Decomposition of no over Cu-ZSM-5 prepared by solid-state ion exchange

Cu, H-ZSM-5 (Cu/H=1.5) prepared by solid-state ion exchange with excess CuCl proved to be, after reduction with CO at 500°C, highly active in NO decomposition even at reaction temperatures below 300°C, while reduction with hydrogen resulted in a catalyst which was much less active below 450°C but highly active at about 500°C. These phenomena are interpreted in terms of the role of Cu+ lattice cations and Brönsted acid sites involved in the mechanism of the catalytic reaction.