NO在氧化铝负载的Pd催化剂上吸附的TPD-MS研究

The adsorption of NO on alumina supported Pd catalysts and the effect of adding Li 2O on NO adsorption have been investigated by using TPD MS method. Experimental results certify the existence of three types of surface species. The adsorptive dissociation of NO gives a relatively inactive intermediate N 2O. Its desorption amount is larger on Al 2O 3 and Pd/Al 2O 3 Li 2O than that on Pd/Al 2O 3. The adsorption intensity of N 2O is the strongest on Pd/Al 2O 3 Li 2O. The experiments of competitive adsorption of O 2 and NO reveal that the presence of O 2 has two effects: (1) the O atom sticks to the Pd site on the surface and inhibits the adsorption of NO, as well as the decomposition of NO; (2) O 2 can react with NO to form nitrite or nitrate species which can adsorb strongly on the surface. The relative efficiency of the two effects differs with temperature, and this can be applied to explain some phenomena in the adsorption of NO, and the selective catalytic reduction of NO as well.