Kinetics of electrocatalytic reduction of oxygen and hydrogen peroxide on dispersed gold nanoparticles

Abstract

The electrocatalytic properties of Au nanoparticles of mean size between 4.2 to 9.5 nm have been investigated for the oxygen reduction reaction (ORR). The particles were prepared on dispersed Vulcan XC-72R carbon black by reduction of a gold salt and by deposition of polymer stabilised gold sols. These were then attached to a glassy carbon disc electrode from their dispersion in a Nafion solution. The dependence on particle size of activity and selectivity for H(2)O(2) formation and the rate constants for oxygen and hydrogen peroxide reduction have been investigated using Rotating (Ring) Disc Electrode measurements. The electrocatalytic activity showed a maximum for a mean particle size of 5.7 nm and decreased significantly with particle size. The number of electrons exchanged per O(2) molecule increased from a value close to 2 to 3.4 as the potential was made more negative. The oxygen reduction selectivity for H(2)O(2) production was higher for mean particle sizes below 6 nm.

Trends in the Electrochemical Synthesis of H2O2: Enhancing Activity and Selectivity by Electrocatalytic Site Engineering

“…Notably, pure Ag has a high activity for this reaction, similar to that of Pt−Hg. All these materials are more active than Aubased catalysts, which have been extensively investigated in previous studies; 7,28,29 Pt−Hg, Ag, and Ag−Hg exhibit an order of magnitude improvement over Au, whereas the activity of Pd−Hg is 2 orders of magnitude higher.…”

“…(d) H 2 O 2 selectivity for different catalysts at 2.5 mAcm −2 of total current density. For this figure, data for Cu−Hg was extrapolated for ∼100 mV as it is unstable above 0.25 V. 27 Data for Au adapted from Jirkovsky et al, 28 data for Pt from Verdaguer-Casadevall et al, 48 and data for Pt−Hg from Siahrostami et al 20 All electrochemical experiments were performed at 50 mV s −1 and 1600 rpm in O 2 -saturated 0.1 M HClO 4 at room temperature with corrections for Ohmic drop. The surface area was normalized to the geometrical value.…”

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

“…[56] Furthermore, Jirkovský et al have observed particle-size effects in perchloric acid solution. [51] Thus, the effect of particle size on catalytic activity is evident in alkaline as well as in acidic media, but still remains a topic of interest. [57] Alexeyeva et al prepared AuNP/carbon-nanotube composite materials using different approaches and these catalysts showed high electrocatalytic ORR activity in acidic media.…”

“…Thus, AuNPs supported on high-area carbon materials such as carbon nanotubes or carbon black and, more recently, on graphene, have been used as electrocatalysts for O 2 reduction. [41][42][43][44][45][46][47][48][49][50][51][52][53][54] Tang et al investigated how Au particle size affects the ORR activity in a basic electrolyte. [41] They found that 3 nm Au clusters on a carbon support exhibited higher ORR activity, and also a four-electron reduction of O 2 occurred on these particles, whereas on 7 nm AuNPs the two-electron reduction to HO 2 À predominates.…”

Enhanced electrochemical reduction of hydrogen peroxide on silver paste electrodes modified with surfactant and salt

“…Recently, interest has been shown in using nanoparticles (especially nanoparticles of noble metals such as gold) [29][30][31] for the electro-analytical detection of hydrogen peroxide [2,13,32,33]. The microelectrode arrays created by the deposition of metallic nanoparticles on electrodes have been shown to significantly improve the sensitivity of electro-analytical sensing methods due to their large specific surface areas, excellent conductivities and biocompatibilities.…”