Formation of active species for propane dehydrogenation with hydrogen sulfide co-feeding over transition metal catalyst
Formation of active species for propane dehydrogenation with hydrogen sulfide co-feeding over transition metal catalyst
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DOI：
10.1016/j.apcata.2019.117238
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发表时间：
2019-10-25
影响因子：
5.5
通讯作者：
Fukuhara, Choji
中科院分区：
文献类型：
--
作者：
Watanabe, Ryo;Hirata, Nozomu;Fukuhara, Choji
本论文研究了以过渡金属（Fe，Co，Ni，Mn，Cu）为催化剂，硫化氢（H2S）为原料，丙烷脱氢（PDH）制丙烯的新工艺。SiO2负载的Fe（Fe/SiO2）催化剂被认为是高活性和选择性的PDH与共同进料H2S。Fe/SiO_2催化剂的稳定性高于CrOx/γ-Al_2O_3催化剂。Fe/SiO2催化剂的耐久性通过改变H2S与丙烷的比率（H2S/C3-）从0.2到2.6来调整：在H2S/C3-比率低于0.4的Fe/SiO2催化剂上获得最稳定的性能50 h。采用XRD、XPS和XAFS等分析手段研究了Fe/SiO2催化剂上活性中心的结构。H2S的共同供应促进了反应过程中硫化铁物种的形成，这是PDH的活性位点。热力学计算表明，硫化铁活性相是非化学计量的，例如，Fe 1-xS。这种结构通过共供应H2S来维持。DFT计算的脱氢路径表明，PDH发生在一个硫化铁活性中心通过中间体的丙基与表面硫离子结合。
This study focuses on a novel route for propylene production using a transition metal (Fe, Co, Ni, Mn, Cu) catalyst via propane dehydrogenation (PDH) with co-feeding hydrogen sulfide (H2S). The SiO2-supported Fe (Fe/SiO2) catalyst was found to be highly active and selective for PDH with co-feeding H2S. The Fe/SiO2 catalyst displayed higher stability than the commercial CrOx/gamma-Al2O3 catalyst. The durability of the Fe/SiO2 catalyst was tuned by changing the ratio of H2S to propane (H2S/C-3) from 0.2 to 2.6: the most stable performance was obtained over the Fe/SiO2 catalyst with a H2S/C-3 ratio of below 0.4 for 50 h. The structure of the active site on the Fe/SiO2 catalyst was investigated using XRD, XPS, and XAFS analyses. The co-supplying of H2S promoted formation of an iron sulfide species during the reaction, which was the active site for PDH. The thermodynamic calculations indicate that the iron sulfide active phase was non-stoichiometric, e.g., Fe1-xS. This structure was maintained by co-supplying H2S. DFT calculations of the dehydrogenation path suggest that PDH occurs on an iron sulfide active site via an intermediate of the propyl group combining with the surface sulfide ion.