Sulfonated graphene oxide–ZnO–Ag photocatalyst for fast photodegradation and disinfection under visible light

Abstract

Synthesis of efficient visible-light-driven photocatalyst is urgent but challenging for environmental remediation. In this work, for the first time, the hierarchical plasmonic sulfonated graphene oxide–ZnO–Ag (SGO–ZnO–Ag) composites were prepared through nanocrystal-seed-directed hydrothermal method combining with polyol-reduction process. The results indicated that SGO–ZnO–Ag exhibited much faster rate in photodegradation of Rhodamine B (RhB) and disinfection of Escherichia coli (E. coli), than ZnO, SGO–ZnO and ZnO–Ag. SGO–ZnO–Ag totally degraded RhB dye and kill 99% of E. coli within 20min under visible light irradiation. The outstanding performences of SGO–ZnO–Ag were attributed to the synergtic merits of SGO sheets, ZnO nanorod arrays and Ag nanoparticles. Firstly, the light absorption ability of SGO–ZnO–Ag composite in the visible region was enhanced due to the surface plasmon resonance of Ag. In addition, the hierarchical structure of SGO–ZnO–Ag composite improved the incident light scattering and reflection. Furthermore, SGO sheets faciliated charge transfer and reduce electron–hole recombination rate. Finally, the tentative mechanism was proposed and verified by the photoluminescence (PL) measurement as well as the theoretical finite-difference time-domain (FDTD) simulation. In view of above, this work paves the way for preparation of multi-component plasmonic composites and highlights the potential applications of SGO–ZnO–Ag in photocatalytic wastewater treatment field.