Cobalt promoted molybdenum carbide supported on γ-alumina as an efficient catalyst for hydrodesulfurization of dibenzothiophene

The development of new hydrodesulfurization (HDS) catalysts with suitable electronic structure and metal-support interaction are critical for the efficient removal of sulfur from oil. In this work, cobalt-promoted molybdenum carbide supported on mesoporous alumina (CoxMo2C/MA) catalysts were prepared by a simple one-step hydrolysis method combined with a temperature programmed carbonization process, and the effects of Co on the physicochemical properties and HDS performance of the catalysts were systematically investigated. The results show that the appropriate Co addition can reduce the interaction between Mo species and alumina support, which is beneficial for the carbonization of Mo. Besides, the introduction of Co makes Mo species electron-rich, causing the C-S bond is vulnerable to attack. Taking dibenzothiophene (DBT) as a probe, Co0.3Mo2C/MA shows significant high sulfur removal efficiency (about 100%) and effective direct desulfurization selectivity. Furthermore, the density functional theory calculations further prove that the activation energy barrier of DBT HDS at the Co-Mo2C site is lower than that of Mo2C, confirming its reaction is easier to proceed. This work may provide a strategy for accessing new efficient modified molybdenum carbide catalysts for the HDS field.

Automated summary

This study prepared cobalt-promoted molybdenum carbide supported on mesoporous alumina catalysts and systematically investigated the effects of cobalt on the physicochemical properties and hydrodesulfurization (HDS) performance of the catalysts. The results showed that suitable cobalt addition reduced the interaction between molybdenum species and alumina support, allowing for better carbonization of molybdenum. The introduction of cobalt made the molybdenum species electron-rich, resulting in easier attack on the C-S bond. The Co0.3Mo2C/MA catalyst exhibited significant sulfur removal efficiency and effective direct desulfurization selectivity.