Electrochemical analysis of the kinetics and mechanism of the oxygen reduction reaction on Au nanoparticles

Impact of Cu-Pt nanotubes with a high degree of alloying on electro-catalytic activity toward oxygen reduction reaction

“…Electrochemical impedance spectroscopy (EIS) may be considered as one of the most sensitive tools for the study of the effects on the alloy composition of the Cu-Pt nanotubes on the kinetics of the ORR [21]. At a given potential (0.5 V vs. SCE), the electrochemical impedance spectra of the synthesized Cu-Pt alloys and the commercial Pt/C catalyst were further conducted in O 2 -saturated, 0.1 M HClO 4 solution with frequencies varied from 1.0 Â 10 5 to 0.01 Hz.…”

“…7(b), R ct represents the charge transfer resistance; R s is the solution resistance; CPE is the constant phase element that improves the quality of the fit. The impedance of CPE is defined as Z = 1/(jv) n Q), where j is associated with the complex number; v is the angular frequency (v=2pÁf); Q is related to the capacitance of the double layer (C dl ); n compensates the non-homogeneity due to the roughness of the electrode [21]. Moreover, since the roughness of the electrode may cause a variation of the effective solution resistant along the electrodes, the average C dl can be estimated from the obtained constant phase element (CPE) by using Eq.…”

“…Moreover, since the roughness of the electrode may cause a variation of the effective solution resistant along the electrodes, the average C dl can be estimated from the obtained constant phase element (CPE) by using Eq. (6) [21]: Table 3 presented the parameters of the equivalent circuit by using Zview software. Based on these parameters in Table 3 the exchange current density (i 0 ) is given by the following formula [24]:…”

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.…”

“…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.…”