Fe–Ti spinel for the selective catalytic reduction of NO with NH3: Mechanism and structure–activity relationship
Fe–Ti spinel for the selective catalytic reduction of NO with NH3: Mechanism and structure–activity relationship
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DOI：
10.1016/j.apcatb.2012.01.001
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发表时间：
2012-05
影响因子：
22.1
通讯作者：
Shijian Yang;Junhua Li;Chizhong Wang;Jinghuan Chen;Lei Ma;Huazhen Chang;Liang-Fu Chen;Yue Peng
中科院分区：
文献类型：
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作者：
Shijian Yang;Junhua Li;Chizhong Wang;Jinghuan Chen;Lei Ma;Huazhen Chang;Liang-Fu Chen;Yue Peng
采用共沉淀法合成了一系列非化学计量比的Fe-Ti尖晶石（Fe 3 −xTix）1−δ O 4，并将其用于NH3选择性催化还原（SCR）NO反应。Ti的引入抑制了（Fe 3 −xTix）1−δ O 4上的Langmuir-Hinshelwood反应机理。因此，在150-250°C下，（Fe 3 −xTix）1−δ O 4（x ≤ 0）的SCR活性低于γ-Fe 2 O3。然而，由于Ti的掺入，通过Eley-Rideal机理促进了（Fe 3 −xTix）1−δ O 4上的SCR反应。（Fe 3-xTix）1-δ O 4（x <$0）的SCR活性主要与表面Fe 3+的氧化能力、表面吸附的NH3浓度和表面可还原的Fe 3+浓度有关。Ti的引入虽然降低了表面Fe ~（3+）的氧化能力，但增加了表面吸附的NH ~（3+）浓度和表面可还原的Fe ~（3+）浓度。结果表明，（Fe 2 Ti）0.8O4在300-400°C范围内具有优异的SCR反应活性、选择性和H2O/SO2耐受性。
A series of non-stoichiometric Fe–Ti spinel (Fe3−xTix)1−δO4were synthesized using a co-precipitation method and then developed as environmental-friendly and low cost catalysts for the selective catalytic reduction (SCR) of NO with NH3. As Ti was incorporated into γ-Fe2O3, the SCR reaction over (Fe3−xTix)1−δO4through the Langmuir–Hinshelwood mechanism was restrained. Therefore, the SCR activity of (Fe3−xTix)1−δO4(x≠0) was less than that of γ-Fe2O3at 150–250°C. However, the SCR reaction over (Fe3−xTix)1−δO4through the Eley–Rideal mechanism was promoted due to the incorporation of Ti. The SCR activity of (Fe3−xTix)1−δO4(x≠0) was mainly related to the oxidative ability of Fe3+cation on the surface, the concentration of NH3adsorbed on the surface and the concentration of reducible Fe3+cation on the surface. Although the oxidative ability of Fe3+cation on the surface decreased due to the incorporation of Ti into γ-Fe2O3, the concentration of NH3adsorbed on the surface and the concentration of reducible Fe3+cation on the surface both increased. As a result, (Fe2Ti)0.8O4showed excellent activity, selectivity, and H2O/SO2durability for the SCR reaction at 300–400°C.