Abstract: A catalyst support structure for use as either a NOx catalyst support or as a DPF including (i) a multicellular ceramic body, preferably a monolithic ceramic honeycomb composed e.g., of cordierite or aluminum titanate, and (ii) a hydrophobic coating on at least the exterior surface thereof which results in a ceramic honeycomb exhibiting reduced or low absorption when exposed to both liquid catalytic coating media and aqueous media utilized in the process of applying the catalytic coating. In a preferred embodiment the hydrophobic coating is formed within or on an applied external skin layer provided on the multicellular ceramic body.