Determining the Active Surface Area for Various Platinum Electrodes

Abstract

Various methods, i.e., the adsorption/stripping of adsorbed probe species, such as hydrogen (H), copper (Cu), and carbon monoxide (CO), oxygen and hydroxide (O/ OH), potentiostatic CO/H displacement as well as double layer capacitance are exploited to evaluate the electrochemically active surface areas (ECAs) of platinum (Pt) foils, chemically deposited Pt thin film, and carbon-supported Pt nanoparticle electrodes. For the relatively smooth Pt electrodes (roughness factor < 3), the measurements from the stripping of H, Cu, and CO adlayers and CO/H displacement at 0.08 V (vs. RHE) give similar ECAs. With the increase of the surface roughness, it was found that the ECAs deduced from the different methods have the order of CO/H displacement less than the stripping of under potential deposition (UPD) Cu monolayer less than the stripping of the UPD-H adlayer. Possible origins for the discrepancies as well as the applicability of all the abovementioned methods for determining ECAs of various Pt electrodes are discussed, and the UPD-Cu method is found to be the most appropriate technique for the determination of ECAs of Pt electrodes with high roughness factors or composed of nanoparticles with high dispersion.

The correlation of electrochemical and fuel cell results for alcohol oxidation in acidic and alkaline media

“…Carbon monoxide (CO) can be used for this purpose because it is a strong adsorbent which also displaces other adsorbed species from the surface site and therefore can be used for the EASA determination as well as cleaning the electrode surface [19][20][21]. Firstly, the electrolyte is saturated with CO gas which is rapidly adsorbed on the Pt surface.…”

Electrochemical growth of platinum nanostructures for enhanced ethanol oxidation

“…3). The EASA has been determined [42] from the hydrogen adsorption and desorption charge after stabilization (10 cycles). Table 1 shows that even the samples treated with the shorter wave period (6 min) the EASA is enhanced by a factor 2.45.…”

“…The electrochemically active surface area (EASA) of this electrode was determined by integration of the charge in the hydrogen region of the cyclic voltammograms (CVs) between 0.05 and 0.4 V in 0.5 M H 2 SO 4 solution [42]. The activity for ethanol oxidation was investigated in 2 M ethanol + 2 M KOH by cyclic voltammetry between 0.05 and 0.70 V. All of the CVs were repeated until curves were obtained with high stabilization.…”

Sonochemical synthesis of graphene oxide supported Pt–Pd alloy nanocrystals as efficient electrocatalysts for methanol oxidation

“…The scan rate chosen for these measurements (10 mV/s) is appropriate according to the work of Chaparro et al [46]. In a recent study [47], it was concluded that, if a negative potential limit for integration equal to 0.05 V RHE is chosen, a charge of 0.22 mC would correspond to 1 cm 2 of Pt electrochemically active area. In our case, a potential of 0.05 V RHE corresponds to a potential of −0.17 V versus Ag/AgCl, which was chosen as the negative limit for voltammogram integration.…”