Weise, C F, Falsig, H, Moses, P G, Helveg, S, Brorson, M & Hansen, L P 2021, ' Single-atom Pt promotion of industrial Co-Mo-S catalysts for ultra-deep hydrodesulfurization ', Journal of Catalysis, vol. 403, pp. 74-86 . https://doi.org/10.1016/j.jcat.2021.03.008
We introduce a tertiary transition metal sulfide nanostructure, Pt-Co-Mo-S, for catalytic hydrodesulfurization (HDS) of sulfur-containing molecules in crude oil distillates with the aim to produce ultra-low sulfur transport fuels. The addition of ppm-levels of Pt to a standard industrial Co-Mo-S catalyst boosts the HDS activity by up to 46%. The promotional effect is examined by combining atomic-resolution Scanning Transmission Electron Microscopy (STEM), Energy Dispersive X-ray Spectroscopy (EDX), X-ray Absorption Near Edge Spectroscopy (XANES) and Density Functional Theory (DFT). It is shown that the Pt-Co-Mo-S catalyst contains predominantly single-layer MoS2 nanocrystals with Co atoms fully covering the S-edge terminations and Pt atoms uniquely attached to corner and edge sites in a platinum(IV) sulfide-like structural motif. Platinum is suggested to reduce the sulfur binding energy and increase the abundance of coordinately undersaturated sites (CUS) and not necessarily changing the reactivity towards 4,6-DMDBT molecules, although more elaborate studies are needed to address this in detail.