Electrochemical and Optical Insights into Interfacial Connection for Fast Pollutant Removal: Experimental Study of g-C3N4/BiOCl Heterojunction for Rhb and MO Photodegradation

Developing efficient heterojunction photocatalysts is essential to address the challenge of degrading persistent organic pollutants. In this study, a multi-scale characterization strategy was employed to investigate the implications of interfacial connectivity between synthesized graphitic carbon nitride (g-C3N4) /bismuth oxychloride (BiOCl)e removal of Rhodamine B (RhB) and Methyl Orange (MO). Morpho-structural characterizations, including Scanning/Transmission Electron Microscopy (SEM/TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and N2 physisorption (Brunauer–Emmett–Teller (BET)) analyses, confirmed the successful construction of an intimate interfacial contact between g-C3N4 and BiOCl. The optimized composite (15% g-C3N4/BiOCl), prepared via a one-step hydrothermal method, exhibited enhanced photocatalytic performance following pseudo-first-order kinetics described by the Langmuir–Hinshelwood model, with apparent rate constants of 0.166 min−1 for MO and 0.519 min−1 for RhB. Under visible-light irradiation, degradation efficiencies of 98% for MO (120 min) and 99% for RhB (35 min) were achieved, outperforming the pristine components. Complementary optical and electrochemical analyses indicate improved light absorption and charge-separation efficiency in the heterojunction system. In addition, the photocatalyst demonstrated good operational stability over four consecutive cycles, maintaining 91.70% activity for MO and 99.76% for RhB. Overall, this work highlights the synergistic photocatalytic g-C3N4/BiOCl heterojunction and provides a valuable insight to guide the design of advanced materials for pollutant remediation.