Mullite (3Al2O3·2SiO2) is light and inexpensive ceramic material which is highly regarded as a potential candidate for fabrication of diesel particulate filters (DPFs). Highly porous, needle-like (acicular) mullite structure is fully suitable for capturing and removal of harmful particulate matter (soot) from diesel engine exhaust causing minimal pressure drop which is extremely important for smooth engine operation. At the same time filter material is expected to catalyse combustion, i.e., oxidation of the captured soot to CO2 which is extremely important for providing a regular filter cleaning/regeneration. This project is focused on development of a simple, inexpensive and environmentally friendly method for production of porous, acicular mullite DPF material, containing in situ formed copper molybdate (Cu3Mo2O9) as a soot oxidation catalyst. A novel approach will use commercial powders of Al2O3, SiO2 and CuO and powder obtained by controlled oxidation of ground waste MoSi2 which appears to be the key material essential for developing needle-like microstructure as well as forming the soot oxidation catalyst. Namely, the controlled oxidation of pulverised MoSi2 yields MoO3 which promotes formation of needle-like microstructure and reacts with CuO creating Cu3Mo2O9 catalyst.
