CATALYTIC DECOMPOSITION OF NITROUS-OXIDE ON ALUMINA-SUPPORTED RUTHENIUM CATALYSTS RU AL2O3/

The catalytic decomposition of N2O (28 mol%) has been studied for the Ru/Al2O3 system with various ruthenium contents (Ru wt% = 0.00-0.26). The optimized catalyst of the studied system has a high catalytic acti vity of 4.8 x 10(4) mu mol (N2O) g(-1) h(-1) at 400 degrees C. The stu dy shows that the surface area of Ru/Al2O3 decreases with increase of loading of the metal. Two different types of surface structure are for med, and the optimized catalyst is found in the intermediate region be tween them. The catalyst has been investigated further with various ba ckground gases (O-2, CO2, and H2O). It is found that O-2 has little in hibitive effect on the high conversion rate reaction while it shows a certain effect at low conversion (low temperature). Acidity-basicity o f the catalyst has been examined with the probe gas CO2. In contrast t o CO2, which does not adsorb on the catalyst, water shows a strong ten dency to hamper the decomposition. The reaction on the optimized catal yst can be described as first order with respect to N2O partial pressu re. Using the findings of this work, a two-step process has been propo sed for the adipic acid off-gas treatment.