Ultrafast charge separation and photostability in PANI/GO/MoO3 ternary nanocomposites for dual-function solar photocatalysis: enhanced dye degradation and hydrogen evolution under visible light

Abstract

Polyaniline-based photocatalysts have attracted attention due to their favourable bandgap (2.7 eV) and significant visible light absorption (∼43%). In this study, a novel ternary nanocomposite, PANI/GO/MoO₃, synthesized via oxidative in situ polymerization, combining polyaniline (PANI), graphene oxide (GO), and molybdenum trioxide (MoO₃), was presented with different wt/wt%. Comprehensive characterization using XRD, BET, EDS, XPS, PL, and UV-vis-DRS revealed crystallinity, porosity, and superior optical properties. The FESEM image confirmed the porous morphology of PANI, exfoliated GO layers, and MoO₃ nanorods (60–80 nm). Among the composites, 2.5PGMO (GO–MoO₃: 2.5 wt% and PANI: 97.5 wt%) exhibited the highest electron lifetime (0.612 ms), significantly outperforming individual components such as PANI (0.0495 ms), GO (0.023 ms), and MoO₃ (0.022 ms). Photocatalytic activity was validated through both methyl orange (MO) degradation and solar-driven hydrogen production via water splitting. The 2.5PGMO composite achieved 98% MO removal and 70% detoxification within 120 minutes, with a reaction rate surpassing that of traditional photocatalysts. Optimal conditions, such as pH, catalyst dosage, and scavenger presence, enhanced performance. The composite shows 85% degradation of the pollutant over five cycles, and stability of the nanocomposite was confirmed by XRD and ICP-OES. In solar hydrogen production, it delivered an apparent quantum efficiency (AQE) of 30.76% using CH₃OH as a sacrificial agent, with nearly 28% AQE under varying pH conditions. This study underscores the PANI/GO/MoO₃ nanocomposite as a promising multifunctional photocatalyst for simultaneous environmental remediation and sustainable hydrogen production, paving the way for advanced solar-driven technologies.