Controllable synthesis of Bi2O3-MoO3 binary system metal composite oxides and structure-activity relationships for aerobic oxidative desulfurization

The deep removal of sulfide from fuel oil is the key to the production of clean energy using Bi2O3-MoO3 binary semiconductor materials that effectively improve the activity of the catalytic reaction. In this study, the controllable synthesis of Bi2O3-MoO3 binary metal composite oxides with different crystalline phases (alpha, beta, and gamma) was realized via microwave hydrothermal method at the pH of 1 through the variation of the theoretical Bi/Mo molar ratio. The catalytic oxidative desulfurization (ODS) experiments revealed that gamma-Bi2MoO6 catalyst had higher catalytic activity than alpha-Bi2Mo3O12 and beta-Bi2Mo2O9. At 65celcius, gamma-Bi2MoO6 catalyst exhibited the outstanding deep catalytic oxidation ability for dibenzothiophene (DBT), benzo thiophene (BT), and 4,6-dimethyldibenzothiophene (4,6-DMDBT). After 7 times of recycling, the removal rate of DBT still reached 99.11%. According to the kinetic fitting data, the catalytic oxidative desulfurization of DBT in model oil by gamma-Bi2MoO6 conformed to the first-order kinetic equation with the reaction activation energy of 51.05 kJ/mol. Moreover, the possible mechanisms of ODS were explored. The ultrafast oxidation was concluded to be due to peroxo species produced through the action of composite metal oxides.

Automated summary

In this study, controllable synthesis of Bi2O3-MoO3 binary metal composite oxides with different crystalline phases (alpha, beta, and gamma) was achieved, where the gamma-Bi2MoO6 catalyst showed higher catalytic activity and deep oxidation ability for various sulfur compounds. It can be recycled multiple times and the oxidation process follows a first-order kinetic equation with a reaction activation energy of 51.05 kJ/mol.