Enhanced Photocatalytic Reduction of Chromium (VI) by Polythiophene‐Graphitic Carbon Nitride Nanocomposite

Abstract The global pursuit of clean water (Sustainable Development Goal (SDG) 6) and healthy aquatic ecosystems (SDG 14) demands innovative solutions for the removal of toxic pollutants from water sources. In this research work, the novel Polythiophene‐Graphitic carbon nitride (PTh/g‐C 3 N 4 ) nanocomposite is reported for the photocatalytic reduction of chromium hexavalent (Cr (VI)). The nanocomposite is synthesized via an in situ polymerization method. X‐ray diffraction (XRD), Fourier transform infrared (FTIR) Spectroscopy, and field emission scanning electron microscopy (FE‐SEM) techniques are used to confirm the formation of PTh/g‐C 3 N 4 nanocomposite. The X‐ray photoelectron spectroscopy (XPS), Brunauer–Emmett–Teller (BET) studies, Mott–Schottky measurement, Electrochemical impedance spectroscopy (EIS) study, and zeta potential studies are performed to study the photocatalytic properties of the nanocomposite. Photocatalytic reduction of Cr (VI) in different concentrations is performed using PTh/g‐C 3 N 4 nanocomposite, and the reduction efficiency (≈90%) is superior compared with pristine Polythiophene (PTh) and Graphitic carbon nitride (g‐C 3 N 4 ). The rate kinetics for the different concentrations of Cr (VI) are also studied, and the analysis shows that it follows a pseudo‐first‐order and Langmuir isotherm model. The photocatalysis mechanism proposed based on the Mott–Schottky experiment is supported by a scavenger test. Additionally, the reusability test and energy consumption rate confirm the potential application of a photocatalyst in real‐life applications.