Enhanced photoelectrochemical water splitting and photocatalytic degradation performance of visible light active ZnIn2S4/PANI nanocomposite

In our work, zinc indium sulfide coupled polyaniline (ZnIn2S4/PANI) nanocomposites were synthesized using chemisorption method. The substantial enhancement in the photocatalytic and photoelectrochemical (PEC) water splitting activity under visible light illumination was demonstrated. ZnIn2S4/PANI nanocomposites were shown ∼3 times improvement in the photodegradation of methylene blue (MB) dye as compared to bare ZnIn2S4 (ZIS) nanoflakes. In addition, the ZIS/PANI nanocomposite photoelectrode was exhibited ∼3 times enhancement in photocurrent density (∼260 μA/cm2 at 0.8 V vs. Ag/AgCl) as compared to ZnIn2S4 photoelectrode. However, the ZIS/PANI photoanode was demonstrated ∼5 fold enhancement in the incident photon to current conversion efficiency (IPCE) than bare ZIS. The enhancement in the photodegradation and PEC water splitting activity of ZIS/PANI nanocomposite is ascribed to extended visible light absorption, and synergetic effect of PANI along with type-II heterojunction formation, which is beneficial for separation of charge and faster transfer efficiency of photogenerated charge carriers. This study demonstrates that establishing a heterostructure system by coupling a ternary chalcogenide semiconductor with a conducting polymer is effective for photocatalytic wastewater treatment and PEC water splitting applications.