Electrocatalysis thiols

The lure of new physical phenomena and new patterns of chemical reactivity has driven a tremendous surge in the study of nanoscale materials. This activity spans many areas of chemistry. In the specific field of electrochemistry, much of the activity has focused on several areas (a) electrocatalysis with nanoparticles (NPs) of metals supported on various substrates, for example, fuel-cell catalysts comprising Pt or Ag NPs supported on carbon [1,2], (b) the fundamental electrochemical behavior of NPs of noble metals, for example, quantized double-layer charging of thiol-capped Au NPs [3-5], (c) the electrochemical and photoelectrochemical behavior of semiconductor NPs [4, 6-8], and (d) biosensor applications of nanoparticles [9, 10]. These topics have received much attention, and relatively recent reviews of these areas are cited. Considerably less has been reported on the fundamental electrochemical behavior of electroactive NPs that do not fall within these categories. In particular, work is only beginning in the area of the electrochemistry of discrete, electroactive NPs. That is the topic of this review, which discusses the synthesis, interfacial immobilization and electrochemical behavior of electroactive NPs. The review is not intended to be an exhaustive treatment of the area, but rather to give a flavor of the types of systems that have been examined and the types of phenomena that can influence the electrochemical behavior of electroactive NPs. 

Kalimuthu et al. reported an electrochemical study of EbDH where the enzyme was immobilized on a 5-(4 -pyridinyl)-l,3,4-oxadiazole-2-thiol modified gold electrode and trapped under a membrane. No direct electrochemistry of EbDH was observed, but in the presence of ferrocenium methanol as an effective artificial electron acceptor mediated electrocatalysis of EbDH was demonstrated with its native substrate ethylbenzene (Figure 5.32A) and also the related substrate p-ethylphenol (Figure 5.32B). The catalytic system was modelled by electrochemical simulation across a range of sweep rates and concentrations of substrate and mediator. 

This chapter describes the development and use of modified electrodes with a focus on metaUoporphyrins and MPcs for electrocatalysis and electroanalysis of thiol oxidation. Firstly, the main preparation and characterization ways of MN4-modified electrode are presented, as well as the development of new immobilization strategies. The recent development of hybrid electrode materials combining MN4 macrocycles and nanoobjects are also described, with emphasis on their electrochemical properties. Finally, the main examples of development MN4-modified electrodes for the electroanalysis of thiols are commented. 

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