Electrochemical reduction of oxygen on nanostructured gold electrodes

Oxygen Electroreduction Catalyzed by Gold Nanoclusters: Strong Core Size Effects

“…Figure 3 A shows the rotatingdisk voltammograms of oxygen reduction recorded at the Au 11 /GC electrode in an oxygen-saturated 0.1m KOH solution at different rotation rates (from 225 to 3600 rpm). The current density plateaus are much better defined than those with larger Au nanoparticles; [13,29] overall, the voltammetric profiles are similar to those observed with Pt (or Pt-alloy)-based electrodes, [4] in which the current density increases with increasing rotation rates. The onset potential of oxygen reduction can be found to be approximately À0.1 V, which is close to that obtained from cyclic voltammetric measurements in Figure 2 (À0.08 V).…”

“…Notably, these values are all much higher than those with Au nanoparticles larger than 2 nm in diameter. [13,29] Second, with increasing Au cluster size, the onset potential of oxygen reduction shifts negatively: Au 11 /GC (À0.10 V) > Au 25 /GC (À0.16 V) > Au 55 /GC (À0.20 V) > Au 140 /GC (À0.25 V). Third, from linear regressions by the Koutecky-Levich equations (not shown), the electron-transfer kinetics of oxygen reduction also exhibit an apparent variation with gold cluster core size, as reflected by the apparent increase of kinetic limiting current density (J K ) with decreasing particle core dimensions, that is, at À0.5 V: Au 11 /GC (À17.9 mA cm À2 ) > Au 25 /GC (À10.0 mA cm À2 ) > Au 55 /GC (À9.3 mA cm À2 ) > Au 140 /GC (À1.7 mA cm À2 ).…”

Shape‐Dependent Electrocatalysis: Oxygen Reduction on Carbon‐Supported Gold Nanoparticles

“…Such behaviour is typical for O 2 reduction on nanostructured Au electrodes in acidic media. [29,30,44,46,52] A comparison of different Au catalysts is presented in Figure 7. It is important to note that for the nanoparticle-modified electrodes with a fixed mass of nanocatalyst per unit area, the electrocatalytic activity is determined by the size and shape of the catalyst particles.…”

“…[28] Sarapuu et al studied the electroreduction of O 2 on thin Au films prepared by vacuum evaporation and found that the specific activity (SA) does not depend on film thickness in H 2 SO 4 solution, but in KOH solution the SA decreases with film thickness. [29,30] Zeis et al have demonstrated the high electrocatalytic activity of nanoporous Au for the reduction of O 2 and H 2 O 2 . [31] Ohsaka and co-workers have carried out several studies on O 2 reduction on Au electrodeposited onto various substrates.…”

Electrocatalytic Reduction of Oxygen on a Pd Ad-Layer Modified Au(111) Electrode in Alkaline Solution

“…The reaction mechanism includes multi-electron reduction in aqueous solution proceeding in two overall pathways depending on electrode material and solution pH [1][2][3][4][5]. Bare electrode surfaces generally induce oxygen reduction via a twoelectron reduction process at two different potentials.…”