Strategic combination of metal–organic frameworks and C3N4 for expeditious photocatalytic degradation of dye pollutants

The potential of fabricated silver and bismuth Co–N-doped imidazolate embedded into graphitic nitride BiO-Ag(0)/C3N4@ZIF-67 for the degradation of Methylene blue (MB) and Congo red (CR) dyes have been reported. The synthesized materials were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy photoluminescence (PL) spectroscopy, and electrochemical impedance spectroscopy (EIS). The band gaps of ZIF-67, C3N4 and composites were calculated using Tauc plot. Besides, it was revealed that incorporation of silver, bismuth, and C3N4 reduced the band gap energy to 2.2 eV. The introduction of metallic species in the precursors promoted better charge separation behavior towards photogenerated electron and hole in the heterojunction composite. Two perilous organic dyes; MB and CR were degraded under natural sunlight irradiation. The photocatalytic efficiency of BiO-Ag(0)/C3N4@ZIF-67 for the removal of CR and MB significantly increased compared to bare ZIF-67. The enhanced photocatalytic activity of BiO-Ag(0)/C3N4@ZIF-67 is attributed to the higher surface area and Plasmon effect of noble silver metal. The solar light-triggered degradation of MB and CR yielded efficient efficiency of 96.5 and 90% for 10 mg/L of dye solution each. Additionally, the effect of pH was evaluated for optimizing degradation of CR and MB dyes. The kinetics studies of both CR and MB were clarified according to Langmuir model. The reusability and quenching investigation of active species were carried out to discover find catalytic potential of the composite. Besides, possible dye degradation mechanism was proposed for BiO-Ag(0)/C3N4@ZIF-67. The obtained results indicated that solar-light triggered photocatalyst BiO-Ag(0)/C3N4@ZIF-67 can be employed as a promising approach for photocatalytic elimination of organic pollutants.