The beneficial effect of halloysite nanotubes as a matrix preventing the break of ordered mesoporous silica structure under microwave-assisted metal deposition

Abstract

The influence of microwave treatment on the structural characteristics of MCM-41 silica-based supports and properties of Ru-containing catalysts prepared thereon was investigated. The 800 W and 20 min mode of microwave treatment inevitably destroyed MCM-41 silica structure during the deposition of ruthenium particles. When moderate irradiation power to 400 W and duration time to 10 min, the destruction of the support was partially prevented, but the ruthenium loading reduces, simultaneously. To reinforce MCM-41 silica halloysite nanotubes (Hal) were introduced as a matrix for templated self-assembly of mesoporous silica, thereby forming ordered hierarchical MCM-41/Hal composite. The beneficial effect of Hal on the structural properties and stability of MCM-41 support under microwave-assisted Ru impregnation was demonstrated. MCM-41/Hal-supported catalysts revealed enhanced textural properties and characteristics of active component (high metal loading, narrow particle size distribution, high dispersion) compared to the analogous based on pure MCM-41. The catalytic properties were estimated in hydrogenation of multi-component aromatics-containing model feed, and Ru/MCM-41/Hal catalyst reveals 100 % benzene and ca. 89–90 % ethylbenzene and toluene conversion at the temperature range of 100–150°С for 3 h.