Effects of Titania Coatings on Hydrodesulfurization Catalysts: Insights from First-principles Calculations

To establish guidelines for the development of high activity hydrodesulfurization catalysts, first-principles calculations were carried out with Al2O3 as the catalyst support and MoS2 as the supported metal species, focusing on the TiO2 coating and support-metal interaction. MoS2 clusters were modeled on the surfaces of Al2O3 and TiO2 and the adsorption energy was calculated. TiO2 showed stronger interaction with MoS2 than Al2O3. MoS2 clusters were also modeled on Al2O3 supports coated with thin films of TiO2, and the adsorption energy was calculated. Adsorption energy depended on the number of stacked film layers, suggesting that thin film thickness can be optimized. An amorphous Al2O3 support model was created to approach the real surface state and adsorption calculations were performed. Adsorption energy was higher than with a crystalline support, and the presence of sites where more stable adsorption would occur was confirmed.