Morphology-controllable fabrication of Ag@MoS2 composites with improved antioxidant activities at low Ag loading

Silver (Ag) has been regarded as a significant antioxidant widely used in biosystem. Nevertheless, the loading level of Ag nanospecies needs to be controlled to prevent their potential risk to human health. Herein, nanocomposite consisting of Ag and molybdenum disulfide (MoS 2 ) has been readily synthesized via a template solvothermal method. Characterized by SEM, TEM and EDX, the Ag@MoS 2 composite morphology including nanoflower , hollow sphere and solid sphere could be well controlled by adjusting solvent type and precursor-template ratio during the synthesis process. The composite structure of all three morphologies was further confirmed by XRD, Raman and N 2 adsorption-desorption measurements. Ag@MoS 2 nanoflower and hollow sphere , in which nanosized Ag was anchored (or encapsulated) within MoS 2 nanosheets, obviously boosted the radical (1,1-diphenyl-2-picyrl, DPPH and nitride oxide, NO) scavenging efficiency (minimum IC 50,DPPH  = 26 μg/mL while IC 50,NO  = 46 μg/mL) with an Ag dosage much lowered to merely 7∼20 μg/mL. As a contrast, weaker activity of radical scavenging could be observed for Ag@MoS 2 solid sphere . Our work will shed new lights on the cost-effective strategy to obtain a biosafe antioxidant.