Two stable 3D polyoxometalate-based metal-organic frameworks (PMOFs), [Cu(trz)(HO)][α-SiWO]·2HO (1) and [Cu(trz)Cl][α-PWO] (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(trz)], but polyoxoanion (POA) template effect leads to different structures and properties: 1 represents an interesting example that [α-SiWO] locate in the nine-membered Cu-trz rings through Cu···O weak interactions to form a 3D framework, whereas 2 shows a 3D structure constructed from 2D bilayer cationic network [Cu(trz)Cl] and [α-PWO] lying in the adjacent layers via Cu···O weak interactions. PMOF 1 as unusual visible-light photocatalyst exhibit significantly enhanced photocatalytic activity under visible-light and excellent stability during the photocatalysis process for recovering and recycling, as well as photocatalytic hydrogen evolution activity.
