ISOTHERMAL OSCILLATIONS IN THE CATALYTIC DECOMPOSITION OF NITROUS-OXIDE OVER CU-ZSM-5

The catalytic decomposition of nitrous oxide was studied on a copper-exchanged ZSM-5 catalyst in the temperature range 648-723 K. Using a mixture of 1000 ppm N2O in nitrogen, isothermal oscillations both in nitrous oxide and oxygen concentrations occurred, accompanied by formation of small amounts of NO. While the addition of excess oxygen did not significantly change frequency and amplitude of the oscillations, even the presence of small amounts of NO immediately quenched the oscillations. The reacting system then remained in the ignited state at high nitrous oxide conversions.