Design and synthesis of PANI/GO/MoS2 nanocomposites via oxidative polymerization for efficient photocatalytic applications: organic pollutant degradation and hydrogen generation

Abstract

This study focused on preparing a ternary nanocomposite (PANI/GO/MoS₂) using an oxidative polymerization technique. The composite incorporated polyaniline (PANI), graphene oxide (GO), and molybdenum disulfide (MoS₂) in different weight ratios. Comprehensive characterization studies were performed including UV-vis-DRS, PL, XRD, XPS, BET, and EDS to evaluate the material's crystallinity, purity, porosity, and optical properties. FESEM imaging revealed the porous nature of PANI, the exfoliated structure of GO, and the nanosphere morphology of MoS₂ (35–55 nm in diameter). This composite was tested for its effectiveness in degrading methyl orange (MO) dye and generating green hydrogen via visible-light-driven water splitting. Within 120 minutes, it achieved around 81.23% detoxification and 99% removal of MO dye. The degradation process adhered to first-order kinetics with a rate constant 7.1 times higher than that of pure PANI, 22 times higher than that of GO, 6.35 times higher than that of MoS₂, and 9.26 times greater than that of the commercial TiO₂-P25 photocatalyst, indicating strong synergy among the components. The study also examined the impact of various reaction parameters like pH, illumination area, catalyst dosage, and scavengers on the degradation process. The reusability of the photocatalyst was assessed over six cycles, maintaining 80% stability, as confirmed by XRD analysis. GC-MS identified the intermediates and final degradation products. The nanocomposite achieved hydrogen production with an apparent quantum efficiency (AQE) of 26% using CH₃OH as a sacrificial agent, and AQEs of 22%, 19%, and 15% under acidic, basic, and neutral conditions, respectively. This research highlights the potential of ternary nanocomposites for diverse applications beyond dye degradation, including various solar-driven technologies.