Pani Nanocomposites And Porous ZnO Nanomaterials:Synthesis And Gas-Sensing Properties

As one of the sensory organs, gas sensors could effectively and quickly detect to toxic or combustible gases, then alarm us. So they help us avoid lots of catastrophes and improve our life. Owing to provide a better life for human, the most important is to increase the sensitivity of gas sensor. So we need detect more preferable gas-sensing materials, which is for core parts of gas sensor. In recent years, the gas sensing properties show more perfect with the use of nanomaterials and nanotechnology. Therefor, the syntheses of nano-conducting polymer and porus metal oxide semiconductor(MOS) would be benefit for improving the gas sensing properties.(1) Coralline-like polyaniline micro/nano-structured material was synthesized by in-situ chemical polymerization directed by ammonium persulfate(APS) and anionic surfactant sodium dodecyl sulfate(SDS). Morphological and structural characteristics of the as-synthesized SDS/PANI were characterized by using various techniques, including Fourier transform infrared spectroscope (FT-IR) and scanning electron microscope (SEM). The results show that the as-prepared SDS/PANI is composed of numerous coralline-like PANI with about100nm in length and20nm in diameter. The sensors based on SDS/PANI and pure PANI were tested for ammonia gas. Compared with the pure PANI, the as-prepared SDS/PANI sensors have higher sensitivity, better response towards ammonia and also exhibit the higher sensitivity at room temperature.(2) Here we described a most simple method to fabricate polyaniline/acid-treated multiwalled carbon nanotube(PANI/F-MWCNTs) and pure polyaniline by in-situ chemical oxidation polymerization directed. The PANI/F-MWCNTs was characterized by Fourier transformed infrared spectra (FT-IR), Field-emission scanning electron microscopy(FE-SEM). At the same time, the sensors on the basis of PANI/F-MWCNTs nanocomposites and pure PANI were tested towards ammonia gas at room temperature.(3) Porous ZnO nanoparticle has been successfully synthesized by chemical precipitation method that carbon nanotubes (F-MWCNTs) was doped into ZnO solution, then calcining in air to make F-MWCNTs carbonization. X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) surface area and Fourier Transformed Infrared (FT-IR) were used to characterize the morphology, mesoporous structure of the sample. The results indicated that the sample with dispersed structure and good dispersion was wurtzite structure ZnO nanoparticle. The gas-sensing properties of the pure nanoparticle were studied. The results revealed that the gas sensors based on ZnO exhibited a higher sensitivity and selectivity to ethanol at200℃.