Construction of CuO-modified zeolitic imidazolate framework-9 for photocatalytic hydrogen evolution

An efficient CuO-modified zeolitic imidazolate framework-9 (ZIF-9) photocatalyst is successfully prepared at room temperature under mild conditions. It is observed that the ZIF-9/CuO photocatalyst is effective for H 2 generation under visible light with sacrificial agent conditions. When the CuO is introduced, the photocatalytic properties of ZIF-9 are greatly improved and when the content of CuO is 40%, the photocatalytic activity reaches a maximum of 78.74 μmol after 5 h. This results from the 200–300 nm cube structure of ZIF-9 being able to adsorb more dye molecules and the CuO, which connects with ZIF-9, greatly improving the electronic transmission efficiency. Moreover, the interaction between the dye molecule Eosin Y (EY) and the catalyst is also studied by transient fluorescence spectroscopy. A series of characterizations, such as SEM, TEM, XPS, XRD, UV-vis, FTIR, transient fluorescence and photocurrent, are conducted, and the results are in good agreement with the experimental result. In addition, the possible reaction mechanism over EY-sensitized ZIF-9/CuO under visible light irradiation is proposed. A photocatalyst containing cube ZIF-9 and CuO is synthesized and shows a high photocatalytic activity that is 19.4 times that of g-C 3 N 4 /CuO. The large specific surface area of ZIF-9 plays an important role.