Catalytic open metal sites in Ti-MOFs obtained through plasma treatment for oxidative desulfurization

Abstract

Titanium-based metal–organic frameworks (Ti-MOFs) are known for their redox catalytic potential, inherently limited by coordination saturation. Defect engineering introduces the unsaturated metal sites, but introducing defects for improved performance is challenging due to titanium's hydrolysis tendency and the absence of stable Ti-clusters. This study employs an Ar plasma post-synthesis treatment, adjusting defect quantities by varying duration and intensity. The resulting plasma-induced defective MUV-10, with nearly 50 % missing linkers per cluster, displays heightened catalytic activity in oxidative desulfurization. This activity directly correlates with missing linker numbers, emphasizing the superior activity of defective open sites. Defect formation enhances intrinsic activity around unsaturated metal catalytic sites, rather than increasing active site density. This defect-generation method is adaptable to other Ti-MOFs and potentially to diverse MOFs.