Highly Porous Ceramic Materials Based on Coarse-Dispersed αAl₂O₃

Synthesis of highly porous ceramic materials for catalytic converters based on coarse-dispersed αAl₂O₃ using a combination of compaction and thermochemical synthesis with the participation of active ultrafine binders is carried out. Using X-ray diffraction analysis (XRD) and scanning electron microscopy (SEM), it is established that the morphology of the synthesized material simultaneously includes large pores between filler particles (dominant αAl₂O₃ phase) and submicron pores in transboundary regions that appeared during the processes of liquid-phase sintering and gas evolution. A significant amount of indialite (Mg₂Al₄Si₅O₁₈) and spinel (MgAl₂O₄) formed as a result of thermochemical synthesis on surfaces and in the gaps between coarse-dispersed particles is revealed. The dominant pore size (according to the volume of mercury intrusion) is from 20 to 60 μm (about 73%), as well as pores with size from 0.4 to 2 μm (about 6%).The average pore size is about 9 μm. Highly porous materials with these characteristics of the pore space can be effectively used after modification as catalytic converters for the dehydrogenation of alkyl aromatic hydrocarbons with large molecular sizes (about 400 nm) with a long mean free path on the order of ~3–4 μm.