Abstract:
A series of Mn and Fe metal oxide catalysts loaded onto USY, as well as single metal oxides, were prepared and characterized. The effects of interactions between the catalytic components and the introduction of gas phase NO on the catalytic ozonation of toluene were investigated. Characterization showed that there existed strong interactions between MnOx, FeOx, and USY, which enhanced the content of oxygen vacancies and acid sites of the catalysts and thus boosted the generation of reactive oxygen species and the adsorption of toluene. The MnFeOx-USY catalyst with MnOx and FeOx dimetallic oxides exhibited the most excellent performance of catalytic ozonation of toluene. On the other hand, the presence of NOx in reaction gas mixtures significantly promoted both toluene conversion and mineralization, which was attributed to the formation of nitrate species on the catalysts surface and thus the increase of both acid sites and toluene oxidation sites. Meanwhile, the reaction mechanism between O3 and C7H8 was modified in which the strong interactions between MnOx, FeOx, and USY accelerated the reaction progress based on the L-H route. In addition, the formation of the surface nitrate species not only promoted reaction progress following the L-H route but also resulted in the occurrence of the reaction via the E-R route.
摘要:
一系列负载到USY上的Mn和Fe金属氧化物催化剂,以及单一金属氧化物,准备和表征。研究了催化组分之间的相互作用和气相NO的引入对甲苯催化臭氧化的影响。表征表明,MnOx之间存在较强的相互作用,FeOx,使用,提高了催化剂的氧空位和酸性位点的含量,从而促进了活性氧的产生和甲苯的吸附。含有MnOx和FeOx二金属氧化物的MnFeOx-USY催化剂表现出最优异的甲苯催化臭氧化性能。另一方面,反应气体混合物中NOx的存在显着促进了甲苯转化和矿化,这归因于在催化剂表面上形成硝酸盐物种,从而增加了酸位点和甲苯氧化位点。同时,O3和C7H8之间的反应机理被修改,其中MnOx之间的强相互作用,FeOx,和USY加速了基于L-H路线的反应进程。此外,表面硝酸盐物种的形成不仅促进了L-H途径之后的反应进程,而且导致了通过E-R途径的反应的发生。