoichiometrically mixed with carbon Vulcan XC-72 or any other support and fired at high temperatures e.g., 300°C-400°C. The major advantage of this route is the attainment of robusf catalysfs wifh experimental composition close to the nominal one. This method has been employed in the synthesis of a series of PtSn/C materials [19-21,27]. Nevertheless, proper control of particle morphology and metal distribution must be improved, in order to obtain better catalytic activity for ethanol electro-oxidation, which is currently under 1.0 A Spt ... 

Matsuoka, K., Iriyama, Y., Abe, T., Matsuoka, M. Ogumi, Z. (2005). Electro-oxidation of Methanol and Ethylene Glycol on Platinum in Alkaltne Solution Poisoning Effects and Product Analysis. Electrochimica Acta, Vol.51, N0.6, (November 2005), pp. 1085-1090, ISSN 00134686... 

PtSn/C electrocatalyts are claimed to be active electrocatalysts for ethanol electrooxidation and their performances depends greatly on the preparation procedure and Pt Sn atomic ratio. In this work, PtSn/C electrocatalysts with Pt Sn atomic ratios of 9 1, 3 1, 1 1 and 1 3 were prepared in water/ethylene glycol using electron beam irradiation. The obtained materials were characterized by EDX and XRD and tested for ethanol electro-oxidation in acid medium using chronoamperometiy. X-iay diffractograms of PtSn/C electrocatalysts showed typical face-centered cubic (fee) stractuie of Pt with average crystallite size of 2 nm and the presence of a Sn02 phase (cassiterite). PtSn/C electrocatalysts prepared with Pt Sn atomic ratios of 9 1 and 3 1 were more active for ethanol electro-oxidation than commercial PtSn/C BASF electrocatalyst. 

The interaction of poly(ethylene oxide) and other polar polymers with metal salts has been known for many years (Bailey and Koleska, 1976). Fenton, Parker and Wright (1973) reported that alkali metal salts form crystalline complexes with poly(ethylene oxide) and a few years later, Wright (1975) reported that these materials exhibit significant ionic conductivity. Armand, Chabagno and Duclot (1978, 1979) recognised the potential of these materials in electro-chemical devices and this prompted them to perform more detailed electrical characterisation. These reports kindled research on the fundamentals of ion transport in polymers and detailed studies of the applications of polymer-salt complexes in a wide variety of devices. 

The development of transparent polymer electrolyte membrane from the bi-continuous-microemulsion polymerization of 4-vinylbenzene sulfonic acid Hthium salt (VBSIi), acrylonitrile and a polymerizable non-ionic surfactant, co-methoxypoly(ethylene oxide)4o-undecyl-a-methacrylate (Ci-PEO-Cn-MA-40) was reported in 1999 [94,95]. The ionic conductivities of the polymer electro-... 

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