Novel shielding and synergy effects of Mn-Ce oxides confined in mesoporous zeolite for low temperature selective catalytic reduction of NOx with enhanced SO2/H2O tolerance
Novel shielding and synergy effects of Mn-Ce oxides confined in mesoporous zeolite for low temperature selective catalytic reduction of NOx with enhanced SO2/H2O tolerance
复制标题
Mn-Ce氧化物限制在介孔沸石中的新型屏蔽和协同效应，用于低温选择性催化还原NOx，并增强SO2/H2O耐受性
DOI：
10.1016/j.jhazmat.2020.122592
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发表时间：
2020
影响因子：
13.6
通讯作者：
Peng Honggen
中科院分区：
文献类型：
--
作者：
Yan Ran;Lin Sixue;Li Yonglong;Liu Wenming;Mi Yangyang;Tang Changjin;Wang Liang;Wu Peng;Peng Honggen
氮氧化物（NOx）是来自化石燃料燃烧的空气污染物的主要来源。Mn-Ce基催化剂虽然具有上级低温活性，但由于其在低温下具有较强的吸水性和硫酸盐物种形成倾向，其抗水和抗SO2能力不如其它金属氧化物催化剂。本文采用限制策略设计合成了一种新型Mn-Ce基催化剂，用于NH3选择性催化还原NOx。以介孔分子筛（ZSM-5）为壳层，Mn-Ce氧化物为活性核（MnCeOx@Z5），采用简单的一锅法组装了限制型MnCeOx催化剂。由于沸石壳的屏蔽效应以及氧化铝-二氧化硅沸石壳的酸性与混合氧化物核的氧化还原性质之间的协同作用，与负载在ZSM-5上的MnCeOx（MnCeOx/Z5）及其前体（MnCeOx@Al-SiO2）相比，新型MnCeOx@Z5催化剂显示出增强的抗水和抗SO2性能。显然，沸石鞘阻碍硫酸盐物种的形成，这一现象进一步研究了原位漫反射红外傅里叶变换光谱（原位DRIFTS）。本文提出的新型屏蔽和酸-氧化还原协同效应/策略可应用于设计其他高性能的脱硝催化剂，用于空气污染控制。
Nitrogen oxides (NOx) are a primary source of air pollutants from combustion of fossil fuels. Though Mn-Ce based catalysts exhibit superior low temperature activities, their water and SO2tolerance is inferior to other metal oxide catalysts, due to their strong water adsorption and sulfate species formation tendency at low reaction temperatures. Herein, a confinement strategy was adopted to design and synthesize a novel Mn-Ce based catalyst for selective catalytic reduction of NOxwith NH3. The confined MnCeOxcatalyst was assembled with a simple one pot method, using a mesoporous zeolite (ZSM-5) as the shell and Mn-Ce oxides as the active core (MnCeOx@Z5). Owing to the zeolite shell’s shielding effect and the synergy between the alumina-silica zeolite shell’s acidic properties and the mixed oxide cores’ redox properties, the novel MnCeOx@Z5 catalyst displayed enhanced water and SO2resistance as compared to the MnCeOxsupported on ZSM-5 (MnCeOx/Z5) and its precursor (MnCeOx@Al-SiO2). Evidently, the zeolite sheath hinders sulfate species formation, and this phenomenon was further investigated byin situdiffuse reflectance infrared Fourier transform spectroscopy (In situDRIFTS). The novel shielding and acid-redox synergy effect/strategy adopted in this work can be applied to design other high performance deNOxcatalysts for air pollution control.