Electrochemical Polymerization of Pyrrole Containing TEMPO Side Chain on Pt Electrode and Its Electrochemical Activity

Poly(4-(3-(pyrrol-1-yl)propionyloxy)-2,2,6,6-tetramethylpiperidin-1-yloxy) (PPy-TEMPO) electrode is prepared by electrochemical polymerization on Pt electrode in NaClO4-CH3CN solution. The electrocatalytic activity of PPy-TEMPO for benzyl alcohol in NaClO4-CH3CN solution is investigated by cyclic voltammetry and in situ FTIR. Results show that PPy-TEMPO electrode exhibits high electrocatalytic activity for benzyl alcohol oxidation in the presence of 2,6-lutidine as the base, as compared with the bare Pt electrode under the similar conditions. On the basis of in situ FTIR data, it shows that TEMPO is oxidized to its cation at the potential about 0.4 V, and benzyl alcohol is oxidized to benzaldehyde instead of benzoic acid. Further studies of preparative electrolysis experiments by constant current electrolysis are carried out to confirm the high conversion to benzaldehyde, and the results are in good agreement with those from in situ FTIR investigations.