二氧化钛改性α-氧化铝载体对银催化剂催化乙烯环氧化反应性能的影响
发布时间：2019-06-10 20:59
【摘要】：为了排除载体孔结构变化对催化性能的影响,研究了二氧化钛改性α-氧化铝载体对银催化剂催化乙烯环氧化反应性能的影响。研究结果表明,二氧化钛表面改性α-氧化铝载体对载体的比表面积、孔结构无明显影响;载体表面改性导致催化活性组分银在载体表面均匀分散,分散状况明显改善;经二氧化钛改性后载体表面与银的相互作用增强;对单负载银催化剂,由改性载体制备的银催化剂的活性和选择性均下降,改性对催化性能明显不利;对于共浸渍法制备的多组分银催化剂,低温焙烧对催化性能不利,而由经1000℃高温焙烧的二氧化钛改性载体制备的银催化剂的催化活性明显提高。研究表明,载体表面等电点降低及其与银的强相互作用是造成催化剂上金属银良好分散的主要原因;此外,银催化剂助剂的存在减弱了二氧化钛改性载体与银之间的强相互作用、抑制了环氧乙烷(EO)深度反应的活性,两者协同作用提升了多组分银催化剂的催化反应性能。
[Abstract]:In order to eliminate the effect of pore structure on the catalytic performance, the effect of titanium dioxide modified 伪-alumina support on the epoxy oxidation of ethylene catalyzed by silver catalyst was studied. The results show that the surface modification of titanium dioxide 伪-alumina carrier has no obvious effect on the specific surface area and pore structure of the carrier, and the surface modification of the carrier leads to the uniform dispersion of silver on the surface of the carrier, and the dispersion of silver is obviously improved. The interaction between the surface of the support and silver was enhanced after modification by titanium dioxide, and the activity and selectivity of the silver catalyst prepared from the modified carrier decreased for the single loaded silver catalyst, which was obviously disadvantageous to the catalytic performance. For the multi-component silver catalyst prepared by co-impregnation method, low temperature calcination is unfavorable to the catalytic performance, but the catalytic activity of the silver catalyst prepared from titanium dioxide modified support calcined at 1000 鈩，
本文编号：2496727
[Abstract]:In order to eliminate the effect of pore structure on the catalytic performance, the effect of titanium dioxide modified 伪-alumina support on the epoxy oxidation of ethylene catalyzed by silver catalyst was studied. The results show that the surface modification of titanium dioxide 伪-alumina carrier has no obvious effect on the specific surface area and pore structure of the carrier, and the surface modification of the carrier leads to the uniform dispersion of silver on the surface of the carrier, and the dispersion of silver is obviously improved. The interaction between the surface of the support and silver was enhanced after modification by titanium dioxide, and the activity and selectivity of the silver catalyst prepared from the modified carrier decreased for the single loaded silver catalyst, which was obviously disadvantageous to the catalytic performance. For the multi-component silver catalyst prepared by co-impregnation method, low temperature calcination is unfavorable to the catalytic performance, but the catalytic activity of the silver catalyst prepared from titanium dioxide modified support calcined at 1000 鈩，
本文编号：2496727
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