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

• The controllable synthesis of Bi 2 O 3 -MoO 3 binary metal composite oxides. • The γ-Bi 2 MoO 6 catalyst exhibited the outstanding deep catalytic oxidation ability. • The Structure-activity relationship of catalyst on ODS was discussed. • The mechanisms of ODS were explored. The deep removal of sulfide from fuel oil is the key to the production of clean energy using Bi 2 O 3 -MoO 3 binary semiconductor materials that effectively improve the activity of the catalytic reaction. In this study, the controllable synthesis of Bi 2 O 3 -MoO 3 binary metal composite oxides with different crystalline phases (α, β, and γ) 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 γ-Bi 2 MoO 6 catalyst had higher catalytic activity than α-Bi 2 Mo 3 O 12 and β-Bi 2 Mo 2 O 9. At 65℃, γ-Bi 2 MoO 6 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 γ-Bi 2 MoO 6 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. [ABSTRACT FROM AUTHOR]