In situ FTIR studies of coadsorption of CN− and CO on Pt(1 1 0) electrode surface

The coadsorption of CN− and CO on Pt(1 1 0) electrode in acid solutions was investigated by using cyclic voltammetry and in situ FTIR spectroscopy. In comparison with individual adsorption of CO or CN−, the onset oxidation potential of CO (COad) coadsorbed with CN− is positively shifted ca. 100 mV, and its oxidation peak is postponed ca. 260 mV together with a significant decrease in current density. When the coadsorbed CO has been stripped completely, the CV recovers the feature of Pt(1 1 0)/CN− surface, which signifies that the coadsorption of CO does not affect the oxidation behavior of the coadsorbed CN− (CNad-). In comparison of CN− and CO adsorbed alone, the CNad- band is blue shifted from 2090 to 2108 cm−1 at 0.0 V, and the stark tuning rate is decreased dramatically from 53 to 4 cm−1 V−1; while the COad band is red shifted from 2075 to 2064 cm−1 at 0.0 V, and the stark tuning rate is slightly decreased from 24 to 19 cm−1 V−1, The result revealed the strong interaction between CNad- and COad at Pt(1 1 0) surface in the coadsorption system.

► CN− and CO coadsorption on Pt(1 1 0) was studied by in situ FTIR spectroscopy for the first time, and important results were reported.
► It has demonstrated that CN−ad has an inhibition effect for COad oxidation, while the anodic stripping of COad do not affect on previously adsorbed CN−.
► The results revealed the strong interaction between CN−ad and COad at Pt(1 1 0) surface in the coadsorption system.