Effects of the Extent of Silica Doping and the Mesopore Size of an Alumina Support on Activity as a Diesel Oxidation Catalyst

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• 作者：Junko Uchisawa ; Takeru Tango ; Alessio Caravella ; Shigeki Hara ; Masaaki Haneda ; Tatsuro Murakami ; Hideyuki Nakagawa ; Tetsuya Nanba ; Akira Obuchi
• 刊名：Industrial & Engineering Chemistry Research
• 出版年：2014
• 出版时间：May 14, 2014
• 年：2014
• 卷：53
• 期：19
• 页码：7992-7998
• 全文大小：504K
• 年卷期：v.53,no.19(May 14, 2014)
• ISSN：1520-5045

文摘

Both the extent of SiO₂ doping and the mesopore size of alumina were investigated with the aim of developing a support that maintains high activity during the catalytic oxidation of diesel exhaust hydrocarbons and NO over 0.75 wt % Pt/0.25 wt % Pd even after high temperature treatment. By controlling the SiO₂ doping ratio and heat treatment conditions during the preparation process, 24 types of SiO₂鈥揂l₂O₃ were obtained, with SiO₂ levels from 0 to 5.9 wt % and mesopore sizes from 6.7 to 10.2 nm. The highest catalytic activity was obtained at a SiO₂ loading of approximately 4 wt %, and the beneficial effects of SiO₂ doping were thought to result from optimization of the basicity of the support. Catalytic activity improved as the mesopore size increased up to approximately 10 nm. Computational simulations confirmed that the diffusion limitations of small mesopore structures may affect catalytic activity when the mesopores are below 10 nm.