A cyclic voltammetric study of the electrochemistry and chemical stability of the poly(vinylferrocene) (PVFc) redox couple, coated on a gold substrate, in aqueous solutions of H 2SO 4, HClO 4 and HCl was carried out. It was found that the anodic peak potential ( E pa) did not depend on the acid concentration in the range (1.0 × 10 −2 to 1.0 × 10 −7 mol L −1). However, the E pa values shifted linearly to less positive potentials when investigated in more concentrated acid solutions in the range 1–5 mol L −1. The slope of the E pa versus acid concentration graph was found to be in the order H 2SO 4 > HCl > HClO 4. In this regard PVFc behaved very similar to 1,1′-bis(11-mercaptoundecyl)ferrocene (Fc(C 11SH) 2) except for its chemical stability. In H 2SO 4 media the PVFc was found to be much less stable than 1,1′-Fc(C 11SH) 2. The dependence of E pa on acid concentration could be used to monitor state of charge of lead-acid batteries. However, for this application Fc(C 11SH) 2 would be a better choice because of its superior chemical stability.
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