Facile synthesis of silver decorated reduced graphene oxide@zinc oxide as ternary nanocomposite: an efficient photocatalyst for the enhanced degradation of organic dye under UV–visible light

Abstract

Ternary combination of metal and metal oxide with reduced graphene oxide could be a novel potential photocatalyst towards highly efficient degradation of organic dyes under solar radiation. Herein, the novel ternary nanocomposite of silver nanoparticles with reduced graphene oxide and zinc oxide nanorods (Ag-rGO@ZnONR) were synthesized via in situ homogeneous coating of silver nanoparticles (Ag NPs) onto pre-assembled thermally reduced graphene oxide (rGO) encapsulated ZnO nanorods (ZnONR). The nanocomposite showed excellent aptitude towards the photodegradation of 2-chlorophenol (2-CP) under solar light irradiation. The Ag-rGO@ZnONR nanocomposite showed excellent UV–visible light harvesting due to the engineered reduced bandgap, and the Schottky barrier at the metal–semiconductor interface is expected to promote charge separation as also revealed by the optical calculations. The production of superoxide anions ·O2-\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$^{ \\cdot } {\\text{O}}_{2}^{ - }$$\\end{document} and hydroxyl radicals (·OH)\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$(^{ \\cdot } {\\text{OH}})$$\\end{document} acting as substantial reducing and oxidizing agents and further π\u2009−\u2009π stacking interactions with the aromatic ring of 2-CP provided an ultimate foundation for its 100% degradation. The photocatalyst showed high reproducibility, and 94% efficiency was observed even after three cycles. XPS chemical state analysis of C1s, O1s, Zn2p, and Ag3d confirm the variation of C\u2009=C (sp2), C–O, O=\u2009C–OH, and localization of Ag nanoparticles with rGO by confiscating the oxygen-comprising functional moieties which may be the possible reason for the enhanced photodegradation.