Patent ID: 8075859

Claim:
A process for reducing nitrogen oxides in a waste stream, the process comprising the step of: contacting a waste stream containing nitrogen oxides with a catalyst, the catalyst comprising: (A) a nanocomposite particle, the nanocomposite particle comprising: (i) titanium dioxide nanoparticles wherein the titanium dioxide nanoparticles are predominantly anatase; (ii) metal oxide nanoparticles selected from the group consisting of zirconium dioxide, cerium dioxide, hafnium oxide, tin oxide, niobium oxide and tantalum oxide; and (iii) a surface stabilizer selected from the group consisting of silicon dioxide, aluminum oxide, phosphorus pentoxide, aluminum silicate and aluminum phosphate, wherein the metal oxide nanoparticles are formed by hydrothermally treating an amorphous hydrated metal oxide in the presence of the titanium dioxide nanoparticles; and (B) at least one metal component, the at least one metal component comprising: a metal selected from the group consisting of platinum, gold, silver, palladium, copper, tungsten, molybdenum, vanadium, iron, rhodium, nickel, manganese, chromium, cobalt, and ruthenium with the result that the amount of nitrogen oxides in the waste stream is reduced.