Oxygen reduction reaction electrode preparation

Apparently, Holdcroft and Funt were the first to disperse platinum microparticles into a conducting film of PPy in order to activate the oxygen reduction reaction [59]. Different methods of preparation of the PPy/Pt electrodes were developed leading to film... 

Electrocatalytic Reduction of Oxygen. Oxygen reduction reaction (ORR) occurs on the cathode side of low temperature fuel cells and heavily loaded Pt/C is the most common electrocatalyst. Replacement of ORR catalysts with less expensive materials would have higher technical impact than for anode catalysts. Transition metals loaded carbides and carbide-metal codeposited carbon have been investigated for ORR application. For example, 40 wt% Pt/WC electrocatalyst prepared with RDE electrode showed a cathodic current (-5 x 10 A) similar to that of 40 wt% Pt/C with 0.5 M H2SO4, 100 mv/s and 2000 rpm (160). Also, 40 wt% Pt/WC exhibited electrochemical stability after 100 cycles of cyclic voltammetry from 0 to 1.4 V (vs RHE), whereas the cathodic current of 40 wt% Pt/C disappeared after 100 cycles. 

The oxygen reduction reaction on platinum is often studied using the rotating disc electrode as shown in Fig. 9.9a in the case of a Pt/C catalyst prepared by a... 

The electrocatalysis of the oxygen reduction reaction is of theoretical and practical interest because of its paramount importance for electrochemical energy conversion and industrial electrolysis. Au nanoparticles deposited on a BDD electrode show excellent activity towards catalytic reduction of oxygen [23], which also depends on the particle size, the nature of the support and the preparation method [24]. 

Girishkumar and co-workers have prepared Pt nanopartides through electrodeposition on optically transparent electrodes of SWNTs for both methanol oxidation and oxygen reduction reaction. These electrodes displayed greatly improved catalytic performances, and the methanol oxidation currents were about 10 times higher when the same amount of Pt nanopartides was supported on SWNTs. Moreover, the current values detected for oxygen reduction reactions were higher by a factor of 1.5 for Pt nanopartides supported on SWNT compared to unsupported Pt partides. ... 

The first reported electroorganic synthesis of a sizeable amount of material at a modified electrode, in 1982, was the reduction of 1,2-dihaloalkanes at p-nitrostyrene coated platinum electrodes to give alkenes. The preparation of stilbene was conducted on a 20 pmol scale with reported turnover numbers approaching 1 x 10. The idea of mediated electrochemistry has more frequently been pursued for inorganic electrode reactions, notably the reduction of oxygen which is of eminent importance for fuel cell cathodes Almost 20 contributions on oxygen reduction at modified... 

The electrocatalysts for oxygen reduction were prepared as follows. These complex compounds were inoculated onto the carbon (AG-3, BET area near 800 m2/g) by means of adsorption from dimethylformamide solutions. The portion of complex compound weighed so as to achieve 3% of Co content was mixed with the carbon, then 5 ml of dimethylformamide per 1 g of the carbon were added and the mixture was cured at room temperature for 24 hours. Series of samples obtained were thermally treated (pyrolyzed), and the resulting grafted carbons were tested as electrode materials in the reaction of molecular oxygen reduction. 

At IREQ, besides the participation in the field tests run by the engineers of Hydro-Quebec (12), the main effort has been to tackle fundamental problems in the field of electrocatalysis (18-22) and of anodic oxidation of different potential fuels (23-26). A careful and extensive study of the electrochemical properties of the tungsten bronze has been carried out (18-20) the reported activity of these materials in acid media for the oxygen reduction could not be reproduced and this claim by other workers has been traced back to some platinum impurities in the electrodes. Some novel techniques in the area of electrode preparation are also under study (21,22) the metallic deposition of certain metals on oriented graphite show some interesting catalytic features for the oxygen reduction and also for the oxygen evolution reaction. 

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