In Situ Polymerization of Aniline to Polyaniline With Aps/Kmno4 for Superior Photocatalytic Performance

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PANI is a multipurpose conductive polymer with significant industrial and scientific applications in disciplines ranging from energy storage and electronics to environmental and medicinal engineering. PANI is usually synthesized from monomeric aniline by in situ polymerization using a suitable oxidant or oxidizing agent. Composite oxidants are believed to provide a strategic advantage in the synthesis and modification of PANI characteristics by altering synthesis kinetics, morphology, and conductivity in ways that single oxidants cannot. The most commonly employed ammonium persulfate (APS) oxidant for the synthesis of PANI could not generate high-quality PANI due to temperature sensitivity, potential overoxidation, and effects on polymer shape and stability. Hence, an appropriate composite oxidant must be found for synthesizing PANI and possibly other conducting polymers. In this study, three types of PANIs were produced by APS as a single oxidant and APS/K2Cr2O7 and APS/KMnO4 as composite oxidants via in-situ polymerization of aniline. The synthesized PANIs were characterized using various characterization techniques, and the influence of the oxidants on the structure, morphology, and other properties was discussed. Finally, the photocatalytic activities of the synthesized PANIs were tested on the photo-deterioration of the Congo Red dye in an aqueous solution exposed to visible light. The PANI sample made with APS/KMnO4 had the highest and best photocatalytic activity of all the samples because almost 100% degradation was achieved within 2 h compared to PANI-APS and PANI-APS/K2Cr2O7 with 94% and 86%, respectively, after 2 h. The high photocatalytic activity of PANI-APS/KMnO4 might be related to its smaller crystallite size and hence larger surface area than that of the other samples. The surface areas of PANI-APS, PANI-APS/K2Cr2O7, and PANI-APS/KMnO4 were 15.67, 12.29, and 25.67 m2 g−1. Therefore, the difference in the constituents of the oxidants is responsible for controlling the size, structure, morphology, surface area, and photocatalytic activities of the final products. Therefore, this research revealed the capability of KMnO4 in the development of effective composite oxidants and offers new insight into the use of different oxidants in the adjustment of PANI’s shape, structure, and other characteristics