Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, 8000, Aarhus, Denmark.
Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, 8000, Aarhus, Denmark.
Nat Commun. 2018 Jun 7;9(1):2211. doi: 10.1038/s41467-018-04615-9.
Hydrodesulfurization catalysis ensures upgrading and purification of fossil fuels to comply with increasingly strict regulations on S emissions. The future shift toward more diverse and lower-quality crude oil supplies, high in S content, requires attention to improvements of the complex sulfided CoMo catalyst based on a fundamental understanding of its working principles. In this study, we use scanning tunneling microscopy to directly visualize and quantify how reducing conditions transforms both cluster shapes and edge terminations in MoS and promoted CoMoS-type hydrodesulfurization catalysts. The reduced catalyst clusters are shown to be terminated with a fractional coverage of sulfur, representative of the catalyst in its active state. By adsorption of a proton-accepting molecular marker, we can furthermore directly evidence the presence of catalytically relevant S-H groups on the Co-promoted edge. The experimentally observed cluster structure is predicted by theory to be identical to the structure present under catalytic working conditions.
加氢脱硫催化作用可确保对化石燃料进行升级和净化，以符合对 S 排放越来越严格的法规。未来，随着更多种类和低质量的高含硫原油供应的增加，需要关注复杂的硫化 CoMo 催化剂的改进，这需要基于对其工作原理的基本理解。在这项研究中，我们使用扫描隧道显微镜直接观察和量化还原条件如何改变 MoS 和促进的 CoMoS 型加氢脱硫催化剂中簇形状和边缘端基的变化。还原后的催化剂簇被证明是以硫的部分覆盖来终止的，这代表了催化剂的活性状态。通过吸附质子接受分子标记物，我们可以进一步直接证明在 Co 促进的边缘上存在与催化相关的 S-H 基团。实验观察到的簇结构通过理论预测与催化工作条件下存在的结构相同。
