Electrocatalytic reduction of oxygen at ordered mesoporous carbon functionalized with tetrathiafulvalene

A novel ordered mesoporous carbon-tetrathiafulvalene composite is synthesized. It is based on host-guest chemistry which utilizes synergic interactions between a nanostructured matrix of ordered mesoporous carbon (OMC) and the excellent electron donor properties of tetrathiafulvalene (TTF). It has been found that some interesting properties of OMC are improved. Especially the density of the edge plane-like defective sites, important groups responsible for the electrocatalytic activity towards some molecules, is increased on OMC-TTF composite. Moreover, this new material can be used to facilitate the heterogeneous electron transfer process. OMC-TTF was used, for the first time, to investigate the electrocatalytic reduction of oxygen. The results show that the electrocatalytic behavior of OMC-TTF is attributed to the unique physico-chemical properties of OMC and TTF. At the OMC-TTF modified electrode, the reduction proceeds by the direct four-electron pathway whereas at the OMC electrode the process is not direct. In order to show that the ability of OMC-TTF to promote the electron transfer can allow the application of this composite in many domains, an amperometric oxygen biosensor has been constructed based on OMC-TTF. It exhibits good response to dissolved oxygen with a large linear range and a very low detection limit. The interferences of ascorbic acid and uric acid are suppressed and the applied potential is positive enough to avoid perturbations of other electrochemically reducible compounds. The results above suggest that OMC-TTF has potential applications in the detection of dissolved oxygen and interesting properties of this composite may open up a new approach to study the electrochemical behavior of other biomolecules.