The preparation of Mo/γ-Al2O3 catalysts with controllable size and morphology via adjusting the metal-support interaction and their hydrodesulfurization performance

• We prepared MoS2/Al2O3 catalysts using Mo-based hybrid nanocrystals as the precursor.
• DTAB is a key factor affecting the nature of Mo-precursor and the morphology of MoS2.
• HDS activity is enhanced first and then dropped as increasing DTAB/Mo molar ratios.
• HDS of DBT proceeds predominantly through the DDS route.

In this work, a series of Mo/γ-Al2O3 catalysts have been prepared by using Mo species enwrapping with dodecyltrimethylammonium bromide (DTAB) as the novel precursors for the hydrodesulfurization (HDS) of dibenzothiophene (DBT). The objective of this work is to get a deep insight into the effect of the Mo precursors on the size and morphology of the active phases and HDS activity. DTAB as the organic additive for the preparation of Mo precursors can dominate the nature of precursor solution and adjust the metal-support interaction so as to control the dispersion and morphology of the active phases. It is clearly shown that the addition of DTAB can effectively decrease the strong interaction between the Mo species and γ-Al2O3 support and favor to tune the size and morphology of MoS2 nanoparticles. The optimum molar ratio of DTAB/Mo is 3/5 and the corresponding catalyst shows the highest sulfidation degree with the most suitable stacking layer numbers and the shortest length of MoS2 and thus exhibits the best HDS performance. Our work explores the important roles of organic additive to adjust the metal-support interaction and control the morphology of active phases and provides an effective precursor which can be used widely to prepare supported catalysts.

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