Stripping voltammetry of carbon monoxide oxidation on stepped platinum single-crystal electrodes in alkaline solution

On the behavior of CO oxidation on shape-controlled Pt nanoparticles in alkaline medium

“…In fact, the results obtained in Fig. 2 suggest that the CO electro-oxidation reaction on Pt nanoparticles in alkaline solution seems to be quite insensitive to the surface structure of the nanoparticles, in contrast with what would be expected from previous Pt single crystal studies [18][19][20]. Moreover, as previously reported by Chen et al [38] the CO stripping voltammetric profile obtained with a Pt thin film supported on Glassy Carbon (GC) in 0.1 M NaOH is almost identical to those obtained with the different Pt nanoparticles in the present work (Fig.…”

“…In fact, the only effect of the scan rate is the shift in the peaks' potential. Unlike the behavior observed for the stepped surfaces [18], there is not a significant change in the charge of each peak with the scan rate.…”

“…The CO stripping voltammogram in alkaline medium shows multiple oxidation peaks that can be correlated to the oxidation of CO on different surface sites, being even possible to assign each peak to the oxidation of CO with a specific surface site. Assuming that step sites act as center for nucleation of oxygen-containing species to catalyze CO oxidation, the existence of these multiple peaks has been related to differences in the CO surface diffusion rate between acidic and alkaline media [18], being the latter much slower that the former and also slower than the reaction rate [19]. For stepped and kinked Pt surfaces with (111) terraces and (110) or (100) steps, up to three different CO oxidation peaks located at 0.58, 0.70 and 0.78 V (vs RHE) have been observed and assigned to the CO electro-oxidation with kink/step sites and (111) terrace sites, respectively, [18].…”

“…Assuming that step sites act as center for nucleation of oxygen-containing species to catalyze CO oxidation, the existence of these multiple peaks has been related to differences in the CO surface diffusion rate between acidic and alkaline media [18], being the latter much slower that the former and also slower than the reaction rate [19]. For stepped and kinked Pt surfaces with (111) terraces and (110) or (100) steps, up to three different CO oxidation peaks located at 0.58, 0.70 and 0.78 V (vs RHE) have been observed and assigned to the CO electro-oxidation with kink/step sites and (111) terrace sites, respectively, [18]. Recently, a series of experiments have allowed reassigning the site release for a particular oxidation peak [20,21].…”

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

“…When the charge is delocalized at the one end of the molecule, the C-C bond becomes less shielded and is easier to break. Combining more facile C-C bond cleavage and the fact that CH x [52] and CO ads [76,77] can be adsorbed at lower potential in alkaline medium it could be deduced that selectivity towards C-C bond rapture pathway is enhanced.…”