Comparative study of KF, KCl and KBr doped with graphitic carbon nitride for superior photocatalytic degradation of methylene blue under visible light

In this study potassium salts such as KF, KCl and KBr were doped onto g-C3N4 to form KX-g-C3N4 (X = F, Cl and Br) via a thermal method. The KX-g-C3N4 was characterized by various instrumentation techniques such as UV–visible, FT-IR, XRD, Photoluminescence, TGA, BET, Raman, SEM, EDAX, HR-TEM, and Zeta potential. KX-g-C3N4 was explored for the photocatalytic degradation of methylene blue (MB) under visible light irradiation. Among them, KF-g-C3N4 showed excellent photocatalytic degradation of methylene blue (MB) under visible light irradiation. The KF-g-C3N4 significantly reduced the electrons–holes recombination rate when compared to KCl-g-C3N4, KBr-g-C3N4 and g-C3N4. The photocatalytic degradation mechanism was also studied with KF-g-C3N4.