Electrochromic, Capacitive, and Electrocatalytic Performance of TEMPO Anchored EDOT-SN(T)S-EDOT Electrode

Conjugated polymers bearing TEMPO units are successfully used as catalysts for the selective oxidation of primary alcohols. Moreover, such polymers should exhibit satisfactory capacitive properties for energy storage applications. Herein, a TEMPO-substituted EDOT-SNS-EDOT conjugated unit was electropolymerized, and the resulting polymer film was investigated for its electrochromic, capacitive, and electrocatalytic properties. The donor structure of the monomer facilitated efficient polymerization. The polymer film displayed brownish-pink and blue-gray colors in its neutral and oxidized states, respectively, while its semioxidized states showed brownish and khaki hues. The optical contrast was determined to be 28% at 505 nm, with oxidation and reduction times of 1.20 and 1.38 s, respectively. The areal-specific capacitance of the polymer electrode was calculated as 3.81 mF/cm² (0.1 mA/cm²), ranking it at a high-mid level compared to other electrodeposited conjugated polymers reported in the literature. The electrocatalytic activity of the polymer film was evaluated using cyclic voltammetry (CV) in the presence of benzyl alcohol. The TEMPO units effectively catalyzed the oxidation of benzyl alcohol to benzaldehyde in the presence of 2,6-lutidine. Notably, the same polymer film was reused for three successive experiments without any loss of electrocatalytic activity. These findings demonstrate that the developed polymer film exhibits promising electrochromic, capacitive, and electrocatalytic properties.