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以XPS法证明了铬与磷的配比及原料铬的价态是影响Cr-P-SiO_2催化活性的最主要因素。考察了在反应过程中催化剂表面状态的变化。从P_(2p)光电子谱带强度的增加,发现催化剂中的磷在反应过程中逐渐向表面迁移,同时从Cr_(2p~(3/2))光电子谱的解迭中发现在反应过程中催化剂表面Cr(Ⅲ)的量逐渐在增加。研究了随着这些变化而引起的催化活性的差异,认为磷向表面迁移是Cr-P-SiO_2催化剂永久性失活的主要原因。
XPS method to prove that the ratio of chromium and phosphorus raw materials and valence of chromium is the most important factor affecting the catalytic activity of Cr-P-SiO 2. The change of the surface state of the catalyst during the reaction was examined. From the increase of the intensity of the photoelectron band of P 2p, it was found that the phosphorus in the catalyst gradually migrated to the surface during the reaction. At the same time, it was found from the solution of 2p 3 3/2 photoelectron spectra that the catalyst The amount of Cr (III) on the surface gradually increases. The differences of the catalytic activities caused by these changes were studied. It is considered that the migration of phosphorus to the surface is the main reason for the permanent deactivation of the Cr-P-SiO 2 catalyst.