Investigation Of Selective Catalytic Reduction Of NO With NH₃ Over The Metal-organic Framework ?Cu-MOF?

Nitrogen oxides (NOx) are the main pollutants in the atmosphere, which can trigger photochemical smog, ozone depletion and other serious pollution problems. At present, due to the fast expansion of China's industrial situation, the emission of NOx is continually increasing year by year. Now the emissions reduction and pollution prevention of NOx have become a hot issue in China. Selective catalytic reduction (SCR) of NOx with NH3 is the most widely used and most efficient denitration technique, in which the catalyst as the key factors determing the catalytic reaction efficiency. At present, metal organic framework compounds (MOFs) with regular channel structure, bigger specific surface area, and coordination of metal active sites have been widely used in catalysis. Although MOFs are rarely used in gas phase catalysis, they have been considered to be the promising catalysts in the field of denitrification. In this papaer, Cu3(BTC)2, Cu-Ag-BTC and Ag/Cu3(BTC)2 catalysts forNH3-SCR reaction were synthesized successfully. The physical and chemical properties of these catalysts were further investigated by a variety of characterization methods. The detail results of this research are as follows:(1) Cu3(BTC)2 catalyst was successfully prepared through electrochemical route. After systematically optimizing the reaction conditions such as solvents, voltage, concentration of the electrolyte and reaction time, pure Cu3(BTC)2 with high crystallinity was obtained in 97.2% yield. Thermal gravimetric analysis indicated that the framework was stable up to 310 ?. It is found that the activation temperature of the Cu3(BTC)2 shows a significant effect on the catalytic activity in NH3-SCR reaction. The Cu3(BTC)2 sample activated at 240 ? had the best catalytic activity and gave NO conversion of 90% at 220-280 ?. A reaction mechanism was proposed based on the in situ FTIR spectroscopy results.(2) The bimetallic Cu-Ag-BTC catalysts were successfully prepared by ion exchange method. The addition of noble metal ion did not change crystal structure of catalyst. In NH3-SCR recation, Cu-Ag-BTC catalyst with 10 wt% Ag content reached the removal denitrification efficiency of 92% after 230 ? activation.(3) Ag nanoparticles were successfully loaded on Cu3(BTC)2 catalyst using UV reduction method, Ag nanoparticles with spherical structure were dispersed on the surface of the skeleton structure of Cu3(BTC)2 highly. The synergistic effect of Cu3(BTC)2 and Ag nanoparticles can improve the denitrification efficiency. The Ag/Cu3(BTC)2 catalyst with 15 wt% amount exhibited NO conversion of 100% at 200-260 ?.