Electrocatalysts for Oxidating of Polyhydric and Monohydric Alcohols to Carbon Dioxide on Platinum Alloy Nanoparticles Dispersed on Noble Metal Oxides

The most important tasks in the previous century are to develop fuel cells as alternative electrochemical devices for efficient generation of energy. The low-temperature acid-type systems, such as hydrogen-oxygen polymer electrolyte membrane fuel cells and direct alcohol fuel cells are, at present, the most commonly studied devices in many laboratories world-wide [1-8]. Among organic compound fuels for anodic reactions in fuel cells, methanol has been historically most extensively studied and, more recently, alternative liquid fuels like a short chain alcohol (such as ethanol, ethylene glycol) becomes essential. It is well established that Pt is rated as the most active material for oxidation of small organic molecules in acidic media but the easily poisoning by intermediate byproduct – CO adsorb species the binary or ternary platinum-based alloys with Ru, Sn, Rh, Pb, Ir, W or Mo were proposed to enhance the electrooxidation activity towards alcohols[1-8]. The splitting of the C–C bonds is particularly difficult at ambient (low) temperatures, and the surface of catalytic platinum readily undergoes poisoning with intermediates of the ethylene glycol or ethanol oxidation. This problem may be partially solved by applying bifunctional electrocatalysts. Metals, like ruthenium, tin or rod may activate molecules of water and supply strong oxidizing agents: –OH groups and thus remove adsorbed species from platinum surface.

In order to increase the overall kinetic of electrooxidation of ethylene glycol or ethanol, we propose modification of bifunctional, metallic catalyst with metal oxide. Our concept involves adsorption onto the surface of commercial available Pt alloys nanoparticles ultra-thin layers of tungsten oxide, molybdenum oxide, zirconium oxide or iridium oxide. Presence of metals oxide (WO_3, MoO_3, ZrO₂, IrO₂) on nanoparticle have led not only to the specific interactions but also increased the catalytic surface. Introduction of noble metals oxide to Pt-based alloy nanoparticles lead to the increase of the catalytic current under voltammetric and chronoamperometric conditions.

 

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