Methods of making a filter apparatus includes the step of creating a filter stack by axially spacing the porous ceramic plates from one another with a plurality of compliant spacers. In another example, the method includes the step of firing the first filter stack to sinter bond the first plurality of porous ceramic plates together with a first spacing element. In another example, the plurality of plates comprise a composition including catalyst particles and a binder material and the plates are fired to form porous plates without sintering a substantial amount of the catalyst particles. Methods of fabricating a porous ceramic article also include providing a porous substrate with a first material composition including mullite and infiltrating the pores of the substrate with a second material composition including cordierite. The method further includes the step of firing the first composition and the second composition to form the porous ceramic article.