Edge effects in an electrochemical reaction: HCOOH oxidation on a Pt ribbon

Abstract

The use of a ribbon-shaped Pt electrode gives rise to edge effects of the interfacial potential, as is predicted from the potential theory in the form of the corresponding reaction-migration equation. They are studied in the bistable region of formic acid oxidation. Essentially, the edges tend to be more passive than the bulk of the electrode, which also causes a passivation (activation) transition to originate from the edges (center) of the ribbon. The experimental results are in agreement with simulations of the reaction-migration system.

The Relationships among Hydrogen Adsorption, CO Stripping, and Selectivity of CO2 Reduction on Pd Nanoparticles

“…Accordingly, 0.35 M K 2 HPO 4 /KH 2 PO 4 was selected to be the electrolyte for the CO 2 ER in the RRDE study in order to reduce the current interference from the Pt oxidation in the electrolyte when the target species were oxidized in the same potential window of the Pt oxidation. [46][47][48][49][50][51][52][53] In this RRDE study, the currents on the Pt ring electrode were contributed by the intermediates and products generated on the disk electrode because the disk electrode potential was fixed at −0.2 V. These intermediates and products "in situ" generated at various electrolysis times could be detected by the Pt ring electrode when its potential was scanned positively. Therefore, all the species will start to be oxidized on the Pt ring electrode at their onset potentials when the electrode potential of the Pt ring is swept positively.…”

“…5a, which is attributable to the formate oxidation. 46,[50][51][52][53] Since a lot of formate species are generated on the disk electrode when the CO poisoning effect is minor (i.e., at short electrolysis times), the relatively high concentration of formate and the fast scan rate of LSV (50 mV s −1 ) may lead to the (minor) peak pattern (e.g., certain adsorbed formate may be formed and oxidized on the Pt ring electrode although the exact reasons are unclear). Moreover, on curves 2 and 3, the lower voltammetric currents at potentials > 0.8 V in comparison with those at potentials < 0.8 V may be due to the formation a monolayer of PtOH ads on Pt, losing its activity for the formate oxidation since the coverage of PtOH ads on Pt has been found to change the activity of Pt for methanol oxidation.…”

“…53 The peaks/shoulders at lines 2 and 3 were expected to be the oxidation of formate and CO, respectively. 46,[50][51][52][53] The large shoulder at 1.25 V vs RHE may be the oxidation of COOH * because for all C1 and C2 compounds produced by the CO 2 ER, only the formaldehyde and ethanol oxidations occur at such highly positive potentials, which should be impossibly produced on palladium at −0.2 V vs RHE. [47][48][49]52,53 Note that there was no peak or shoulder around this potential when there was no Pd/XC72 and no applied potential on the disk electrode (see curve 1), indicating that this shoulder was not attributable to the oxidation of electrolyte.…”

Understanding underlying processes in formic acid fuel cells

“…For example, electrochemical devices are conceivable where local activation of a poisoned electrocatalytic surface is sufficient to restore complete activity, if the interface can support the propagation of active fronts; the three-electrodes setup with the counter electrode sufficiently far away from the working electrode could be used in previous studies. 53,93,[97][98][99] However, there is no reference electrode in real fuel cells, and working and counter electrodes are often very close together in order to minimise ohmic losses in the electrolyte. In such cases, the coupling relevant for one electrode will not only depend on the potential distribution along itself, but also on the distribution at the other electrode.…”

Corrosion of Late- and Post-Transition Metals into Metal–Organic Chalcogenolates and Implications for Nanodevice Architectures

“…The metal chalcogenides are a diverse material class that includes the sulfides, selenides, and tellurides of metallic elements . This diverse material class includes high-mobility semiconductors (e.g., MoSe 2 ), superconductors (FeSe), superionic conductors (Ag 2 S), and topological insulators (HgTe). , In particular, low-dimensional semiconductor phases of these materials have drawn considerable interest because of the emergence of new properties when these compounds are reduced in size to few- or single-layer materials and are finding optoelectronic − and catalytic applications. ,− Hybrid coordination polymers have emerged as an alternate family of well-defined low-dimensional nanostructures in both the hybrid chalcogenolate − and hybrid perovskite material classes. − The organic side groups common to these compounds impart an additional dimension of chemical functionality and versatility. , In hybrid solids, one- (1D) or two-dimensional (2D) inorganic phases can be paired with ligands to form three-dimensional, crystalline supramolecular assemblies. In crystalline hybrid materials like MOChas, the organic constituent can be tailored to impact both the dimensionality and optoelectronic properties of the inorganic phase through ligand selection, forming ensemble nanostructures with well-defined chemical functionality and structure.…”