Highly efficient and recyclable quaternary Ag/Ag3PO4-BiOBr-C3N4 composite fabrication for efficient solar-driven photocatalytic performance for anionic pollutant in an aqueous medium and mechanism insights

A simple chemical precipitation route to synthesize the quaternary composite under mild conditions is reported. The quaternary composite photocatalyst Ag/Ag3PO4-BiOBr-C3N4-1 band gap was tuned to 0.56 eV by varying the amount of C3N4 for efficient photocatalytic performance. The as-prepared photocatalysts were characterized by XRD, XPS, TEM, EDAX, BET, EIS, and UV-Vis DRS spectroscopy. The degradation of reactive red (RR 120) under visible-light illumination were evaluated. The surface plasmon resonance (SPR) effect of Ag nanoparticles enhances the absorption and utilization of visible light. The Ag/Ag3PO4-BiOBr-C3N4 composite exhibited 92.6% degradation efficiency with the removal rate 0.042 min-1 which is 5.2, 2.7 and 2.5 times greater compared to pristine Ag/Ag3PO4, BiOBr and C3N4 particles. The active species holes (h+), superoxide (center dot O2-) and hydroxyl (center dot OH) radicals were responsible for the degradation process. The 4 times of cycle experiments proved the relatively high stability of the synthesized photocatalyst. The quaternary Ag/Ag3PO4-BiOBr-C3N4 heterojunction can endorse enhanced redox capability. The faster interfacial transport was validated, for quaternary photocatalysts using the EIS Nyquist plot. The work has driven a significant guidance in designing photocatalysts with surface plasmon effect.