Development of electrocatalytic hybrid film based on conducting polypyrrole–heteropolyanion

Abstract

The investigation focused on integrating heteropolyanions (HPAs) into a polymeric matrix of polypyrrole (PPy), aiming to achieve effective immobilisation for potential electrocatalytic applications. Specifically, the successful immobilization of a Dawson-type mixed addenda HPA, α2 – K8[P2W17V4+O62].10H2O, within conductive PPy films was achieved. These [P2W17V4+O62]-doped PPy films exhibited robust stability at both pH 2 and pH 7 during continuous potential cycling involving the V5+/4+ redox process. However, it was noted that in the negative potential range leading to polymer backbone reduction, the HPA tended to leach out from the film. In terms of catalytic assessments, the [P2W17V4+O62]-dopped PPy films displayed noteworthy electrocatalytic performance in the oxidation of ascorbic acid. Notably, they demonstrated a sensitivity of 8.18 (+/-0.15) μA mM−1 and a limit of detection (LOD) of 1.65 mM at pH 2.0. Furthermore, under neutral conditions, the films exhibited a sensitivity of 6.97 (+/-0.30) μA mM−1 and a LOD of 4.24 mM. Further, endeavours were made to immobilise alternative variations of HPAs, specifically, the crown HPA, K28Li5H7P8W48O184·92H2O, and Cu2+ substituted Krebs HPA, KxNa(10-x)Bi2W20Cu2O70(H2O)6·30H2O (with × ranging from 1 to 10), into PPy films. Initial findings from these attempts are also briefly discussed in this study.