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Composite materials consisting of reduced graphene oxide and LiNi0.5Mn1.5O4 were in-situ prepared by a simple one-step hydrothermal-treating method. The physical property and electrochemical performance of the composite materials were characterized by X-ray diffraction (XRD), Raman spectroscopy, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), cyclic voltammetry (CV), charge/discharge testing and electrochemical impedance spectroscopy (EIS). The results demonstrate that the graphene oxide is partially reduced and uniformly in-situ anchored on the surface of LiNi0.5Mn1.5O4. As a result, the specific surface area of the composite material dramatically increases from 0.2488 m 2 •g-1 to 8.71 m 2 •g-1 and the initial specific discharge capacity improves from 125.8 mAh•g-1 to 140.2 mAh•g-1 , respectively. Furthermore, the capacity retention maintains 95.8 % after 100 cycles and the electrode polarization has significantly been lessened. At rates of 1 C, 2 C and 5 C, the composite material with 5 % reduced graphene oxide can deliver much higher capacities than the pristine LiNi0.5Mn1.5O4. Moreover, AC impedance test results show that the interfacial charge transfer impedance obviously reduced. It's confirmed that the introduction of reduced graphene oxide through hydrothermal treating is effective to enhance the electrochemical performance of the composite material.

Visible light-driven photocatalytic inactivation of Escherichia coli was performed using hydroxyapatite-supported Ag3PO4 nanocomposites (Ag3PO4/HA). The antibacterial performance was evaluated by the methods of zone of inhibition plates and minimum inhibitory concentration test. X-ray diffraction (XRD) and transmission electron microscopy (TEM) were employed to investigate the instability and transformation of the nanocomposite by comparing the crystalline, phase, and the morphology before and after exposure to Luria-Bertani culture medium under visible light irradiation. Ag3PO4 nanoparticles on the support were found to be shortly transformed into AgCl due to high chloride concentration of Luria-Bertani culture medium. The AgCl/HA nanocomposite showed both excellent intrinsic antibacterial performance contributed by the released silver ions and visible light-induced photocatalytic disinfection toward E. coli cells. This dual antibacterial function mechanism was validated by trapping the hydroxyl free radical and detecting the silver ions during the photocatalytic antibacterial process. The morphological change of E. coli cells in different reaction intervals was obtained by scanning electron microscopy (SEM) to complementally verify photocatalytic inactivation of E. coli. This work suggests that an essential comparison study is required for the antibacterial materials before and after the photocatalytic inactivation of bacterial cells using Ag3PO4 nanoparticles or Ag3PO4-related nanocomposites in mediums containing high-concentration chloride ions.

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