Glassy carbon tubular electrodes for the reduction of oxygen to hydrogen peroxide.

The oxygen reduction reaction (ORR) to produce hydrogen peroxide (H2O2) is of great industrial interest. Herein, a hydrodynamic electrochemical method is explored for use as a continuous method to produce H2O2 at the point-of-use. The ORR was studied in a tubular glassy carbon flow cell under a laminar flow regime.

Exploring the biochemistry at the extracellular redox frontier of bacterial mineral Fe(III) respiration.

Many species of the bacterial Shewanella genus are notable for their ability to respire in anoxic environments utilizing insoluble minerals of Fe(III) and Mn(IV) as extracellular electron acceptors. In Shewanella oneidensis, the process is dependent on the decahaem electron-transport proteins that lie at the extracellular face of the outer membrane where they can contact the insoluble mineral substrates. These extracellular proteins are charged with electrons provided by an inter-membrane electron-transfer pathway that links the extracellular face of the outer membrane with the inner cytoplasmic membrane and thereby intracellular electron sources.

The theory of cyclic voltammetry of electrochemically heterogeneous surfaces: comparison of different models for surface geometry and applications to highly ordered pyrolytic graphite.

The cyclic voltammetry at electrodes composed of multiple electroactive materials, where zones of one highly active material are distributed over a substrate of a second, less active material, is investigated by simulation. The two materials are assumed to differ in terms of their electrochemical rate constants towards any given redox couple. For a one-electron oxidation or reduction, the effect on voltammetry of the size and relative surface coverages of the zones as well as the rate constant of the slower zone are considered for systems where it is much slower than the rate constant of the faster zones.

Electrolyte tuning of electrode potentials: the one electron vs. two electron reduction of anthraquinone-2-sulfonate in aqueous media.

The electrode potentials of quinone redox centres in aqueous solutions can be tuned by varying the electrolyte cation identity. The phenomenon is due to the ion pairing effect of the tetra-n-butylammonium cation with the semiquinone intermediate species.

Semiquinone intermediates in the two-electron reduction of quinones in aqueous media and their exceptionally high reactivity towards oxygen reduction.

We report the catalytic anthraquinone-mediated reduction of oxygen at a boron-doped diamond electrode. Scheme of squares modelling confirms the existence of and reveals the role of the semiquinone intermediates, which are shown to have an exceptional reactivity towards oxygen (as compared to the di-reduced anthraquinone).