A comparative study of the morphologies and photocatalytic performances of bis[5-(2-pyridyltetrazolato)]diaquazinc(II) framework synthesized by hydrothermal and microwave methods

The metal organic framework compound, bis[5-(2-pyridyltetrazolato)]diaquazinc(II) [(2-PTZ)2Zn(H2O)2], has been synthesized by the reaction of 2-cyanopyridine, Zn(NO3)2.4H2O and NaN3 via both microwave assisted and conventional hydrothermal processes. The product obtained by the microwave process shows needle-like morphology, while that obtained by the conventional process shows rhombohedral morphology. The MOFs are characterised by scanning electronic microscopy, BET surface area analysis, room temperature photoluminescence and UV–vis spectroscopy. IR spectroscopy and single-crystal X-ray crystallographic studies of the MOF obtained by the microwave process have also been carried out. The average crystallite sizes of the two products, as determined by powder X-ray diffraction are found to be 72 nm and 26 nm respectively. Band gaps of the MOFs calculated by using the Tauc plots are 2.8 and 3.1 eV respectively. Their photocatalytic behavior using methylene blue under UV-vis irradiation has been investigated.