Silica covered stannic oxide nanoparticles - an easily prepared robust substrate for optical sensors

This paper describes a facile way to prepare a photophysically inert sensor substrate. Stannic oxide encapsulated silica nanoparticles with average diameters between 30 and 70 nm have been prepared by one-pot reverse-phase emulsion methodology. The constituents and core/shell morphology of the nanoparticles were demonstrated by electron microscopic technology, energy-dispersive X-ray spectroscopy (EDS), and X-ray photoelectron spectroscopy (XPS). X-ray diffraction (XRD) was employed to provide additional constitutional and structural information. It has been shown that nanoparticles prepared by this method are optically clear in suspension. After anchoring optical indicators, this nanoparticle can be utilized as a sensor module both in biology and other analytical areas.

Oxygen-Deficient Stannic Oxide/Graphene for Ultrahigh-Performance Supercapacitors and Gas Sensors

The metal oxides/graphene nanocomposites have great application prospects in the fields of electrochemical energy storage and gas sensing detection. However, rational synthesis of such materials with good conductivity and electrochemical activity is the topical challenge for high-performance devices. Here, SnO2/graphene nanocomposite is taken as a typical example and develops a universal synthesis method that overcome these challenges and prepares the oxygen-deficient SnO2 hollow nanospheres/graphene (r-SnO2/GN) nanocomposite with excellent performance for supercapacitors and gas sensors. The electrode r-SnO2/GN exhibits specific capacitance of 947.4 F g−1 at a current density of 2 mA cm−2 and of 640.0 F g−1 even at 20 mA cm−2, showing remarkable rate capability. For gas-sensing application, the sensor r-SnO2/GN showed good sensitivity (~13.8 under 500 ppm) and short response/recovering time toward methane gas. These performance features make r-SnO2/GN nanocomposite a promising candidate for high-performance energy storage devices and gas sensors.