Boosted photocatalytic and antibacterial activities of polyaniline supported tandem n-n ternary CdS-ZnO-Ag3PO4 composite under visible light irradiation

In this work, a novel polyaniline supported tandem n-n ternary heterojunction, PANI/CdS-ZnO-Ag3PO4, was prepared via impregnation method. Physicochemical properties of the as-synthesized materials were determined by AAS, XRD, TGA-DTA, UV–vis, SEM-EDX, HR-TEM, FT-IR, and PL instruments. Photocatalytic activities and antimicrobial efficiencies of the supported and unsupported heterojunctions were evaluated using methyl orange dye as a model organic pollutant and Gram negative and Gram positive bacteria as test microbes respectively. Photocatalytic and antibacterial activities of the polymer supported ternary heterojunction were found to be higher than that of binary and single forms. At optimized working conditions (12 ppm of MO, 140 mg L−1 of catalyst, at pH=6), degradation efficiencies of 95.6%, 92.1%, 84.2% and 70.0% were obtained during four cycles. Thus, supporting the ternary system not only enhanced the photocatalytic efficiency but also the stability of the ternary heterojunction. Superoxide (·O2-) and hydroxyl radicals (·OH) were the predominant reactive species involving in the degradation process. Antibacterial efficiency of polyaniline supported CdS-ZnO-Ag3PO4 composite over both Gram negative and Gram positive bacteria was found to be relatively higher than its binary and ternary counterparts revealing the potential application of this novel composite for environmental and antimicrobial applications.