LDH-derived preparation of CuMgFe layered double oxides for NH3-SCR and CO oxidation reactions: Performance study and synergistic mechanism

The NH3-SCR and CO oxidation reactions provides a promising route for the synergistic removal of NOx and CO. Herein, a novel two-dimensional CuMgFeO layered double oxides by the co-precipitation method and employed it for the NH3-SCR and CO oxidation reactions. The catalytic activity results showed that the CuMgFeO sample reached 96.8 % NO conversion at 250 degrees C, and 100 % CO conversion in temperature of 200-300 degrees C. Impressively, the CuMgFeO catalyst showed outstanding N2 selectivity, water resistance, and maintained splendid long-term catalytic stability. The superior NH3-SCR and CO oxidation activity of CuMgFeO catalyst can be related to the well dispersion of CuO species, higher reducibility, and abundance of acid sites. Meanwhile, XPS analysis indicated that the presence of electron transfer between the Cu2+ and Fe3+ redox cycles, as well as adsorbed oxygen on the sample surface were the main reactive oxygen species. The in situ DRIFT species indicate that the NH3-SCR reaction over CuMgFeO catalysts mainly complied with the E-R mechanism, while the CO oxidation followed the L-H mechanism. Finally, the deactivation mechanism of SO2 was investigated by in situ DRIFT species, indicating that SO2 hinders the NH3-SCR reaction through competition with NH3 and NOx for adsorption sites and the formation of ammonium sulfate salts. This work provides insight into the simultaneous implementation of the NH3-SCR and CO oxidation reactions on a single catalyst, which is of great value for the future synergistic control of flue gas pollutants.

Automated summary

A novel CuMgFeO layered double oxide catalyst was synthesized and employed for NH3-SCR and CO oxidation reactions. The catalyst exhibited excellent catalytic activity, selectivity, water resistance, and long-term stability, which could be attributed to the well dispersion of CuO species, higher reducibility, and abundance of acid sites. Furthermore, the research on the reaction mechanism revealed that NH3-SCR and CO oxidation reactions followed different mechanisms.