Preparation of Porous Crystalline Zn(II)-tartrate Photocatalyst Ade H. Rafika1, Mohammad M. Khunur1, Rachmat T. Tjahjanto1, Yuniar P. Prananto1*
1Department of Chemistry, Faculty of Mathematics and Science, Brawijaya University, Malang, 65144, Indonesia
*Corresponding author: prananto[at]ub.ac.id
Abstract
Preparation of porous crystalline Zn(II)tartrate for heterogeneous photocatalyst is reported here. As a photocatalyst, crystal stability is one of many important factors. It is expected that more cycles of catalysis can be achieved if the crystallinity of the photocatalyst is stable. The Zn(II)tartrate was synthesized at room temperature using the top bench solution method with a ZnCl2 and KNa Tartrate molar ratio of 1 to 1 in an aqueous solution. The precipitated Zn(II)tartrate was then dried at various drying temperatures (80, 100, and 120 C) and drying times (1 and 2 hours). Solids obtained from each series were characterized by infrared spectroscopy, powder X ray diffraction, and diffuse reflectance spectroscopy (DRS). Infrared spectra of all sample series show characteristic functional groups of tartrates. X ray powder diffraction of the 1 hour treatment (100 and 120 C) and the 2 hours treatment (80, 100, and 120 C) show identical patterns of the anhydrous complex. Meanwhile, the 1 hour (80 C) treatment shows that the Zn(II)tartrate remains in the form of a hydrated complex, which is also evidenced by the broadband in the IR spectra. The 2 hours (100 C) treatment is suggested as the optimum treatment for the preparation of porous crystalline Zn(II)tartrate. The crystallinity of the obtained Zn(II)tartrate is around 74 up to 75% with 20 nm of average crystallite size. The DRS spectrum indicates that the Zn(II)tartrate prepared from the 2 hours (100 C) treatment has a high direct energy bandgap (5.54 eV) and absorbs UV light in the range of 200 up to 242 nm.
