Polyoxometalate-Based Metal-Organic Frameworks as Visible-Light-Induced Photocatalysts

Two stable 3Dpolyoxometalate-based metal-organic frameworks (PMOFs), [Cu-12(I)(trz)(8)(H2O)(2)] [alpha-SiW12O40]center dot 2H(2)O (1) and [Cu-12(I)(trz)(8)Cl] [alpha-PW12O40] (2) (Htrz = 1-H-1,2,4-triazole) based on Keggin-type POMs were successfully obtained and fully characterized. The basic building units of the two PMOFs are [Cu-12(I)(trz)(8)], but polyoxoanion (POA) template effect leads to different structures and properties: 1 represents an interesting example that [alpha-SiW12O40](4-) locate in the nine-membered Cu-trz rings through Cu center dot center dot center dot O weak interactions to form a 3D framework, whereas 2 shows a 3D structure constructed from 2D bilayer cationic network [Cu-12(I)(trz)(8)Cl](3+) and [alpha-PW12O40](3-) lying in the adjacent layers via Cu center dot center dot center dot O weak interactions. PMOF 1 as unusual visible-light photocatalyst exhibit significantly enhanced photocatalytic activity under visible-light and excellent stability during the photocatalysis recycling, as well as photocatalytic hydrogen evolution activity.