Facile synthesis of tube-shaped Mn-Ni-Ti solid solution and preferable Langmuir-Hinshelwood mechanism for selective catalytic reduction of NOx by NH3
Facile synthesis of tube-shaped Mn-Ni-Ti solid solution and preferable Langmuir-Hinshelwood mechanism for selective catalytic reduction of NOx by NH3
复制标题
管状Mn-Ni-Ti固溶体的简便合成和NH3选择性催化还原NOx的优选Langmuir-Hinshelwood机理
DOI：
10.1016/j.apcata.2017.10.010
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发表时间：
2018-01-05
影响因子：
5.5
通讯作者：
Wang, Shaobin
中科院分区：
文献类型：
--
作者：
Liu, Jie;Li, Xinyong;Wang, Shaobin
我们提出了一种用于NH3选择性催化还原NOx的管状Mn-Ni-Ti固溶体（NH3- scr），该固溶体通过简单的自模板脲均相沉淀法，导致MnOx和NiOx活性物质在TiO2晶格中精细分散。Mn/Ni/Ti比是影响Mn-Ni-Ti固体溶液结晶度的重要因素，Mn/Ni/Ti比为2/3/5 （Mn2-Ni3）的催化剂表现出明显的结构畸变。丰富的表面缺陷诱导更多的Mn4+物质生成，表面吸附氧和Lewis酸位点，加速NO分子的吸附和活化。适当的Mn/Ni比抑制了NH3与NO的竞争吸附，促进了Langmuir-Hinshelwood （L-H）机制形成N-2，这是一个比Eley-Rideal （E-R）机制更快速的途径。L-H机制的容易发生显著提高了催化剂的SCR性能。
We present a tube-shaped Mn-Ni-Ti solid solution for the selective catalytic reduction of NOx with NH3 (NH3-SCR) through a facile self-templated urea-homogeneous precipitation method, which leads to the fine dispersion of the MnOx and NiOx active species in the TiO2 lattice. The ratio of Mn/Ni/Ti is an important factor to affect the crystallinity of Mn-Ni-Ti solid sulotion, and the catalyst with a Mn/Ni/Ti ratio of 2/3/5 (Mn2-Ni3) exhibits the significant structure distortion. The abundant surface defects induce more generation of Mn4+ species, surface adsorbed oxygen and Lewis acid sites, and acclerate the adsorption and activation of NO molecules. The appropriate Mn/Ni ratio inhibits the competitive adsorption of NH3 with NO, and facilitates the Langmuir-Hinshelwood (L-H) mechanism to form N-2, which acts as a much more rapid pathway in comparison to the parallel one following Eley-Rideal (E-R) mechanism. The readily occurence of L-H mechanism significantly improves the SCR performance of catalyst.