Remarkable difference between the kinetic parameters of a selective catalytic reduction of NO by ethene on a copper ion-exchanged MFI zeolite and Al2O3

The kinetic parameters have been determined in reaction systems of NO+O-2+C2H4, NO2+O-2+C2H4, NO+O-2, and O-2+C2H4 over a copper ion-exchanged MFI zeolite (Cu-MFI) and Al2O3. The rate equations for the N-2 formation in the NO+O-2+C2H4 system on Cu-MFI (553-593 K) and Al2O3 (673-773 K) were expressed by rN(2)=kP(NO)(2.0)P(O2)(0.6)P(C2H4)(-1.0) exp(-168000/RT) and r(N2)=kP(NO)(1.1)P(O2)(0.5)P(C2H4)(0.1) exp(-294000/RT), respectively. The significant difference between the equations reveals that the reaction mechanisms or rate-determining steps on Cu-MFI and Al2O3 greatly differ. Ln addition, the rate equations for N-2 and CO2 production were the same on Cu-MFI, while they were different on Al2O3. The reaction mechanism is discussed based on the equations.