Ordered micro/macro porous K-OMS-2/SiO nanocatalysts: Facile synthesis, low cost and high catalytic activity for diesel soot combustion.

A series of novel oxide catalysts, which contain three-dimensionally ordered macroporous (3DOM) and microporous structure, were firstly designed and successfully synthesized by simple method. In the as-prepared catalysts, 3DOM SiO is used as support and microporous K-OMS-2 oxide nanoparticles are supported on the wall of SiO. 3DOM K-OMS-2/SiO oxide catalysts were firstly used in soot particle oxidation reaction and they show very high catalytic activities. The high activities of K-OMS-2/SiO oxide catalysts can be assigned to three possible reasons: macroporous effect of 3DOM structure for improving contact between soot and catalyst, microporous effect of K-OMS-2 for adsorption of small gas molecules and interaction of K and Mn for activation of gas molecules. The catalytic activities of catalysts are comparable to or even higher than noble metal catalyst in the medium and high temperature range. For example, the T of K-OMS-2/SiO-50, 328 °C, is much lower than those of Pt/AlO and 3DOM Au/LaFeO, 464 and 356 °C,respectively. Moreover, catalysts exhibited high catalytic stability. It is attributed to that the K ions are introduced into the microporous structure of OMS-2 and stabilized in the catalytic reaction. Meanwhile, the K ions play an important role in templating and stabilizing the tunneled framework of OMS-2.