Facile fabrication of porous ZnO by thermal treatment of zeolitic imidazolate framework-8 and its photocatalytic activity

In this work, porous ZnO photocatalysts were attempted to be prepared by a facile method, i.e. the thermal treatment of zeolitic imidazolate framework-8, and then characterized using X-ray diffraction (XRD), field-emission scanning electron microscopy (FESEM), Fourier transform infrared (FTIR) spectroscopy and nitrogen adsorption-desorption. It was found that the calcination temperature and time significantly influenced the morphology, composition and pore structure of ZnO. The photocatalytic activities of as-prepared ZnO powders were evaluated in the degradation of methylene blue (MB) under UV light in comparison with commercial anatase TiO₂ and Degussa P25 TiO₂. The surface area and crystallinity of porous ZnO obviously affected the photocatalytic activity of ZnO. The ZnO prepared at 500 °C for 5 h (ZnO-500-5) showed the highest photocatalytic activity, which was higher than that of the commercial anatase TiO₂ and lower than that of Degussa P25 TiO₂.