Study On The Preparation And Catalytic Reaction Mechanism Of Low Temperature SCR Trefoil Catalyst

Nitrogen oxides (NOx) is one of the main pollutants in the atmosphere, and NH3-SCR, which used NH3 as the reductant, is the most widely used technology for NOx removal.In this paper, we prepared trefoil catalysis particles using ammonium metavanadate (analytically pure), titanium dioxide (anatase) as the main material, we investigate the influence of calcination temperature on the catalytic activity and the compressive mechanical strength by changing the calcination temperature. The results show that when the calcination temperature is 450 ?, the sample has the best catalytic activity and compressive mechanical strength.The catalytic reaction mechanism was studied by DRIFTS. The results show that under low temperature, NH3 is mainly adsorbed on Br(?)nsted and Lewis acid sites on the surface of the catalyst; the adsorption of NO+O2can be divided into bidentate nitrate, (N2O2)2-,monodentate nitrate, nitrite, nitro-bridge species and adsorbed NO2on the surface, but compared to the adsorption of NH3, the adsorption amount of NO+O2 is less. The gas phase or weak adsorption of N02 is the main reaction pathway of NO. Compared to Lewis acid sites, Bronsted acid sites are more likely to participate in the reaction, the reaction followed L-H mechanism at low temperature.We investigate the effects of drying temperature and drying time on the catalytic activity and the compressive mechanical strength by changing the drying temperature and drying time.. By optimizing the catalyst forming formula, we find the best dosage of H3BO3+SiO2, and test the H2O and SO2 resistance of the catalyst samples under the optimum conditions. The results show that when the drying temperature is 80 ? and the drying time is 0.5 h, the catalyst samples have the best catalytic activity and compressive mechanical strength. When the adding H3BO3+SiO2 content is 7.5%, the catalyst has the best compressive mechanical strength and stability.