The stability of hydrous oxide films on platinum

Abstract

The stability of hydrous oxide films grown on platinum in both acid and base was investigated as a function of holding potential in solutions of different pH. In contrast to similar films grown on gold -whose behaviour was described earlier -the stability of the bulk of the hydrous oxide deposks on platinum was not very dependent on solution pH. This was attributed to a rather facile rearrangement, in the case of platinum, of the initially anionic oxide species to a virtually neutral state. However, there was invariably a minor component in these deposits that was difficult to reduce in base; this probably involves an outer layer of oxide material (the latter being in contact 'with the aqueous phase) which retained its hyperextended, anionic form. Reduction of the bulk hydrous oxide in base showed a marked degree of inhibition in the region of 0 V(RHE); the effect seemed to be related to the presence of weakly bound hydrogen on the platinum surface. The hydrous oxide growth process on platinum showed a marked dependence on electrode history -this is a topic for further investigation.

Electrodeposition of Pt Nanoparticle Catalysts from H2Pt(OH)6 and Their Application in PEM Fuel Cells

“…The first and second sweep of the cyclic voltammograms shown in Figure were recorded from 0.68 to −0.25 V at 10 mV s –1 on FTO. The onset of cathodic current at approximately ∼0.50 V and subsequent reduction peak (P1) at 0.059 V was attributed to the reduction of H 2 [Pt(OH) 6 ] to Pt [reaction ], in agreement with the reduction peak for the [Pt(OH) 6 ] 2‑ /Pt 0 redox couple in acidic media. − …”

Investigating the Platinum Electrode Surface During Kolbe Electrolysis of Acetic Acid

“…In the work of Birss et al [37], the formation of an oxide layer of PtO(OH) 2 with Pt(OH) 3 HSO 4 was reported after polarization at high anodic potentials in a 0.5 M sulfuric acid solution. Burke and coworkers also showed that platinum oxide films were formed with different compositions after anodic polarization at high potential [40,41]. As such two different forms of platinum oxides are likely observed here.…”

An Investigation of Some Electrocatalytic Processes Occurring at Low Potentials at a Nickel Electrode in Base

“…Thus, hydrogen gas evolution on platinum in acid is a clear case where chemisorption of the intermediate is important; platinum hydrous oxide at low pH is quite unstable at low potentials (37) and is therefore not involved in this process. Thus, hydrogen gas evolution on platinum in acid is a clear case where chemisorption of the intermediate is important; platinum hydrous oxide at low pH is quite unstable at low potentials (37) and is therefore not involved in this process.…”

“…With regard to the different mechanisms of electrocatalysis, both approaches appear to be valid. Thus, hydrogen gas evolution on platinum in acid is a clear case where chemisorption of the intermediate is important; platinum hydrous oxide at low pH is quite unstable at low potentials (37) and is therefore not involved in this process. However, oxidation of various solution species, e.g., DMAB (25), formaldehyde (6), and hydrazine (7), on gold (a very poor chemisorber) in base seems to be a clear case where the incipient hydrous oxide approach is valid; the different onset potentials for oxidation of these compounds correlates quite well with premonolayer oxidation processes reported (6) for this electrode system.…”