ELECTROCHEMICAL-BEHAVIOR OF OXOCARBONS ON SINGLE-CRYSTAL PLATINUM-ELECTRODES .2. CROCONIC ACID OXIDATION ON PT(S)-[N(100)X(111)] SURFACES IN 0.5 M SULFURIC-ACID MEDIUM
Jm. Orts et al., ELECTROCHEMICAL-BEHAVIOR OF OXOCARBONS ON SINGLE-CRYSTAL PLATINUM-ELECTRODES .2. CROCONIC ACID OXIDATION ON PT(S)-[N(100)X(111)] SURFACES IN 0.5 M SULFURIC-ACID MEDIUM, Journal of electroanalytical chemistry [1992], 376(1-2), 1994, pp. 101-108
The electrochemical behaviour of croconic acid at platinum single crys
tal electrodes with Pt(100) and Pt(2n-1,1,1) orientations has been stu
died in 0.5 M H2SO4 by cyclic voltammetry. Experiments with croconic a
cid in solution show two main processes: the oxidation of surface pois
ons at around O.8 V, and the oxidation of the acid, between 0.9 and 1.
25 V. While the currents involved in the first process tend to increas
e with the terrace width, the process at higher potentials gives maxim
um current density for short terraces (3-6 atoms width). Adsorption ex
periments have shown that, although strongly adsorbed species are form
ed from croconic acid even under open circuit conditions, the applicat
ion of a polarization significantly increases the amount of poison for
med. For each surface, maximum amounts of irreversibly adsorbed specie
s are formed at potentials around 0.4-0.5 V. The greatest amount of st
rongly adsorbed species is obtained with the Pt (100) electrode, for w
hich adsorbed CO seems to be the only adsorbate. For stepped surfaces,
some other intermediates may also be formed.