Role of CTAB in the improved H2O resistance for selective catalytic reduction of NO with NH3 over iron titanium catalyst
Role of CTAB in the improved H2O resistance for selective catalytic reduction of NO with NH3 over iron titanium catalyst
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DOI：
10.1016/j.cej.2018.04.107
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发表时间：
2018-09-01
影响因子：
15.1
通讯作者：
Huang, Zhanggen
中科院分区：
文献类型：
--
作者：
Li, Yulin;Han, Xiaojin;Huang, Zhanggen
采用十六烷基三甲基溴化铵(CTAB)辅助法制备了均匀介孔铁钛(CT-FeTi)催化剂，在低温NH3选择性催化还原(SCR)NO反应中表现出良好的催化活性和耐水性能。通过BET、TPD、TPSR和原位漂移等测试手段，揭示了H2O对SCR反应的抑制机理，并探讨了CTAB在低温SCR过程中提高抗H2O性能中的作用。结果表明，H2O抑制了NO在CT-FeTi催化剂表面的吸附，并抑制了Fe3++NH3->反应生成的中间物种(-NH2)的生成，Fe2+-NH2+H+CTAB起到了“结构”和“化学”的促进作用，不仅优化了催化剂的孔径，避免了H2O的过度放大，而且促进了桥联硝酸盐和NH3物种在Lewis酸位上的吸附，从而提高了催化剂的活性和抗H2O性能。
Uniform mesoporous iron titanium (CT-FeTi) catalysts were synthesized by a CTAB-assisted process and exhibited good catalytic activity and H2O resistance when tested in the selective catalytic reduction (SCR) of NO with NH3 at low temperature. BET, TPD, TPSR and in situ DRIFTS were carried out to reveal the inhibition mechanism of H2O on SCR reaction and determine the role of CTAB in the improved H2O resistance during low-temperature SCR processes. Results showed that H2O inhibited the adsorption of NO on the surface of CT-FeTi catalysts, as well as the formation of the intermediate species (-NH2), which was produced by the reaction Fe3+ + NH3 -> Fe2+-NH2 + H+ CTAB acted as a "structural" and "chemical" promoter, not only optimizing the pore size to avoid being excessively enlarged in the presence of H2O, but also enhancing the adsorption of bridging nitrate and NH3 species on Lewis acid sites, thus improving the catalytic activity and H2O resistance.