Aidong Tang

Synthesis of tin oxide nanoparticles by mechanochemical reaction

Abstract The synthesis of tin oxide (SnO 2 ) nanoparticles by mechanochemical reaction (SnCl 2 +Na 2 CO 3 ) with NaCl as diluent and subsequent thermal treatment was investigated using differential thermal analysis (DTA), thermogravimetric analysis (TGA), X-ray diffraction (XRD), infrared spectroscopy (IR) and transmission electron microscopy (TEM). Heat treatment of the as-milled powder at 600xa0°C in air and removal of NaCl through washing produced the SnO 2 nanocrystallites with an average crystal size of about 28 nm, varying with the thermal treatment temperature. The mechanism of nanocrystallites growth is discussed.

Amine-Impregnated Mesoporous Silica Nanotube as an Emerging Nanocomposite for CO2 Capture

Pristine halloysite nanotubes (HNTs) were pretreated to produce mesoporous silica nanotubes (MSiNTs), which was further impregnated with polyethenimine (PEI) to prepare an emerging nanocomposite MSiNTs/PEI (MP) for CO2 capture. Thermogravimetric analysis (TGA) was employed to analyze the influences of PEI loading amount and adsorption temperature on CO2 adsorption capacity of the nanocomposite. The Brunauer-Emmett-Teller (BET) surface area (SBET) of MSiNTs was six times higher than that of HNTs, and the corresponding pore volume was more than two times higher than that of HNTs. The well dispersion of PEI within the nanotubes of MSiNTs benefits more CO2 gas adsorption, and the adsorption capacity of the nanocomposite could reach 2.75 mmol/g at 85 °C for 2 h. The CO2 adsorption on the nanocomposite was demonstrated to occur via a two-stage process: initially, a sharp linear weight increase at the beginning, and then a relatively slow adsorption step. The adsorption capacity could reach as high as 70% within 2 min. Also, the nanocomposite exhibited good stability on CO2 adsorption/desorption performance, indicating that the as-prepared emerging nanocomposite show an interesting application potential in the field of CO2 capture.

Mechanosynthesis and gas-sensing properties of In2O3/SnO2 nanocomposites

We report the successful synthesis of 30 wt% In2O3/SnO2 nanocomposites by heating the precursor obtained via a mechanochemical reaction, and investigate their gas-sensing properties. The samples were characterized by means of x-ray diffraction, scanning electron microscopy and x-ray photoelectron spectroscopy. Subsequent thermal treatment of the precursor for 2 h in air at 700 °C resulted in the formation of In2O3/SnO2 nanocomposites with an average crystal size of about 22 nm. In comparison to pure SnO2, the gas sensor fabricated from the as-synthesized In2O3/SnO2 nanocomposites has an excellent gas-sensing performance, such as high sensitivity (93 for 1000 ppm C2H5OH), a rapid response rate (within 5 s for 90% response and recovery times) and high selectivity to ethanol. To explain the enhanced sensitivity of the In2O3/SnO2 gas sensor, the gas-sensing mechanism is discussed.