过渡金属对选择性催化还原脱硝CeO2@TiO2催化剂低温活性的促进作用

Promoting effect of transition metal on low-temperature deNOx activity of CeO2@TiO2 catalyst for selective catalytic reduction

  • 摘要: 采用过渡金属MM=Mn、Co、Fe和Cu)掺杂改性自发沉积策略制备的非晶态CeO2@TiO2催化剂,考察M-CeO2@TiO2选择性催化还原NOx的低温活性,并通过XRD、TEM、N2吸附-脱附、H2-TPR、NH3-TPD及in-situ FT-IR等表征手段研究M-CeO2@TiO2的结构、表面性质以及低温NH3-SCR反应过程。结果表明,M-CeO2@TiO2具有更优异的低温氧化还原能力以及更多的表面酸量,且Cu掺杂对CeO2@TiO2选择性催化还原NOx低温活性具有最为显著的促进作用。Cu-CeO2@TiO2催化剂在低温NH3-SCR反应过程中同时存在E-R机理和L-H机理,但是由于"快速SCR"使得L-H机理反应起关键作用。

     

    Abstract: Transition metal M(M=Mn, Co, Fe and Cu) modified amorphous CeO2@TiO2 catalysts were prepared via a spontaneous deposition strategy. The low-temperature deNOx activity of M-CeO2@TiO2 for selective catalytic reduction was investigated. XRD, TEM, N2 adsorption-desorption, H2-TPR, NH3-TPD and in-situ FT-IR were used to study the structure, surface property and low-temperature NH3-SCR reaction performance of M-CeO2@TiO2. The results showed that the M-CeO2@TiO2 had better low-temperature oxidation reducibility and more surface acid. Cu doping had the most significant promoting effect on low-temperature deNOx activity for selective catalytic reduction. During the low-temperature NH3-SCR reaction, both the L-H and E-R mechanisms existed over the Cu-CeO2@TiO2 and the L-H mechanism could play a pivotal role due to the "fast SCR"process.

     

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