基于简化K-M模型的加氢催化剂活性金属在载体上分散状态的研究

Investigation on the Dispersion State of Active Metal in Hydrogenation Catalyst on the Carrier Based on Simplified K-M Model

基于简化的Kerkhof-Moulijn模型,建立了应用X射线光电子能谱(XPS)定量结果研究加氢催化剂活性金属在载体表面分散状态的方法。模型充分考虑了载体比表面积、载体真密度及光电子平均自由程等对XPS定量结果的影响,结合XPS分析得到的催化剂表面活性金属与载体的原子摩尔比,可以获得活性金属在载体表面的表观粒径,从而更加直观和客观地分析活性金属的分散状态。此外,研究了活性金属负载量、载体比表面积和金属种类对分散状况的影响,比较了加氢催化剂硫化前后分散度的差异。结果表明,硫化过程将使金属元素分散性变差。此方法的建立为加氢催化剂表面金属分散状态与催化性能的关系研究提供了新方法。

Based on the simplified Kerkhof-Moulijn model,a method has been established to investigate the dispersion state of active metal in hydrogenation catalyst on the carrier using the quantitative results of X-ray photoelectron spectroscopy(XPS).The model has fully considered the influence of the specific surface area of the carrier,carrier true density and the mean free path of photoelectrons on the quantitative results of XPS.In line with the atomic molar ratio of catalyst surface active metal to the carrier obtained by XPS analysis,the apparent particle size of active metal on carrier surface can be obtained to analyze the dispersion state of active metal more intuitively and objectively.In addition,a study has been conducted on the effects of the active metal load,specific surface area of the carrier and the type of metals on the dispersion states and a comparison has been performed on the dispersion differences of hydrogenation catalysts before and after sulfurization.The results show that the sulfurization process leads to the reduction of dispersivity for metal elements.This method can provide a new way for the research of the correlation between the state of metal dispersion on the surface of hydrogenation catalyst and the catalytic performance.