SÍNTESE, CARACTERIZAÇÃO E POSSÍVEIS APLICAÇÕES DE COMPÓSITOS DE α-MoO3 EM MATRIZES POLIMÉRICAS DE POLIANILINA E POLIPIRROL

Abstract

The focus of this work was to obtain composites of Polyaniline (Pani) and Polypyrrole (Ppy) modified with α-MoO3, characterize and study possible fields of application of these materials in degradation photocatalysis and their capacitance. The oxide was synthesized via reflux in an acidic envirorment, thus eliminating the calcination step required in the usual obtaining routes. 3 oxide composites with Pani matrix were obtained, varying the polymerization time and 3 composites with PPy matrix, varying the oxide concentration. The materials were characterized via SEM, FTIR, EDS, XRD and zeta potential. For the oxide, the SEM shows a lamellar structure in the order of nanometers wide, the FTIR shows the characteristic bands of the α phase, as well as the XRD, the EDS shows only the presence of Molybdenum oxide without the presence of contaminants and the potential zeta has a negative surface charge. For Pani, the SEM and XRD indicate an excellent assimilation of the charge in the polymer after 24 hours of polymerization, a good assimilation with little charge on the surface after 5 hours and a large amount of charge on the surface after 40 minutes of polymerization. The FTIR presents the characteristic bands of Pani without major changes in the band region caused by the oxide. The EDS shows the presence of carbon and nitrogen in the Pani structure, chlorine that functions as a counter-ion and oxygen and sulfur from the polymerization process. Pani's zeta potential is positive. For PPy, SEM and XRD demonstrate that the polymer structure has many voids within the network and that it is in these voids that the oxide enters, not being completely internalized by the polymer. The FTIR shows the characteristic bands of PPy, without major changes due to the oxide, and the EDS shows only the carbon and nitrogen of the structure, as well as chlorine, sulfur and oxygen from the polymerization process. In the degradation photocatalysis, the oxide did not show any degradation of the methyl orange dye (MO), Pani only adsorbed the MO, and the adsorption limit was then calculated at 167.55 mg/g of polyaniline and adsorption rate calculated at 0 .84mg per gram of polyaniline. Pani's composites did not adsorb the dye, but degraded it through catalysis, with the worst result being the composite with the most oxide on the surface. In the photocatalysis of methylene blue (MB), the composites and the polymer did not react, while the oxide degraded it by photocatalysis. In electrochemical studies, the presence of oxide in the composites promoted an improvement in the electrode current response, with the composite presenting the best results in cathodic and anodic peak intensity, as well as the highest calculated capacitance, both for Pani and PPy.