Mn掺杂提升CeTiO_(x)催化剂定向氧化NO机制研究

Mechanism Study of Mn-doping to Promote the Directional O_(x)idation of NO over CeTiO_(x) Catalyst

氮氧化物的大量排放对环境和人体造成了严重危害,而目前低温烟气领域的氮氧化物处理技术依然亟待开发。本研究通过共沉淀法合成Mn掺杂CeTiO_(x)的MnCeTiO_(x)催化剂,用于在低温条件下催化臭氧和过氧化氢定价氧化NO为NO_(2),以便后续实现同步脱硫脱硝。研究结果表明,Mn掺杂后,Mn和Ce、Ti之间的电子协同作用增强了催化剂表面的氧化还原性,提高了其催化O_(3)和H_(2)O_(2)产生自由基的能力,从而可以增强其定价氧化NO为NO_(2)的催化活性。当O_(3)和NO浓度比为0.4、H_(2)O_(2)和NO浓度比为0.8、140℃时,Mn_(0.25)CeTiO_(x)催化剂定价氧化NO为NO_(2)的效率可以达到83%。

The massive emission of nitrogen oxides has caused serious harm to the environment and human beings,but the treatment technology of nitrogen oxides in the low-temperature flue gas still needs to be developed urgently.In this study,Mn-doped CeTiO_(x)(MnCeTiO_(x))catalysts were synthesized by a simple co-precipitation method,which was adopted as catalysts for NO oxidation to NO_(2) by ozone and hydrogen peroxide at low temperature,so as to achieve synchronous desulfurization and denitrification in the following steps.The results show that after Mn doping,the electron synergism between Mn,Ce and Ti enhances the surface oxidation-reduction property of catalyst,which could promote the activation of O_(3) and H_(2)O_(2) to free radicals on catalyst surface,thereby enhancing the catalytic activity for converting NO to NO_(2).When the concentration ratio of O_(3) to NO is set to 0.4,and that of H_(2)O_(2) to NO is 0.8,83%of NO could be oxidized to NO_(2) on Mn_(0.25)CeTiO_(x) catalyst at 140℃.