Electrooxidation of hydroquinone on simply prepared Au-Pt bimetallic nanoparticles

A facile method was used to prepare gold-platinum （Au-Pt） catalysts by direct electrodeposition via cyclic voltammetry in an acidic medium. Various parameters that affect the properties of electrodeposited catalysts were investigated such as initial ap- plied potential, scan rate and deposition time. Initial applied potential plays a more important role in the preparation of bime- tallic nanoparticles （AuPtNPs） since the kinetics of electrodeposition is in competition with the rate of hydrogen evolution. The AuPtNPs electrodeposited on pencil graphite （PG） were used to study the electrooxidation of hydroquinone. Various parame- ters such as pH, scan rate, concentration of hydroquinone and temperature were studied in the electrooxidation process. Ap- parent activation energy （Ea） for the electrooxidation of hydroquinone, calculated from the Arrhenius plot, shows that AuPtNPs catalysts （electrodeposited on the PG） offer less activation energy （ca. 9.500 kJ mo1-1） than the bare PG （ca. 10.345 kJ mol-1）. The AuPtNPs/PG shows better catalytic performance than the PG electrode due to the greater surface area it provides, thus re- sulting in more active sites available for adsorption of hydroquinone molecules on the surface of the catalyst.

Electrooxidation of ethylene glycol using gold nanoparticles electrodeposited on pencil graphite in alkaline medium

The electrooxidation of ethylene glycol(EG) on the surface of gold nanoparticles(AuNPs) in alkaline medium was investigated.AuNPs were electrodeposited on pencil graphite(PG) by fast scan cyclic voltammetry.Different sizes of AuNPs deposited on the surface of PG(AuNPs/PG) were used for the electrooxidation process.AuNPs were electrodeposited on PG at various deposition times in the same potential range but with different scan rates and scan cycles.Scanning electron microscopy(SEM),transmission electron microscopy(TEM) and X-ray diffraction(XRD) were used to visualize and characterize the prepared AuNPs/PG electrodes.Cyclic voltammograms were also used to investigate the electrooxidation of EG.The effects of EG and supporting electrolyte concentrations,scan rate,particle size of AuNPs and final potential limit on the electrooxidation process have been investigated.Further studies showed that the electrooxidation of EG is affected by temperature of the medium.The prepared AuNPs showed stability after long-term use.