The electrochemical precipitation on glassy carbon and gold electrodes of Ag(II) tetraphenylsulfonate porphyrin (Ag(II)TPPS) from aqueous HClO4 solutions, is reported. Electrochemical quartz crystal microbalance (EQCM) results indicate the possible formation of an Ag(II)-Ag(III) porphyrin dimer species. This species is oxidized and reduced in two consecutive steps: oxidation at +0.31 and +0.36 V (vs. SCE) and reduction at +0.11 and +0.07 V. The films show catalytic behavior toward O2 reduction in 10-2 M HClO4 at relatively low potentials (E < -0.1 V) but catalyze NO reduction at relatively high-reduction potentials (E < 0.4 V). The electrochemical results seem to indicate that the catalytic cycle in the case of NO involves formation of Ag(II)TPPS- Ag(II)TPPS(NO)+ and its electroreduction to regenerate Ag(II)TPPS-Ag(III)TPPS and NO-reduction products.
- O and NO reduction
- Silver tetraphenylsulfonate porphyrin
ASJC Scopus subject areas