Biogenic synthesis of g-C3N4/Bi2O3 heterojunction with enhanced photocatalytic activity and statistical optimization of reaction parameters

A facile and efficient biogenic method was adopted to synthesize Bi2O3 and g-C3N4/Bi2O3 nanocomposites using Eichhornia crassipes plant extract. These composites were characterized by various analytical tools such as XRD, FTIR, SEM, TEM and UV-DRS. Bismuth oxide and g-C3N4/Bi2O3 show varied optical and photocatalytic properties due to the differences in their band gap. Here, Box-Behnken design (BBD) combined with Response Surface Methodology (RSM) has been used to optimize the coupled effect of independent parameters for the dye degradation. The synthesized g-C3N4/Bi2O3 nanocomposite exhibit excellent photocatalytic activity for the degradation of malachite green (MG) dye. Total Organic Carbon (TOC) analysis unveiled 78% photomineralization of MG over g-C3N4/Bi2O3 in 5 h. The p-n junction of g-C3N4/Bi2O3 with better oxidative ability and effective charge separation is the primary reason for its improved photocatalytic activity. The modified photocatalyst shows satisfactory catalytic activity and reusability towards photodegradation of common water pollutant MG up to 4 cycles. They offer great potential in the field of photocatalysis due to their superior efficiency and applications in environmental remediation.