摘要：
采用蒸氨法制备Cu/SiO2催化剂,分别考察气相二氧化硅( SiO2-aer)、硅胶( SiO2-gel)和碱性硅溶胶( SiO2-sol)对Cu/SiO2催化剂催化甲醇裂解制氢性能的影响,并采用N2吸附-脱附、N2O化学吸附、电感耦合等离子体原子发射光谱法(ICP-AES)、X射线衍射(XRD)、H2程序升温还原(H2-TPR)、透射电子显微镜( TEM)和X射线光电子能谱( XPS)等方法对催化剂进行表征.结果表明,硅源对Cu/SiO2催化剂的活性具有较大影响.以碱性硅溶胶作为硅源制得的Cu/SiO2-sol催化剂比表面积较大,活性中心粒径较小且分散均匀,这些使得其制氢性能优于其他两种硅源为载体所制备的催化剂.在反应温度280°C,反应压力1 MPa,甲醇质量空速0.6 h-1的条件下,相较于Cu/SiO2-aer和Cu/SiO2-gel催化剂,Cu/SiO2-sol催化剂的甲醇转化率分别提高10%和7% ,气相副产物CH4和CO2浓度也有所降低,该催化剂上的甲醇转化率和气体收率分别达到98.4%和96.7% .%Cu/SiO2catalysts were prepared via ammonia evaporation method, using fumed silica ( SiO2-aer) , silica gel (SiO2-gel) and alkaline silica sol (SiO2-sol) as the silica sources and their catalytic performance in methanol decomposition were investigated.The catalysts were characterized by N2adsorption-desorption, N2O chemisorption, inductively coupled plasma atomic emission spectroscopy ( ICP-AES ) , X-ray diffraction ( XRD) , H2temperature programmed reduction ( H2-TPR) , transmission electron microscope ( TEM) and X-ray photoelectron spectroscopy( XPS) .The results indicate that silica source can affect the decomposition activity of Cu/SiO2catalysts.The Cu/SiO2-sol catalyst prepared with alkaline silica sol exhibits larger surface area, smaller active site size and more uniform dispersion of Cu.Therefore, it gives Cu/SiO2-sol a better decomposition performance than other catalysts.Methanol conversion on Cu/SiO2-sol is 10% higher than that on Cu/SiO2-aer, and 7% higher than that on Cu/SiO2-gel.Additionally, byproducts concentration on Cu/SiO2-sol is considerably lower than other catalysts.Under the reaction conditions of 280 °C, 1 MPa and 0.6 h-1of WHSV, methanol conversion of 98.4% and gas yield of 96.7% can be achieved.
