Preparation and catalysis of defected PVMo4W7@rht-MOF-1 for oxidation desulfurization under air

Abstract

Aerobic oxidative desulfurization (AODS) is a promising deep desulfurization technique that can efficiently remove organosulfur compounds under mild conditions. In this study, a one-pot hydrothermal method was designed to encapsulate a quaternary heteropolyacid H4PVMo4W7O40 (PVMo4W7) into rht-MOF-1 {rht-MOF-1 = [Cu6O(TZI)3(H2O)6]4⋅nH2O}, and the single crystal structure of H4PVMo4W7O40@rht-MOF-1 (1) indicated that PVMo4W7 was effectively encapsulated within cage C of rht-MOF-1. Further, a similar one-pot hydrothermal reaction was employed to introduce acetic acid, resulting in the synthesis of defective H4PVMo4W7O40@rht-MOF-1-De (1-De). 1-De was characterized using various techniques such as FT-IR, XRD, TGA, XPS, and EPR. In comparison with 1, 1-De exhibited numerous defect sites, high porosity, high surface area, high Mo5+ ion content, well-dispersed PVMo4W7, and abundant oxygen vacancies, leading to efficient AODS capability. When applied as catalyst, 1-De demonstrated high catalytic activity and good recyclability for the oxidation of dibenzothiophene (DBT) and 4,6-dimethyl dibenzothiophene (4,6-DMDBT) under air atmosphere. Strikingly, the removal rates of DBT and 4,6-DMDBT reached 99 % and 96 %, respectively under optimized conditions.