Assembly of three stable POM-based pillar-layer CuI coordination polymers with visible light driven photocatalytic properties

Abstract

Three new POM-based pillar-layer Cu^I coordination polymers (CPs), Cu^I₁₂Cl(trz)₈[PW₁₂O₄₀] (1), Cu^I₁₂Cl(trz)₈[PMo₁₂O₄₀] (2) and Cu^I₁₂Cl(trz)₈[HSiW₁₂O₄₀] (3) (trz = 1,2,4-triazole), have been hydrothermally synthesized. Characterized by single-crystal X-ray diffraction analyses, compounds 1–3 are isostructural, and copper ions coordinate with trz to form double layers with the help of Cl ions, which are supported by POMs to a 3D framework with continuous channels. The same two frameworks interwine to form a 3D two-fold interpenetrating network. The compounds display high heat stability and excellent acid and alkali resistance. Ultraviolet-vis diffuse-reflectance spectra suggest that compounds 1–3 exhibit their nature of semi-conductivity. Thus, reactions of photocatalytic degradation of organic dye were performed, and its relevant photocatalytic mechanism was also finely investigated. All the title compounds show efficient visible-light-driven photocatalytic activities in the degradation of organic dyes. Moreover, hydroxyl radicals (˙OH) are proved to play a crucial role in visible photocatalytic degradation reaction.