Nanoparticles containing magnetic materials, such as magnetite (Fe3O4), are particularly useful for imaging and separation techniques. As these nanoparticles are generally considered to be biologically and chemically inert, they are typically coated with metal catalysts, antibodies or enzymes to increase their functionality as separation agents. Here, we report that magnetite nanoparticles in fact possess an intrinsic enzyme mimetic activity similar to that found in natural peroxidases, which are widely used to oxidize organic substrates in the treatment of wastewater or as detection tools. Based on this finding, we have developed a novel immunoassay in which antibody-modified magnetite nanoparticles provide three functions: capture, separation and detection. The stability, ease of production and versatility of these nanoparticles makes them a powerful tool for a wide range of potential applications in medicine, biotechnology and environmental chemistry.

the LIBs. Considerable improvements in the design and optimization of anode composition and structure are still required.This note reports our design and implementation of a SnS 2based nanocomposite anode for the NIBs. SnS 2 has a CdI 2 -type of layered structure (a = 0.3648 nm, c = 0.5899 nm, space group P3m1) consisting of a layer of tin atoms sandwiched between two layers of hexagonally close packed sulfur atoms. This layered structure with a large interlayer spacing (c = 0.5899 nm) should easy the insertion and extraction of guest species and adapt more easily to the volume changes in the host during cycling. This has been confi rmed by the performance of SnS 2 as a reversible lithium storage host in several studies. [ 17 ] The electrochemical properties of layered sulfi des (SnS 2 , MoS 2 , WS 2 ) were further improved by integration with graphene. The structural compatibility between the two layered compounds and the good electronic properties of graphene led to very stable composites (i.e. long cycle-life) with high reversible capacity and good rate performance in LIB applications. [ 18 ] The SnS 2 layer structure should also be viable for reversible Na + storage since, in comparison with tin and other tin-based materials, it has the largest buffer for the volume changes in Na-Sn reactions. The LIB developmental efforts also suggest layer-structured SnS 2reduced graphene oxide (SnS 2 -RGO) nanocomposites as an improved version of the SnS 2 anode.The design of the SnS 2 -RGO hybrid structure for reversible storage of Na + was based on the following materials principles: 1) a large interlayer spacing in the SnS 2 structure benefi ting Na + intercalation and diffusion, and more buffering space for benefi cial adjustment the volume changes in the host during cycling; 2) fast collection and conduction of electrons through a highly conductive RGO network; and 3) inhibition of Sn (Na x Sn) aggregation during cycling by RGO after material hybridization. The experimental results validated the expectations: the SnS 2 -RGO anode delivered a high charge (desodiation) specifi c capacity of 630 mAh g −1 at 0.2 A g −1 , and more impressively, 544 mAh g −1 after a ten-fold increase in current density to 2 A g −1 . The electrode was also very stable to cycling; providing a nearly unvarying capacity of 500 mAh g −1 at 1 A g −1 even after 400 charge-discharge cycles.The SnS 2 -RGO nanocomposite was produced by a facile hydrothermal route from a mixture of tin (IV) chloride, thioacetamide (TAA) and graphene oxide (GO) (details in the Experimental Section). In the comparison of the X-ray diffraction (XRD) patterns of the SnS 2 -RGO composite, SnS 2 and GO in Figure 1 a, GO only displayed a single diffraction peak at 10.9° from the (002) planes. [ 19 ] The powder XRD patterns of SnS 2 and The idea of sodium-ion batteries (NIBs) as a substitute of lithium-ion batteries (LIBs) for grid-scale energy storage was initially driven by cost considerations. [ 1 ] Research in the last several years has shown that NIBs are not necessar...

This review overviews the recent development of nanomaterials for the application of electrochemical non-enzymatic glucose biosensors. The electrocatalytic mechanism and glucose sensing performance of a variety of nanostructured materials including metallic nanoparticles, metal oxides, metal complexes, alloys and carbon nanomaterials are discussed. The merits and shortfalls of each nanomaterial as electrocatalyst for non-enzymatic biosensing are evaluated and the prospects of non-enzymatic glucose biosensors are presented.

Much attention has been paid to exploring electrode materials with enhanced supercapacitor performance as well as relatively low cost and environmental friendliness. In this work, NiMoO4 nanospheres and nanorods were synthesized by facile hydrothermal methods. The hierarchical NiMoO4 nanospheres were about 2.5 μm in diameter and assembled from thin mesoporous nanosheets with a thickness of about 10-20 nm. The NiMoO4 nanorods were about 80 nm in diameter and about 300 nm to 1 μm in length. Their electrochemical properties were investigated for use as electrode materials for supercapacitors (SCs). The NiMoO4 nanospheres exhibited a higher specific capacitance and better cycling stability and rate capability, which were attributed to their large surface area and high electrical conductivity. The specific capacitances were 974.4, 920.8, 875.5, 859.1, and 821.4 F/g at current densities of 1, 2, 4, 6, and 10 A/g, respectively. Remarkably, the energy density was able to reach 20.1 Wh/kg at a power density of 2100 W/kg. After 2000 cycles, the NiMoO4 nanospheres still displayed a high specific capacitance of about 631.8 F/g at a current density of 5 A/g. These results implied that the hierarchical NiMoO4 nanospheres could be a promising candidate for use as high-performance SCs.

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