Catalytic oxygen reduction

Research on the direct conversion of chemical energy to electricity via fuel cells has received considerable attention in the past decades. Fuel cells are indeed attractive alternatives to combustion engines for electrical power generation in transportation applications and also as promising future power sources, especially for mobile and portable applications. Thus, the search for excellent electrocatalysts for the electro-catalytic oxygen reduction and methanol oxidation reactions, which are the two important cathodic and anodic reactions in fuel cells, is intensively pursued by scientists... 

The kinetic of catalytic oxygen reduction is closely connected with chemical condition of surface nanodispersed diamond. 

The studies of direct heterogeneous electron transfer have been carried out in most cases using cyclic and square wave voltammetry. In these studies the first of the two electrons required for the catalsftic reaction has been transferred although the authors do not see the shift of the reduction potential upon substrate addition as has been reported in Ref. [73] and is known for the reaction in solution. In all cases catalytic oxygen reduction is observed but only rarely could catalytic substrate conversion be achieved. 

For the fourth group of substance we could suggest mechanism with catalytic oxygen reduction via formation of intermediate complex similar by SOD (12). 

M. (2013) "Metal-free catalytic oxygen reduction reaction on heteroatom-doped graphene is caused by trace metal impurities. Angew. Chem. Int Ed., 52, 13818-13821. 

Some studies have shown that certain modification procedures can be used to transform two-electron reduction metalloN4-macrocyclic complexes into hybrid materials with the capability to reduce oxygen to water, either via the direct four-electron transfer pathway or in the series two-electron transfer pathway. Carbon nanomaterials, carbon nanotubes in particular [58-65], have been reported to significantly increase the catalytic oxygen reduction current, with a substantial reduction of the overpotential for ORR reported in some cases, as shown by the examples in Table 7.4. 

Liu L, Samjeske G, Takao S, Nagasawa K, Iwasawa Y (2014) Fabrication of PtCu and PtNiCu multi-nanorods with enhanced catalytic oxygen reduction activities. J Power Sources 253 1-8... 

The demineralised water transfer and storage system consists of the demineralised water storage tank, the demineralised water transfer pump, two catalytic oxygen reduction units and a condensate storage tank. The system has one contaimnent penetration, with isolation valves on either side. 

The catalytic performance of 1 was examined for hydroformylation of alkyne (as a catalyst additive) and methoxycarbonylation of alkyl halide, and 1 is also used as a stoichiometric reagent for an Ni-catalyzed ketone synthesis from alkyl halide. " Heterogeneous catalysts derived from 1 are used for hydrogenation of GO and coal tar pitch, crude oil upgrading, and coal liquefaction (preparation of the pyrrhotite catalyst). An Fe-Ru-Se catalyst dispersed on a glassy carbon-supported Nafion film prepared from 1 is reported to be effective for electro-catalytic oxygen reduction. ... 

Catalytic oxygen reduction reaction on Co-N sites ( = 2 or 4) of graphene in acidic and alkaline media was discussed [164]. The Co atom was coordinated in an SV-like site with two or four neighboring C-atoms substituted with N-atoms. The study stressed the importance of thermo dynamic corrections and solvation effects were accounted for. Co-N sites were found to be stable in the studied range of applied electric potential, while C0-N2 sites were stable only if the external potential U < 0.45 V. The computations confirmed dual-site 2 X 2 e oxygen reduction reaction pathway on C0-N4 sites. 

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