Co-promoted MoS2 for hydrodesulfurization: New preparation method of MoS2 at room temperature and observation of massive differences of the selectivity depending on the activation atmosphere
Co-promoted MoS2 for hydrodesulfurization: New preparation method of MoS2 at room temperature and observation of massive differences of the selectivity depending on the activation atmosphere
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DOI：
10.1016/j.apcata.2015.03.003
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发表时间：
2015-05
影响因子：
5.5
通讯作者：
F. Niefind;W. Bensch;M. Deng;L. Kienle;J. Cruz-Reyes;José Mario Del Valle Granados
中科院分区：
文献类型：
--
作者：
F. Niefind;W. Bensch;M. Deng;L. Kienle;J. Cruz-Reyes;José Mario Del Valle Granados
以三-（N，N-二甲基二硫代氨基甲酸）-钴（III）为助剂源，以一种新的非晶态MoS 2为前驱体，制备了Co-MoS 2加氢脱硫催化剂。通过在三种不同温度（350、380和410 °C）下在合成气体气氛（H2/N2）或氮气气氛中热分解来获得样品。HDS反应的催化活性和选择性表现出令人惊讶的结果。在合成气中活化的一组催化剂显示出对直接脱硫（DDS）路径的明显偏好，而在氮气中活化的样品对DDS途径的活性较低。该结果表明在H2/N2中合成的催化剂中在MoS 2纳米晶的边缘上有更好的Co分散。活化温度是影响催化剂活性的重要因素。在H2/N2和N2中制备的活性最高的催化剂分别在380和410 °C下处理。在加氢脱硫前，所有催化剂上都能观察到硫化钴物种的相分离，而在加氢脱硫后，大部分硫化钴物种消失。活性最高的催化剂具有最低的MoS 2层堆积和最短的板长。通过化学分析、X射线衍射（XRD）和高分辨透射电子显微镜（HRTEM）等手段对催化剂进行了表征，揭示并讨论了HDS反应中选择性和活性差异的原因。
Co-promoted MoS2catalysts for hydrodesulfurization (HDS) were prepared from a new amorphous MoS2precursor and tris-(N,N-dimethyldithiocarbamato)-cobalt(III) as promoter source. The samples were obtained by thermal decomposition in either forming gas atmosphere (H2/N2) or nitrogen atmosphere at three different temperatures (350, 380 and 410 °C). The catalytic activities and selectivity for the HDS reaction exhibit surprising results. The set of catalysts activated in forming gas show a clear preference for the direct desulfurization (DDS) path, while samples activated in nitrogen are less active for the DDS route. This result indicates a better Co dispersion over the edges of MoS2nanocrystallites in the catalysts synthesized in H2/N2. The activation temperature is shown to be an important factor for the catalytic activity. The most active catalysts prepared in H2/N2and N2were treated at 380 and 410 °C, respectively. Phase segregation of Co sulfide species could be observed for all catalysts before the HDS, while after the catalytic tests most of the Co species vanished. The most active catalysts exhibit the lowest stacking of MoS2layers and the shortest slab lengths. The catalysts are intensively characterized by means of chemical analyses, X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM) and the reasons for the differences in selectivity and activity during the HDS reaction are revealed and discussed.