Multi-dimensional Nanomaterial Structure Design And Its Application In The Field Of Catalysis And Gas Sensitivity

Nanostructured materials have played an important role in environmental protection,energy,electrochemistry and other fields due to their unique physicochemical structure,especially in the field of catalysis and gas sensitivity.The structural composition of different nanomaterials has a great impact on the catalytic and gas-sensitive fields.Therefore,we designed and developed WO₃ nanotubes with special structural functions to be applied in the gas-sensitive field and Cu/SiO₂ nanometer core-shell to be applied in the catalytic field,and evaluated their applications in these two fields.WO₃ nanotube arrays were successfully grew up onto a Si substrate covered with WO₃ thin film by thermal evaporation method.Variout characterization techniques indicated that these nanotubes show a hexagonal shape at their tips and the side planes of the tubes are well-faceted.The diameter of nanotubes is uniform and ranges from 50 to120 nm.Furthermore,the H₂S sensing performance of WO₃ nanotube arrays was analyzed.The sensor exhibited the maximum response of 7.3 to 10 ppm H₂S at 150 ℃.Moreover,good response/recovery to H₂S gas in the concentration range of1-100 ppm and high selectivity were obtained.The sensing results suggested that WO₃ nanotube array sensor exhibited good sensing performance at low temperature,which is beneficial to saving power and integrated device.The catalyst was prepared by hydrothermal method with copper acetate as the copper source to obtain MOF template uniformly coated on the surface of silica.After calcination,the highly dispersed and uniform copper nanoparticles with a size of about 2.2 nm were loaded on the surface of silica（surface area of 154 m2g-1 and dispersibility of 49.4%）.The results showed that 100% conversion of dimethyl oxalate DMO and over 95% selectivity of glycol EG was achieved by the catalyst（Cu/SiO₂-MOF）at 200 ℃ and 2 MPa,with good catalytic performance.For comparison,the active sites of Cu/SiO₂ catalyst prepared by direct hydrothermal reaction of copper acetate and silicon dioxide have a serious agglomeration(surface area of 70m²g^-1 and dispersion of 10.8%).The conversion rate of catalyst was 86.9% and EG selectivity only was 46.6%,with low catalytic activity.Therefore,the research in this paper shows that nanomaterials are widely used and can effectively improve theproperties of materials in different fields.