Patent ID: 7235507

Claim:
A diesel oxidation catalyst comprising a honeycomb substrate with a washcoat and a precious metal catalyst and a sulfur oxidation suppressant, wherein: (a) said honeycomb substrate is cordierite, mullite, silicon carbide, alumina, titania, zirconia, silica, alumina-silica, alumina-zirconia, stainless steel, Fe—Cr—Al alloy and the combinations thereof; (b) said washcoat is a mixture of: (i) from about 50 wt % to about 100 wt % of an acid-leached bentonite; (ii) from about 0 wt % to about 50 wt % of a refractory oxide, selected from titania, zirconia and combinations thereof; and, (iii) from about 0 wt % to about 50 wt % of a zeolite, selected from the group consisting of beta-zeolite, Y-zeolites, ZSM-5, mordenite, zeolites having a silica-to-alumina ratio of from about 5 to about 250, and combinations thereof, (c) said precious metal catalyst is selected from the group consisting of platinum, palladium, rhodium and combinations thereof, and (d) said sulfur oxidation suppressant selected from the group consisting of vanadium, chromium, bismuth, tin and combinations thereof.