Nitric Acid → Cerium nitrate

Participants

Reaction Steps

A quantity of 700 grams of gamma alumina powder having a surface area of 150 square meters per gram (150 m2 /g) was impregnated with an aqueous palladium nitrate solution containing 31.9 grams of palladium. All 31.9 grams of palladium were impregnated. The palladium containing alumina, a nitric acid stabilized colloidal dispersion of ceria containing 300 grams CeO2 (Note: The average CeO2 particle size is about 100 angstrom. This is not bulk ceria.), cerium nitrate crystals in an amount sufficient to form 500 grams CeO2,lanthanum nitrate crystals in an amount sufficient to form 100 grams La2O3, barium acetate crystals in an amount sufficient to form 60 grams BaO, zirconium acetate solution in an amount sufficient to form 140 grams ZrO2 and 500 grams of co-formed ceria-zirconia powder (surface area 50 m2 /g containing 20 wt % CeO2) were ballmilled with acetic acid to form a slurry. The slurry was further mixed with 70 grams of pre-milled NiO particles in water to form a washcoat layering slurry containing about 48 percent by weight of solids. A monolith support of cordierite containing about 400 flow passages per square inch of cross section was dipped into the washcoat slurry. The excess was blown off the monolith by compressed air. The resultant catalyzed monolith after being calcined at 450° C. contained 55 g/ft3 palladium, 0.7 g/in3 alumina, 0.8 g/in3CeO2, 0.1 g/in3La2O3, 0.14 g/in3ZrO2, 0.06 g/in3BaO, 0.5 g/in3 ceria-zirconia composite and 0.07 g/in3NiO.

Provenance & Evidence