Electrocatalysis of the reduction of iron(III) by halides adsorbed at platinum electrodes in perchloric acid solutions

Pseudo-Single-Crystal Electrochemistry on Polycrystalline Electrodes: Visualizing Activity at Grains and Grain Boundaries on Platinum for the Fe2+/Fe3+ Redox Reaction

“…61 It has been suggested previously that sulfate, or other specifically adsorbed anions (such as Cl -and Br -), can facilitate Fe 2+ oxidation by acting as a bridge for electron transfer, or by modifying the electrical double layer. 62 Given that sulfate adsorption on platinum surfaces is facet sensitive, 63,64 one might expect that the activity for Fe 2+ oxidation could be affected accordingly. clearly evident that a correlation exists between structure and activity in sulfuric acid, but it is that the activity of the surface is strongly dominated by grain boundaries, with the grains themselves also having some lower activity.…”

Mapping the dynamics of reversible and irreversible heterogeneous electron transfers under steady-state conditions by the phase-space method

“…However, a value of 0.88 is obtained from P max  De red fwhm as expected from Eq. (26). In order to determine the degree of reversibility of ferric ion reduction, we have plotted P ðnÞ=n as a function of n (Fig.…”

“…The kinetics of the ferric-ferrous redox reaction in aqueous solution on solid electrodes is a matter of continuing interest because complications may arise due to the presence of complexes with ferric and/or ferrous ions in the presence of a ligand. It is well known that chloride, bromide, or sulfate influences the reaction rates [25,26]. A catalytic effect is observed because these anions adsorb on the metal electrode surface, and thereby reduce the electrostatic repulsion of iron ions from the electrode or provide a bridge for a faster electron transfer (inner-sphere catalysis) [27,28].…”

Electrochemistry of Fe3+/2+ at highly oriented pyrolytic graphite (HOPG) electrodes: kinetics, identification of major electroactive sites and time effects on the response

“…2,3,18 Here, we present a study of the Fe 3+/2+ redox couple in aqueous solution, which is known to have much slower ET kinetics, 30 but is still regarded as an outer-sphere process, 29 although one that can be promoted (enhanced) by some adsorbed anions at metals such as platinum. 31,32 Thus, with careful experimental design, this is a very attractive redox system with which to make kinetic comparisons on different electrodes.…”