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METHODS FOR SELECTIVE CATALYTIC REDUCTION USING DOPED CERIUM (IV) OXIDES
METHODS FOR SELECTIVE CATALYTIC REDUCTION USING DOPED CERIUM (IV) OXIDES
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机译:掺杂铈(IV)氧化物选择性催化还原的方法
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摘要
Niobia- and tantala-doped ceria catalysts, their use in selective catalytic reduction (SCR) processes, and a compact after-treatment system for exhaust gases are disclosed. In some aspects, the catalyst comprises at least 91 wt. % of ceria and 0.1 to 9 wt. % of niobia or tantala doped on the ceria. While conventional SCR catalysts can deactivate at higher temperatures, the doped cerias, particularly ones having as little as 1 or 2 wt. % of Nb2O5 or Ta2O5, are activated toward NOx conversion by calcination. The doped cerias are also valuable for SCRF® catalyzed filter applications, including an after-treatment system that comprises a diesel particulate filter having inlets and outlets, and a dual-function catalyst coated on the inlets, outlets, or both. Compared with conventional SCR catalysts, the niobia or tantala-doped cerias enable a higher level of NO2 to be present.
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机译:公开了掺杂铌和钽的二氧化铈催化剂,它们在选择性催化还原(SCR)工艺中的用途以及用于废气的紧凑的后处理系统。在一些方面,所述催化剂包含至少91重量%。氧化铈的重量百分比和0.1至9 wt。氧化铈上掺杂的纳米比亚或塔塔拉的百分比。尽管常规的SCR催化剂可以在更高的温度下失活,但是掺杂的二氧化铈,特别是具有低至1或2重量%的二氧化铈。 Nb 2 O 5或Ta 2 O 5的%通过煅烧被活化为NO x转化。掺杂的二氧化铈对于SCRF®催化过滤器的应用也很有价值,包括后处理系统,该系统包括具有入口和出口的柴油机颗粒过滤器,以及涂覆在入口,出口或两者上的双功能催化剂。与传统的SCR催化剂相比,纳米比亚或钽掺杂的二氧化铈使NO2含量更高。
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