Gold nanoparticles dispersed into poly(aminothiophenol) as a novel electrocatalyst—Fabrication of modified electrode and evaluation of electrocatalytic activities for dioxygen reduction

Gold nanoparticles were embedded into an electroactive polymer layer to modify the glassy carbon (GC) electrode and to fabricate a novel catalyst electrode. Cyclic voltammetry was performed to form the electroactive polymer, poly(aminothiophenol), PATP and deposit the Au0 nanoparticles, simultaneously. 4-Aminothiophenol (ATP) was converted into an inclusion complex with β-cyclodextrin and used to form the electroactive layer on the surface of GC electrode. Au0 nanoparticles were incorporated into film of PATP simultaneously by the electrolysis of a solution of HAuCl4. Thus, newer catalyst electrode, PATP-Aunano, was fabricated. The scanning probe microscopic image of PATP-Aunano indicates the presence of uniformly distributed Au0 nanoparticles of the sizes ∼10 nm. Electroactivity of PATP-Aunano for reduction of dioxygen (O2) was evaluated in O2 saturated solution. Cyclic voltammetry was used to demonstrate the enhanced electrocatalytic activity of the PATP-Aunano. A reduction peak at ∼430 mV with an enhanced peak current was observed for the oxygen reduction reaction (ORR) in O2 saturated 0.5 M sulfuric acid solution. A more positive onset potential and higher catalytic current for ORR are the striking features of PATP-Aunano catalyst. Double potential chronoamperometry, rotating disc (RDE) and rotating ring–disk electrode (RRDE) experiments were carried out to investigate the kinetic parameters of ORR on this electrode. Results from RDE and RRDE voltammetry experiments demonstrate that ORR on the PATP-Aunano is a four electron and diffusion controlled process with a catalytic rate constant of 3.65 × 103 M−1 s−1 and a diffusion coefficient of 7.82 × 10−5 cm2 s−1.

Gold nanoparticles were embedded into an electroactive polymer layer to modify the glassy carbon (GC) electrode and to fabricate a novel catalyst electrode. Cyclic voltammetry was performed to form poly(4-aminothiophenol), PATP and Au0 nanoparticles in the cyclic potential operation and to fabricate the newer catalyst electrode, PATP-Aunano. A more positive onset potential and higher catalytic current for oxygen reduction are striking features of the PATP-Aunano. The PATP-Aunano catalysts with different loadings of Au0 nanoparticles show promise for their use in fuel cells, O2 sensor, etc. Figure optionsDownload as PowerPoint slide