【摘要】 采用两步法制备以类水滑石为载体的VOX/Mg-Al-O催化剂,对类水滑石前驱体进行TG-DTA分析,采用XRD、FT-IR、H₂-TPR等催化剂表征手段以获得催化剂表面活性物种类型与结构。根据TG-DTA结果,类水滑石前驱体分子结构式为Mg_0.69Al_0.31（OH）₂（CO₃）_0.16×0.81H₂O。结合XRD、FT-IR和H2-TPR表征结果,可知:当钒负载量较低时,催化剂表面以还原性能好、单层分散的孤立态和聚合态钒氧物种为主;当钒负载量较高时,催化剂表面以还原性能较差的镁钒酸盐物种为主。更多还原

【Abstract】 Hydrotalcite- type materials with different V:（ Mg + Al） ratios have been prepared by incipient wetness impregnation,and characterized by TG- DTA,X- ray diffraction,FT- IR and H₂- TPR techniques. The result of TG-DTA characterization indicates the molecular structural formula of hydrotalcite precursor should be Mg_0.69Al_0.31（OH）₂（CO₃）_0.16×0.81H₂O. Combination with the characterization results of XRD,FT- IR and H₂- TPR,it can be concluded that the isolated and polymeric VO₄ species on the catalyst surface are present at lower vanadium loadings,which can be reduced more easily than samples with higher vanadium loading. With the increasing of vanadium loadings,mixed magnesium vanadate compounds appear on the catalyst surface,which are difficult to reduce by hydrogen.更多还原