SSIMS表征催化剂的表面状态和结构层次

自Benninghoven。A 提出静态二次离子质谱(Static Secondary Ion Mass Spectrometry或SSIMS)方法以来,它就成为一种极灵敏的表面分析技术。近年来,SSIMS技术在多相催化研究中的应用日益广泛。我们曾成功地用SSIMS表征过MoO_3-NiO-P_2O_5/γ-Al_2O_3催化剂的表面结构层次.本工作中,我们应用SSIMS,并结合XPS对新型催化剂MoO_-CoO/TiO_2-Al_2O_3的表面结构层次和表面状态作了研究.实验结果和我们原先用PASCA(Positron

CHARACTERIZATION OF SURFACE STRUCTURE OF NOVEL SUPPORTED CATALYSTS BY SSIMS

In this paper SSIMS (Static Secondary Ion Mass Spectrometry) combined withXPS was used for measuring the surface state and constitution of selvage layers of novelsupported catalysts MoO_3-CoO/TiO_2-Al_2O_3. Because of very high surface sensitivity,SSIMS has been used successfully in characterization of the surface state or species ofactive component supported on the surface of the carrier (TiO_2-Al_2O_3), as measuringthe intensity ratios (e. g. I114_(MoO~+)/I27_(Al~+), I59_(Co~+)/I27_(Al~+), etc. ) of different secondaryions. Also, SSIMS has been used for determining the constitution of selvage layersof novel supported catalysts MoO_3-CoO/TiO_2-Al_2O_3, as measuring the intensity of se-condary ion as a funcnion of time (e. g. I~(114)MoO~+(t), I~(59)Co~+ (t),etc. ). The results ofthe dispersed amount of active component MoO_3 on the surface of carrier by SSIMSare in line with those obtained by PASCA (Positron Annihilation Spectroscopy forChemical Analysis) and LRS (Laser Raman Spectroscopy). Furthermore, the resultsof surface state and constitution of selvage layers of novel supported catalysts MoO_3-CoO/TiO_2-Al_2O_3 can be correlated with the HDS (Hydrodesulfurization) reactivity ofthiophene at the atmosphere pressure. And the satisfactory result was obtained. Allthese mentiond above illustrate that after improving some experimental techniques,theSSIMS can be used as a powerful tool for measuring the surface state and the cons-titution of selvage layers of supported catalysts simply and directly.