The reduction of NO by hydrocarbons over PdCo/ZSM-5:: The components of the catalyst and their role in the process

A PdCoZSM-5 catalyst was prepared by ion-exchange and impregnation. In such a catalyst besides CO2+ ions, PdO and CO3O4 are formed while a catalyst is pre-treated in flowing air 770 K. Catalytic runs of deNOx reaction were performed in a flow system. Temperature programmed surface reaction (TPSR) of NO, O-2, CH4 show three functions of our PdCoZSM-5 catalyst: oxidation of NO to NO2 over Co3O4, methane activation and oxidation by NO2 to methanol over PdO, and finally the reduction of nitrogen oxides by methanol. The catalyst works efficiently if the temperature windows of each needed function overlap enough.