Homogeneous electrocatalysis

Among the plethora of solution phase, electrocatalytically active macrocycles for dioxygen reduction, only very few have been found to display no affinity for electrode surfaces. Attention in this Section will be mostly focused on the intrinsic electrochemical and electrocatalytic properties of two of such unique materials  

Intrinsic Properties of Solution Phase Transition Metal Macrocydes 

---

The macrocycles Co (111) (cyclam) and Fe( 111)TM PyP display high activity for dioxygen reduction and negligible affinity for carbonaceous surfaces providing close to ideal conditions to warrant analyses of electrochemical data within the strict homogeneous electrocatalysis framework. Their most salient features are summarized in the two sub-sections to follow. 

Homogeneous electrocatalysis in solution phase can be described via a regeneration mechanism where the catalyst reacts with the product of the electrode reaction involving the substrate to regenerate the initial electroactive species. This can be represented by the reaction sequence ... 

Electrochemical data recorded under no steady-state conditions can also be used for studying electrocatalytic processes involving porous materials. In cases where the catalytic system can be approached by homogeneous electrocatalysis in solution phase, variation of cyclic voltammetric profiles with potential scan rate (Nicholson and Shain, 1964) and/or, for instance, square-wave voltammetric responses with square-wave frequency (O Dea et al., 1981 O Dea and Osteryoung, 1993 Lovric, 2002) can be used. This situation can, in principle, be taken for highly porous materials where substrate transport, as well as charge-balancing ion transport, is allowed. On first examination, the catalytic process can be approached in the same manner... 

All-Union Scientific-Research Institute of Vitamins (VNIVI). Electrochemical group headed by Victor G. Mairanovsky (in Russian transcription Viktor Grigorievich Mairanovskii). Main directions mechanism of electroorganic reactions, homogeneous electrocatalysis, electrosynthesis in the chemistry of natural biologically active compounds incl. industrial processes (see Sect. 9.2). 

---