The importance of adsorption in anodic surface‐catalyzed oxygen‐transfer reactions at gold electrodes

Abstract

A large number of anodic oxygen-transfer reactions were studied at Au electrodes in both acidic and alkaline media. Results o f competitive adsorption studies are interpreted and support the conclusion that adsorption is a prerequisite to subsequent oxygen-and electron-transfer steps. Many of these oxidation reactions gave the voltammetric appearance of reversible waves, even though the observed half-wave potential values were shifted hundreds o f millivolts positive of the thermodynamic potentials. A catalytic mechanism is proposed in which adsorbed hydroxyl radicals (AuOH) participate in the oxygen-transfer step. The absence of pH effects on half-wave potentials for several inorganic compounds suggests that the electron transfer precedes the deprotonation step for these reactants.

Pulsed amperometric detection waveform with disposable thin-film platinum working electrodes in high performance liquid chromatography

“…Au ca. +0.05 V [18]). Given that oxygen is always present in solutions and at fluctuating levels, analyte detection using platinum electrodes at +0.30 V (E1) is certain to be affected by oxygen-related interferences [4] giving rise to noise affecting chromatographic baselines.…”

The electrochemistry of gold–platinum alloys

“…11. that organic compounds are oxidised in the presence of AuOH formed in the pre-monolayer region [17].…”

The electrochemical oxidation of penicillins on gold electrodes

“…In Figure 6 , one can see that amoxicillin shows continued oxidation following the initiation of the negative potential scan (1450 mV). This means that the oxidation of amoxicillin is catalyzed in the presence of the higher oxide, as has previously been concluded for phenol [39]. Response throughout the rest of the CV is typical of penicillin behavior.…”

“…In the absence of surface oxide, the proposed electrocatalytic oxidation pathway would be unavailable. Despite the lack of any perceptible residual oxide formation, literature sources [39] report the presence of small amounts of The current response to increased penicillin G concentration is distinctly nonlinear; a linear extrapolation to larger concentration values will overestimate the current. Figure 2 shows this clearly at 1300 mV.…”