Effect of water vapour and SO2 addition on stability of zirconia-pillared montmorillonites in selective catalytic reduction of NO with ammonia

A series of acid-treated zirconia-pillared montmorillonites doped with carb on and manganese was studied in selective catalytic reduction (SCR) of NO w ith NH3. For selected catalysts, various stability tests were performed. Ca talysts M2C and M2CMn14 showed very good stability in long-run tests with t he use of a standard reaction mixture. Addition of water vapour caused smal l decrease in NO conversion but the effect was reversible. SO2 poisoning ga ve different results depending on the applied method. In the conditions wel l-simulating DENOX process, i.e, when SO2 was added in the course of cataly tic reaction, the activity of the studied catalysts did not change. (C) 200 1 Elsevier Science B,V. All rights reserved.