Carbon-Rich Nanocomposites Based on Polyaniline/Titania Nanotubes Precursor: Synergistic Effect Between Surface Adsorption and Photocatalytic Activity

Abstract

Nowadays, there is an urgent need for efficient photocatalysts and adsorbents for environmentally relevant applications. This study investigates the effect of polyaniline (PANI) on the structure and performance of carbonized nanocomposites composed of PANI and TiO2 nanotubes (NTs), focusing on their photocatalytic degradation efficiency and dye adsorption capacity. The hypothesis was that PANI forms conductive carbon domains and stabilizes the anatase phase during thermal treatment, enhancing the performance of TiO2-NTs as photocatalysts. Nanocomposites based on PANI and TiO2-NTs (TTP) were synthesized through chemical oxidative polymerization of aniline (ANI) in the presence of TiO2-NTs using two TiO2/ANI molar ratios of 50 and 150 and subsequently carbonized at 650 ◦C, yielding CTTP-50 and CTTP-150. The novel CTTP composites and carbonized pristine TiO2-NTs (CTNT) were characterized by various techniques, including TEM, UVVis diffuse reflectance, Raman spectroscopy, XRD, and TGA. Their performance regarding dye adsorption and photocatalytic degradation under visible light was evaluated with Acid Orange 7, Methylene Blue, and Rhodamine B. CTTP-150 exhibited the highest adsorption capacity and photodegradation rate, attributed to the synergistic effect of PANI, which stabilizes the TiO2 phase and enhances visible-light absorption and adsorption.