Stable and improved visible-light photocatalytic hydrogen evolution using copper(II)-organic frameworks: engineering the crystal structures

Relatively high photocatalytic H-2 production activities can be exhibited by metal-organic framework (MOF) materials using a compulsory cocatalyst or photosensitizer. However, no study has focused on the effect of the crystal structures of MOF materials on the photocatalytic H-2 evolution activity when using the same organic ligand and metal ion. Therefore, by connecting the 4'-(2,4-disulfophenyl)-3,2': 6',3''-terpyridine ( H2DSPTP) organic ligand with CuSO(4)5H(2)O, different MOF photocatalyst crystalline structures, (1) and (2), were obtained. These products were then respectively characterized and employed for photocatalytic H-2 evolution. In the absence of any photosensitizer and cocatalyst, compounds 1 and 2 exhibited efficient visible-lightdriven photocatalytic H-2 production at maximum rates of 5.77 mmol h(-1) and 6.99 mu mol h(-1). Interestingly, compounds 1 and 2 also exhibited photocatalytic H-2 generation when irradiated with near-infrared light. Compound 2 showed outstanding long-termstability, as evidenced by eight-cycle tests over 24 h. The charge separation and transfer process of the compounds were verified using PL, time-resolved PL spectroscopy, and photocurrent measurements.