Promotive effect of additives to In/H-ZSM-5 catalyst for selective reduction of nitric oxide with methane in the presence of water vapor

摘要

It has been found that Ga and In/H-ZSM-5 are active catalysts for selective NO reduction with methane, while the activities are retarded by water vapor, which particularly retards the oxidation of NO to NO_2 on zeolitic Lewis acid sites, a necessary step for the reduction of NO with methane. In order to attain a H_2O-tolerant catalyst based on In/H-ZSM-5, the substitute for Lewis acid sites was searched. After testing several metal species, it was found that In/H-ZSM-5 loading Pt, Rh and Ir exhibited high catalytic activity for NO reduction even in the presence of H_2O.