Title : Metal based electrocatalysts on CeO2/carbon, Nb2O5/carbon and carbon: Synthesis, characterization and investigation of their electrocatalytic activities for both anodic and cathodic fuel cell reactions
Abstract:
A fuel cell is electrochemical cell that converts chemical energy into electrical energy without intermediate of mechanical links. Fuel cells are different from batteries in requiring a continuous source of fuel and oxygen (usually from air) to sustain the chemical reaction, so it is very important to select suitable catalysts for both oxidation of the fuel and reduction of oxygen. Nanoscale materials are very important in many industries. There are many various synthesis methods such adsorption, electroless deposition, galvanic displacement or microwave irradiation methods which let to fabricate nanomaterials. Nanoparticles-based catalysts are usually heterogeneous catalysts broken up into metal nanoparticles in order to speed up the catalytic process. Metal nanoparticles have a higher surface area so there is increased catalytic activity because more catalytic reactions can occur at the same time. Nanoparticle catalysts can also be easily separated and recycled with more retention of catalytic activity than their bulk counterparts.
In the present work, Pt, Au and Co nanoparticles deposited on the different surfaces such as CeO2/carbon, Nb2O5/carbon or carbon were fabricated using the rapid microwave heating and adsorption methods. The synthesized catalysts were examined by Transmission Electron Microscopy, X-ray Diffraction and Inductively Coupled Optical Emission Spectroscopy. The electrocatalytic activity of the Pt, Au and Co supported catalysts towards the oxidation of alcohols and reduction of oxygen was investigated by cyclic voltammetry, chrono-techniques and rotating disk electrode linear sweep voltammetry.
Metal nanoparticles of ca. 1-15 nm in size were successively deposited onto the surfaces of CeO2/carbon, Nb2O5/carbon and carbon. Metal nanoparticles were uniform and well dispersed on the mentioned surfaces.
It has been found, that the modified catalysts show enhanced electrocatalytic activities towards alcohols oxidation as well as oxygen reduction reactions in comparison with those at the bulk platinum or gold catalysts.
