Preparation And Gas Sensing Properties Of Tin Dioxide Nanoparticles

At present, atmospheric pollution is regarded as the most serious pollution among of all the environmental problems. Thus, it is very necessary to detect and monitor atmospheric contaminants effectively. Metal oxide semiconductor gas sensing materials based on Sn O2 are the most important research materials at sensor field due to their high chemical stability and superior electrical conductivity. Adding dopants into Sn O2 can improve electronic transmission efficiency and sensing performance. The main research contents are as following.(1) One-dimensional alkaline-earth metals composited Sn O2 nanorods(Ae/Sn O2) with uniform size were fabricated via electrospinning technique, combined with thermal treatment. The TEM studies show that the nanoparticles size of Ae/Sn O2 is 5–7 nm, which is smaller than that of the pristine Sn O2 nanorods attached by 20 nm nanoparticles. The MS analyses indicate that the carrier density and conductivity of Sr/Sn O2 nanocomposites are obviously increased. The Sr/Sn O2 nanocomposites present superior gas sensing performance toward NH3 at room temperature with lower detection limit of 10 ppm and faster response time 16 s than those of the pristine Sn O2.(2) The In2O3–composited Sn O2 nanorods(ICTOs) heterostructures have been prepared by electrospinning and calcination. It is found that In2O3 could improve the carrier density and oxygen deficiency of Sn O2. In particular, the 3ICTO(Sn:In atom ratio of 25:0.3) nanorods show an excellent sensing response towards different concentration NOx at room temperature. The highest sensing response is up to 8.98 for 100 ppm NOx with fast response time 4.67 s and the lowest detection limit is down to 0.1 ppm.(3) The Co3O4-composited Sn O2 nanotubes(CCTOs) have been fabricated by coaxial electrospinning. The p-n heterostructures that are regarded as electronic transmission channels, formed between n-type Sn O2 and p-type Co3O4. Meanwhile, the nanotube structure is conducive to gas transmission and improve the gas sensing properties. The CCTO5 presents the best sensing response to 100 ppm NOx with the highest sensing response 30.04 and the fastest response time 4 s at room temperature.