Ce对CoMnOx催化剂协同CO/NH3脱硝性能

The emission of CO and NOx in sintering flue gas is the focus of current air pollution control. However, the traditional NH3-SCRtechnology has problems such as unmatched flue gas temperature, uneconomical CO treatment, and serious ammonia slip. In order to explore the law of CO assisted NH3-SCR denitrification technology, a series of de-NOx catalysts with CoMnCe as the active component weredeveloped by coprecipitation method. CO in the sintering flue gas can be used to synergize NH3 to remove NOx, which can improve the utilization of CO in the flue gas and reduce the use of NH3. The performance test results show that when Ce molar ratio is 0.75, the catalystexhibits the best synergistic NOx removal efficiency, and the NO conversion efficiency is up to 98% at 125 ℃ . The characterization resultsof XRD, Raman, XPS, TEM, H2-TPR, etc. indicate that the increase of Ce molar ratio in the catalyst inhibits the growth of the grains inCo3O4. Although Co3O4 and CeO2 still maintain the original lattice structure, there are still some Co or Mn atoms doped with Ce atoms,resulting in the distortion of the metal lattice, the formation of defect structures on the catalyst surface, and the generation of a large number of oxygen vacancies. At the same time, when the Ce molar ratio is relatively large, the catalyst surface structure is blocked byCeO2. Moreover, the excess CeO2 agglomerates on the catalyst surface,preventing Mn and Co species from participating in the catalytic reaction. The catalytic activity test finds that the prepared catalyst shows a certain anti oxygen inhibition ability, especially when the mole ratio of Ce is relatively low, the CO-SCR reaction activity is better at low temperature, and the anti-oxygen inhibition ability of the catalystdecreases with the increase of the mole ratio of Ce. At the same time, with the increase of temperature, the surface oxygen flows faster onthe catalyst surface, thus promoting the reaction. At this time, the CMC2 catalyst with more Ce shows the best anti oxygen inhibition performance, and the NH3 - SCR denitrification activity is reduced by CO. However, its synergistic denitrification efficiency for theCMC0.75 catalystis still high at relatively low temperature, which may be due to the high oxidation capacity of the Co, Mn and Ce metaloxides contained in the catalyst, Therefore, reasonable control of the proportion and distribution of different metals can improve the oxidation capacity of the catalyst surface, enhance the flow of surface oxygen and the synergistic catalytic activity.