Effect of sulfidation atmosphere on the performance of the CoMo/γ-Al2O3 catalysts in hydrodesulfurization of FCC gasoline

• The CoMo/γ-Al2O3 catalysts sulfided in H2S/N2 showed much high selectivity.
• Sulfidation of active components in H2S/N2 was more completed than that in H2S/H2.
• The catalytic performance was mainly determined by the first sulfidation atmosphere.
• The MoS2 morphology differences could better explain the HDS selectivity.
• Controlling the slab lengths of supported MoS2 could regulate its HDS selectivity.

The effect of sulfidation atmosphere (H2S/H2 and H2S/N2) on the morphology of (Co)MoS2 particles supported on γ-Al2O3 was studied and the prepared catalysts were evaluated in selective hydrodesulfurization (HDS) of FCC gasoline. It was found that the selectivity of the CoMo/γ-Al2O3 catalysts sulfided in H2S/N2 was 1.8 times as high as that sulfided in H2S/H2, and the catalytic performance was mainly determined by the first sulfidation atmosphere after the impregnation of Mo. The characterization by XRD, HRTEM, XPS, TPR and FT-IR showed that the more completed sulfidation of Mo oxides in H2S/N2 could effectively weaken the strong interaction between the γ-Al2O3 support and active components, thus inducing the decisive influence on the morphology of MoS2 particles. The MoS2 morphology differences could better explain the HDS selectivity. The CoMo/γ-Al2O3 catalyst sulfided in H2S/N2 showed significantly longer slab lengths of supported MoS2 slabs, which effectively decreased the number of active adsorption sites for olefins and thus suppressed the hydrogenation activity of olefins, leading to a desirable higher HDS selectivity. Therefore, a tailor-made catalyst with high HDS selectivity could be developed by optimally controlling the slab lengths of supported MoS2 slabs.

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