| In recent years, with the improvement of living standard and the increasing emphasis on production safety, a higher requirement for gas sensor has also been brought forward. Metal oxide semiconductor gas sensor, as the most studied and widely used gas sensors, possess high sensitivity and low price advantages compared to other gas sensors, but still suffer from poor stability and bad selectivity. Tin oxide is the most important one in all of the metal oxide semiconductor sensitive material. It always has been one of hotspots in the research of Sn O2 gas sensor to maintain high stability and good selectivity as well as high sensitivity. Carbon nanomaterials, especially graphene and carbon nanotubes came to prominence in the field of gas sensitive material.Combining tin oxide and carbon nanomaterials is now one of the major directions to prepare gas sensitive materials with good comprehensive performances. In this paper, the composite of carbon black and Sn O2 was one-step synthesized by the pyrolysis of acetylene and tests were taken to get the gas sensing property of several gases. Composition and morphology of the carbon decorated Sn O2 were inverstigated by XRD, EDS, Raman and TEM respectively, and the annealing effect to the complex structure and gas sensitivity were also studied and analysed in this paper. A continuous layer was formed on the Sn O2 nanoparticles after the carbon decorating process and the composite turned out to be lower sensitive compared with pure Sn O2, probably because the carbon layer depressed the surface reaction between gas molecules and Sn O2. After annealing treatment, the carbon-decorated Sn O2 was synthesised and the response to 1000 ppm C2H2 at working temperature of 370 oC reached a value of 106.3, which is much higher than that of other materials reported. TEM analysis reveals that the carbon layer on Sn O2 convert to discontinuous hemispheric nanoparticles after annealing treatment. It is proposed that the gas sensing proformance was enhanced due to Schottky Barrier formed between Sn O2 nanoparticle and carbon nanoparticles. Besides, the agglomeration of carbon-decorated Sn O2 was apparently improved after anneal.A potential cataluminescence transparent glass was prepared by high temperature sintering method using Sn O2 and Ce O2 powder in boron oxide crucible. The reaction proposed initially are the high-temperature reduction of stanic oxide(Sn O2) into stannous oxdie(Sn O), which disproportionates at 600 ℃into liquid metallic tin and stannic oxide. Cerium oxide loses oxygen atom as well and convert to Ce3+ ion which is more stable at high temperature. All the oxygen generated from the reduction of Sn O2 and Ce O2 will react with boron oxide in the crucible next, during this process, the B2O3 transparent luminescent glass was prepared with Ce3+ ion embedded in the random boron-oxygen network. Fluorescence spectra reveals that the as prepared Sn O2-B2O3-Ce O2 glass can be a potential candidate of cataluminescence gas sensitive materials with a emission band centered at 433 nm and three excitation centered at 217 nm, 281 nm, 375 nm. |
PDF Full Text Request