【摘要】：為了排除載體孔結(jié)構(gòu)變化對催化性能的影響,研究了二氧化鈦改性α-氧化鋁載體對銀催化劑催化乙烯環(huán)氧化反應性能的影響。研究結(jié)果表明,二氧化鈦表面改性α-氧化鋁載體對載體的比表面積、孔結(jié)構(gòu)無明顯影響;載體表面改性導致催化活性組分銀在載體表面均勻分散,分散狀況明顯改善;經(jīng)二氧化鈦改性后載體表面與銀的相互作用增強;對單負載銀催化劑,由改性載體制備的銀催化劑的活性和選擇性均下降,改性對催化性能明顯不利;對于共浸漬法制備的多組分銀催化劑,低溫焙燒對催化性能不利,而由經(jīng)1000℃高溫焙燒的二氧化鈦改性載體制備的銀催化劑的催化活性明顯提高。研究表明,載體表面等電點降低及其與銀的強相互作用是造成催化劑上金屬銀良好分散的主要原因;此外,銀催化劑助劑的存在減弱了二氧化鈦改性載體與銀之間的強相互作用、抑制了環(huán)氧乙烷(EO)深度反應的活性,兩者協(xié)同作用提升了多組分銀催化劑的催化反應性能。
[Abstract]:In order to eliminate the effect of pore structure on the catalytic performance, the effect of titanium dioxide modified 偽-alumina support on the epoxy oxidation of ethylene catalyzed by silver catalyst was studied. The results show that the surface modification of titanium dioxide 偽-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，

本文編號：2496727