Activity Test and Mechanism Study of 3DOM Ce0.8M0.1Zr0.1O2 (M=Cr, Sn, Fe, Co, Ni, Mn, Cu) Catalyst in the Selective Catalytic Reduction of NO by CO**

A series of three-dimensionally ordered macroporous (3DOM) Ce0.8M0.1Zr0.1O2(M=Cr, Sn, Fe, Co, Ni, Mn, Cu) catalysts are synthesized and used in CO selective catalytic reduction of NOx. The results show that the NO conversion rate of 3DOM Ce0.8Cu0.1Zr0.1O2 catalyst at a lower temperature (150 degrees C) is close to 60 %. Besides, 3DOM Ce0.8Cu0.1Zr0.1O2 kept a stable NO removal efficiency within a wide range of gas hourly space velocity (GHSV) and long reaction time and exhibited remarkable resistance to H2O and SO2 poisoning, both individually and simultaneously. At the same time, the formation of the 3DOM structure not only improves the reduction performance and surface active sites of the catalyst, but also forms more oxygen defects and Ce3+ in the catalyst due to the strong synergistic effect of metal ions and ceria, which improves the surface oxygen concentration of the composite oxide catalyst and further improves the catalytic activity. In addition, the doping of copper ions on the surface of the 3DOM Cu-CZ catalyst can improve the activity of the catalyst and it can get trapped by CO to form Cu+-CO, which plays an important role in the NO+CO reaction at low temperature. The existence of oxygen vacancy at high temperature is beneficial to the activation of O-2 and the dissociation of NO in the process of CO oxidation. The reaction of NO+CO over 3DOM Cu-CZ catalyst follows L-H and E-R mechanism respectively.

Automated summary

The 3DOM Ce0.8Cu0.1Zr0.1O2 catalyst shows good NO conversion performance at low temperatures, with resistance to H2O and SO2 poisoning, and the formation of more oxygen defects and Ce3+ which enhances catalytic activity. Additionally, doping with copper ions improves surface activity of the catalyst.