Insight into the H2S selective catalytic oxidation performance on well-mixed Ce-containing rare earth catalysts derived from MgAlCe layered double hydroxides
Insight into the H2S selective catalytic oxidation performance on well-mixed Ce-containing rare earth catalysts derived from MgAlCe layered double hydroxides
复制标题
深入研究源自 MgAlCe 层状双氢氧化物的混合良好的含 Ce 稀土催化剂的 H2S 选择性催化氧化性能
DOI：
10.1016/j.jhazmat.2017.09.014
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发表时间：
2018
影响因子：
13.6
通讯作者：
Siqiu Qu
中科院分区：
文献类型：
--
作者：
Fenglian Zhang;Xin Zhang;Zhengping Hao;Guoxia Jiang;Hongling Yang;Siqiu Qu
以层状双氢氧化物为原料，制备了一系列混合均匀的含铈MgAlCe稀土催化剂，并对H2S选择性催化氧化反应进行了研究。特别是，没有化学吸附O-空位，但本征缺陷位存在于催化剂表面上。值得注意的是，催化剂表现出优异的催化活性，合理的耐久性，和突出的硫选择性（100%）在相对较低的温度。催化剂的失活主要是由于Ce 3+被O2氧化为Ce 4+的速率低于Ce 4+被H2S还原为Ce 3+的速率。特别是，添加的水（一种刘易斯碱）可以与低效的S8催化剂竞争对刘易斯酸位点和活性位点的占据。同时，它还能改变催化剂表面的性质，使硫的存在形式由低效的S8催化剂转变为失活的S3。从而降低了沉积的低效S8催化剂含量。从而降低催化活性。
A series of well-mixed Ce-containing MgAlCe rare earth catalysts derived from layered double hydroxides were synthesized and tested for H2S selective catalytic oxidation. Particularly, no chemisorption O-vacancies but intrinsic defect sites were present on catalyst surface. Significantly, the catalysts exhibited excellent catalytic activity, reasonable durability, and outstanding sulfur selectivity (100%) at relatively low temperatures. Furthermore, the catalyst followed a step-wise mechanism, and the catalyst deactivation was due mainly to the slower oxidation rate of Ce3+to Ce4+by O2as compared to the reduction rate of Ce4+to Ce3+by H2S. Particularly, the added water, a Lewis base, can compete with inefficient S8catalyst for the occupation of Lewis acid sites and active sites. Meanwhile, it can change the characteristics of catalyst surface, resulting in sulfur existing form transforming from inefficient S8catalyst to inactive S3. Thus, lead to a decrease of deposited inefficient S8catalyst content. Consequently, decrease the catalytic activity.