Performance analysis of novel Bi6Cr2O15 coupled Co3O4 nano-heterostructure constructed by ultrasonic assisted method: Visible-light driven photocatalyst and antibacterial agent

Abstract The unreported Bi6Cr2O15-Co3O4 nano-photocatalyst was prepared via facile sono-chemical route and fabricated a binary heterojunction. HRTEM analysis represents the spherical shape of Bi6Cr2O15-Co3O4. UV–vis DRS showed bandgap shift from 1.95 eV (Bi6Cr2O15) and 2.67 eV (Co3O4) to 2.25 eV for Bi6Cr2O15-Co3O4 with visible-light sensitization. X-ray photoelectron spectroscopy (XPS) confirmed chemical states (Co2p, Cr2p, Bi4f and O1s). The dye degradation efficiency of Bi6Cr2O15-Co3O4 was highly boosted up to 3.8 to 8.8 times and the kinetic rate constant was 0.0062 min−1 compared with pristine counter parts (Bi6Cr2O15 = 0.0016 min−1; Co3O4 = 0.0007 min−1). The remarkably enhanced photocatalytic activity was ascribed to its higher specific surface area (27.118 m2/g) and the existence of a synergic effect between pristine counter parts that resulted in suitable bandgap and reduced recombination of e-/h+ pairs. The Bi2CrO6-Co3O4 showed only negligible reduction in degradation performance after six recycles showing its excellent stability and resistance to photo-corrosion. The ·OH and h+ were the key species involved in dye degradation. The Bi6Cr2O15-Co3O4 exhibited excellent antimicrobial activity against Escherichia coli and Bacillus subtilis. Therefore, Bi6Cr2O15 decorated Co3O4 nano-photocatalyst can be used as an effective candidate for environmental remediation through photocatalysis and for bactericidal applications.