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采用两步浸渍法制备钾改性的Mo/SBA-15催化剂.采用N2吸附,X射线衍射(XRD),透射电镜(TEM),紫外-可见(UV-Vis)吸收光谱,拉曼(Raman)光谱,NH3程序升温脱附(NH3-TPD),CO2程序升温脱附(CO2-TPD),H2程序升温还原(H2-TPR)等手段表征催化剂的物理化学性质.研究结果表明,在Mo0.75/SBA-15中添加K之后,有新物种钾钼酸盐生成,并且当K/Mo的摩尔比不同时,钼物种的存在状态也不同.添加钾之后,催化剂的活性和总醛(甲醛、乙醛、丙烯醛)的选择性均有所提高,并且受钾的添加量影响.在575°C时,在K0.25-Mo0.75/SBA-15催化剂上醛的收率可高达8.5%(摩尔分数).
A two-step impregnation method was used to prepare potassium-modified Mo / SBA-15 catalyst.The effects of N2 adsorption, X-ray diffraction (XRD), transmission electron microscopy (TEM), UV-Vis absorption, Raman, (NH3-TPD), CO2-TPD and H2-TPR were used to characterize the physico-chemical properties of the catalyst.The results showed that under the conditions of Mo 0.75 / KNO3 / SBA-15, K molybdate was formed, and the existence of molybdenum species was also different when K / Mo molar ratio was different.After addition of potassium, the activity of catalyst and total aldehydes (formaldehyde, Acetaldehyde, acrolein) selectivity increased, and the amount of potassium added.At 575 ° C, the yield of aldehydes on K0.25-Mo0.75 / SBA-15 catalyst can be as high as 8.5% (Mole fraction).