Preparation Of Natural Silicate Nanometer Tube Compound Catalyst And Research Of Their Heat Catalytic Performance

Nanomaterials with the distinct property have been applied gradually in diverse domain.While the synthesized nanomaterials have some defects such as low output, high cost.What more,these materials pollute the environment severely.All the defects restrict the development and application of synthesized nanomaterials.The natural nanometer mineral can become rare nanomaterials with excellent natures after been dealed with properly.The natural nanometer mineral is superior to the synthesized nanomaterials in output and cost.In this paper,the natural silicate nanometer mineral(HNT) was selected and characterized by means of Scanning electron microscope(SEM),Transmission electron microscope(TEM),Energy dispersive spectroscopy(EDS),X-ray diffraction(XRD),Infrared Spectroscopy (IR),Brunauer-Emmer-Teller(BET),Differential Scanning Calorimetry(DSC) and Thermogravimetric analysis(TG).It was also studied as catalysis supports and used to prepare compound catalyst.Microstructure of HNT such as crystallographic structure,grain size,particle morphology,element analysis and thermal stabilization were characterized.The results indicated that HNT was high quality mineral.It had a short cylindrical shape and a tubular morphology,high specific surface area,as well as strength and excellent thermal stability,which makes it used as catalysis supports.According to the results of DSC,we got the catalytic characteristic of HNT powder on the high temperature decomposition of ammonium perchlorate(AP).It could make the temperature of high temperature exothermic peak of AP decrease 48℃.HNT/NiO,HNT/MnO₂ and HNT/ZnO composite particles were prepared by the methods of fast precipitation,redox and static adsorption respectively.The composite particles obtained had been characterized by XRD,TEM and High Resolution Transmission Electron Microscope(HRTEM).The results showed that the nano-particles were coated uniformly on the surface of HNT.To analyze the catalytic effect of the composite particles on the thermal decomposition of AP,the comparison sample by simply mixing metal or metal oxide particles and HNT with AP respectively,had been prepared.DSC were used to characterize their catalytic performance.Results indicated that the composite particles and more pure nanoparticles had catalytic effect on AP thermal decomposition.They made the high temperature and low temperature decomposition peak of AP become a single decomposition peak and changed the mechanism of thermal decomposition.The catalytic performance of the composite particles were superior to that of the simply mixed sample in the same quantity of AP. DSC results showed the obtained HNT/NiO,HNT/MnO₂ and HNT/ZnO composite particles could make the high temperature decomposition of AP decrease 153℃,159℃,163℃respectively.HNT/ZnO had the strongest characteristics again.These demonstrated that the composite particles had the catalytic performance to AP.HNT/Cu composite particles were prepared by using electroless plating technique.The composite particle obtained had been characterized by XRD,TEM and HRTEM.The testing results showed that Cu nanoparticles with the average size of about 5 nm had been deposited on to the surface of HNT.According to the results of DSC,we got the catalytic characteristic of HNT/Cu on the high temperature decomposition of AP.They could make the temperature of high temperature exothermic peak of AP decrease 158℃.At the same time,AP releases more energies. Therefore,HNT/Cu compound particle was a fine catalyst to AP.Finally,We analysed the catalytic mechanism of HNT compound catalyst.When the nanoparticles were coated on the surface of HNT,the nanaoparticles' surfaces were increased and the reunion phenomenon was suppressed.At the same time,the dispersivity and catalyzed efficiency of the nanaoparticles to AP were also enhanced. As nanometer level material,HNT has the open style hole structure and high surface. There are many spots with catalytic activity on the surface of HNT,so HNT has the catalytic effects on the thermal decomposition of AP.The gas which AP decomposes can contact to the active position of HNT compound particles immediately.It is advantageous for the compound particles to participate in the chemical reaction.HNT can adsorb the gas in catalyst periphery strongly,which will accelerate catalyst and the gas response.Therefore,HNT compound catalyst have stronger performance to AP compared with the independent catalyst.