SnO 2 is an n-type wide band gap (E g = 3.6 eV) metal oxide semiconductor (MOS) that has been widely studied, due to its low cost, non-toxicity and simple preparation process, and it has become the most important sensitive material for the preparation of gas sensors. However, the SnO 2 sensor still has some defects of high operating temperature and low response, which hinders its practical application. In this work, SnO 2 /SnS composites were prepared by hydrothermally growing SnS nanoparticles on the surface of electrospun hollow SnO 2 nanotubes with high porosity. Results show that the SnO 2 /SnS gas sensor based on the heterojunction has a much higher response of 375 to 50 ppm NO at 130 ℃ than that of pure SnO 2 sensor, as well as rapid response/recovery (26 s/90 s), excellent selectivity (12 times that of H 2 S), repeatability and stability (225–250 to 20 ppm NO). Its enhanced sensing property may be attributed to the synergistic effect of the formation of homologous cations heterojunction and unique micro-structure of SnO 2 /SnS composite, which could facilitate efficient charge transfer and provide more active sites (such as vacancy, point defects) for NO adsorption and reaction. This experiment provides a new idea for the development of SnO 2 gas sensors with excellent properties, which can meet the detection of toxic and harmful gas.
Tin-based compounds have incurred tremendous attention due to their higher specific capacities than their analogues for lithium storage. Unfortunately, the undesirable electrical conductivities and huge volume variations during cycling processes coupled with Li + intercalation and de-intercalation will lead to severe capacity fading and poor cycling stability. To address these problems, nitrogen-doped carbon-coated SnO 2 /SnS (SnO 2 /SnS@N-C) composite was in situ synthesized by virtue of a simple solvothermal reaction and subsequent post-treatment. Herein, the heterostructures between SnO 2 and SnS were designed to accelerate charge transfer by using the effect of internal electric field and improve the dispersion among particles. While coating the nitrogen-doped carbon on heterostructures aimed to improve electrical conductivities and relieve huge volume alterations during the processes of Li + insertion and de-insertion. To our satisfactory, the as-prepared SnO 2 /SnS@N-C composite as anodes for lithium-ion batteries can display a high specific capacity (1050 mAh g −1 at 100 mA g −1 ), enhanced rate capability, and long cycle life (550 mAh g −1 after 100 cycles), which outperforms both SnO 2 @N-C and SnS@N-C. The promotion of electrochemical performance demonstrates that Tin-based anode materials with such optimized structures have broad prospects in the applications of energy storage field.
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