Yurtsever, Husnu ArdaCetin, Ali Emrah2025-01-062025-01-0620210927-77571873-435910.1016/j.colsurfa.2021.1269802-s2.0-85107791117https://doi.org/10.1016/j.colsurfa.2021.126980https://hdl.handle.net/20.500.14669/2864The effects of crystallization time and amount of Zeolitic Imidazolate Framework-8 (ZIF-8) on the photocatalytic activity of ZIF-8 decorated copper (Cu) doped titania (TiO2) (ZIF-8/Cu-TiO2) powders were investigated in this study. The formation of nanocomposite structure of ZIF-8 crystals grown over the surface of core Cu-TiO2 particles containing heterojunction sites was observed at low ZIF-8 level. Powders containing ZIF-8 in the 5-46% range (weight basis) were synthesized and their activities in the photocatalytic degradation of an organic dye molecule were evaluated. X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (ATR-FTIR), thermal gravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and high resolution transmission electron microscopy (HR-TEM) analyses indicated that ZIF-8/Cu-TiO2 nanocomposite can be prepared at low levels of ZIF-8. HR-TEM images of 46% ZIF-8/Cu-TiO2 showed that Cu-TiO2 particles act as a core and ZIF-8 crystals grow over the surface of Cu-TiO2 particles during crystal growth and Cu-TiO2 particles were almost completely covered with ZIF-8 crystals. Photocatalytic activity increased with decreasing ZIF-8 level which was attributed to the formation of heterojunctions due to partial coverage of TiO2 surface. The 1st order reaction rate constant of ZIF-8/Cu-TiO2 nanocomposite containing 5% ZIF-8 was found to be 4 and 1.4 times that of bare ZIF-8 and CuTiO2, respectively. Partial coverage of TiO2 surface with ZIF-8 crystals lead to the formation of light exposed ZIF8/Cu-TiO2 heterojunction sites for the enhanced degradation of the dye molecule. The presence of ZIF-8 in the nanocomposite also increased the adsorption of the organic dye by the interaction with open Zn2+ metal sites of ZIF-8 on the nanocomposite surface. This study revealed that ZIF-8/Cu-TiO2 nanocomposites could be prepared at low ZIF-8 levels and short growth times with higher photocatalytic activities than their constituents and nanocomposites prepared at higher ZIF-8 levels and longer growth times.eninfo:eu-repo/semantics/closedAccessPhotocatalysisNanocompositeZIF-8TiO2HeterojunctionArticleQ1625WOS:000672810400001Q2