Promotion of palladium catalysis by silver for ethanol electro-oxidation in alkaline electrolyte

Preparation of PdAg and PdAu nanoparticle-loaded carbon black catalysts and their electrocatalytic activity for the glycerol oxidation reaction in alkaline medium

“…For PdAg(3:1)/CB and PdAg(1:1)/CB, the Pd3d doublets shifted to higher binding energies than Pd/CB, whereas the Ag3d doublets shifted to slightly lower binding energies than metallic Ag, 3d 5/2 (368.2 eV) and 3d 3/2 (374.2 eV). This is consistent with the results reported by Feng et al [23], who suggested that the Pd surface of the PdAg/C samples is electron-deficient because of the electron transfer from Pd to Ag. In principle, the binding energy shifts are caused by the initial and final state effects.…”

“…In the backward sweep, the fresh surface was recovered by the reduction of PdO and the residual poisoning intermediates were oxidatively removed again, leading to the appearance of the oxidation current. Almost no oxidation current would be visible in the backward sweep if the poisoning carbonaceous intermediates were completely removed in the forward sweep, so the ratio of peak current densities in the forward sweep (i f ) and backward sweep (i b ) is a measure of how clean the catalyst surface is or the tolerance to poisoning species [23]. For the Pd/CB electrode, the i b /i f ratio was evaluated to be 0.32.…”

In Situ Surface-Enhanced Raman Spectroscopy Study of the Electrocatalytic Effect of PtFe/C Nanocatalyst on Ethanol Electro-Oxidation in Alkaline Medium

“…Two behaviors were found: the first, in which the I f /I b rate was lower than unity (I f /I b < 1), indicated high adsorption and re-oxidation of carbonous species formed in the forward scan. A second behavior corresponding to a higher rate (I f /I b > 1) was related to more efficient ethanol oxidation as well as a lower accumulation of carbonaceous species into the catalysts [48,49]. In this sense, it is shown in Figure 7c that the synthetic method proposed herein enables Pt and PtFe nanomaterials with good tolerance to poisoning to be obtained.…”

“…This ability to remove by-products can be used as an indicator of the stability of nanocatalysts. In this manner, the stabilities of Pt/C and PtFe/C were tested by the following: (I) chronoamperometry; (II) comparing the peaks of the maximum current density as function of cycling; and (III) through evaluation of the poisoning tolerance to the adsorption of carbonaceous species by dividing the forward peak current density (I f ) by the backward peak current density (I b ) [47][48][49], with these results illustrated in Figure 7. Figure 7.…”

Rhodium Nanoparticle-Loaded Carbon Black Electrocatalyst for the Glycerol Oxidation Reaction in Alkaline Medium

“…The oxidation current in the backward sweep would scarcely appear if the poisoning carbonaceous intermediates were completely removed in the forward sweep, so the ratio of peak current densities in the forward sweep (i f ) and backward sweep (i b ) is a measure of how clean the catalyst surface is or how high the tolerance to poisoning species is [30]. The i b /i f ratios for the Rh/CB, Pt/CB, Pd/CB and Au/CB electrodes were evaluated to be 0.30, 0.42, 0.32 and 0.90, respectively.…”