A facile and effective hydrothermal method for the fabrication of the Ag 3 PO 4 -graphene (Ag 3 PO 4 -GR) visible light photocatalyst has been developed to improve the photocatalytic performance and stability of Ag 3 PO 4 , and also to reduce the high cost of Ag 3 PO 4 for practical uses. The size and morphology of Ag 3 PO 4 particles could be tailored by the electrostatically driven assembly of Ag + on graphene oxide (GO) sheets and by the controlled growth of Ag 3 PO 4 particles on the GO surface. The generation of Ag 3 PO 4 and the transformation of GO to GR can be achieved simultaneously in the hydrothermal process. The improved photocatalytic activity of Ag 3 PO 4 -GR composites under visible light irradiation is attributed to high-surface-area GR sheets, enhanced absorption of organic dyes, and more efficient separation of photogenerated electron−hole pairs. The transfer of photogenerated electrons from the surface of Ag 3 PO 4 to GR sheets also reduces the possibility of decomposing Ag + to metallic Ag, suggesting an improved stability of recyclable Ag 3 PO 4 -GR composite photocatalyst. Moreover, with the advances in the large-scale production of high-quality GO, the use of GO as the starting material can also reduce the cost for the synthesis of Ag 3 PO 4 -based photocatalysts without weakening their photocatalytic activities.

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In this work, bifunctional TiO 2 /Ag 3 PO 4 /graphene (GR) composites have been prepared via the combination of ion-exchange method and hydrothermal approach, and the fabrication of "pizza-like" three-phase TiO 2 / Ag 3 PO 4 /GR composites has been achieved through the electrostatic-driven assembly of positively-charged Ag + on negatively-charged graphene oxide (GO) sheets, followed by the nucleation & controlled growth of Ag 3 PO 4 and the deposition of Degussa P25 on the GO surface. Consequently, the hydrothermal treatment leads to the generation of TiO 2 /Ag 3 PO 4 /GR composites with well-defined structures. The as-prepared composites exhibited highly efficient visible light photocatalytic activity toward organic dye molecule degradation and showed excellent bactericidal performance. This is the first report on the production of bifunctional three-phase metal oxide-Ag 3 PO 4 -GR composite materials with improved photocatalytic and antibacterial properties. The improved photocatalytic activity is attributed to the effective separation of photoexcited electron-hole pairs and fast charge transfer between components in the composite, while its excellent bactericidal performance is believed to come from intrinsic bacterial inactivation of Ag 3 PO 4 and photo-induced antibacterial activity of active oxygen-containing radicals generated in the irradiated system. The proper molar ratio of Ag 3 PO 4 /TiO 2 and the added amount of GO in the precursor have been considered to play crucial roles in the formation of bifunctional composites with promising properties. The TiO 2 /Ag 3 PO 4 /GR composite significantly decreases the percentage of expensive Agcontaining material while it reveals better photocatalytic and antibacterial performance than Ag 3 PO 4 , providing new insights into the low-cost, large-scale production of Ag 3 PO 4 -based function materials for practical applications.

In this work, the ferrocene-encapsulated Zn zeolitic imidazole framework (ZIF-8) was prepared by the self-assembly of Zn ions and 2-methylimidazole and used for the dual detection of amyloid-beta oligomers (AβO), which is the main neuropathological hallmark of Alzheimer's disease. Ferrocene is an optically and electrochemically active signal which was successfully encapsulated inside of the ZIF-8 and released by the competitive coordination between Zn ions and AβO after being treated with AβO. The released ferrocene content was monitored by ultraviolet/visible spectrophotometry and cyclic voltammetry. The dual determination of AβO played a synergetic role in the quick qualitative and precise quantitative analyses in a wide detection range of 10 −5 to 10 2 μM and good feasibility in artificial cerebrospinal fluid.

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This review summarizes the research works of non-enzymatic electrochemical sensors for the early diagnosis of Neurodegenerative disease.