Two Coordination Polymers Synthesized from Various N-Donor Clusters Spaced by Terephthalic Acid for Efficient Photocatalytic Degradation of Ibuprofen in Water under Solar and Artificial Irradiation

Abstract

Two coordination polymers CP1 {[Zn(II)(BIPY)(Pht)]n} and CP2 {[Zn(HYD)(Pht)]n} (BIPY = 4,4′-bipyridine, Pht = terephthalic acid, and HYD = 8-hydroxyquinoline) have been successfully synthesized by a hydrothermal process using zinc aqueous solution. The so-prepared compounds were characterized by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, UV–visible spectroscopy, thermogravimetric analysis (TGA), and cyclic voltammetry. XRD pointed to a crystalline phase for CP1, while CP2 required recrystallization, FTIR spectroscopy established the presence of characteristic bands for all the ligands, and TGA showed thermal stability up to 100 °C. The electrochemical study showed a good charge transfer between the ligands and Zn metal for both materials. The UV–vis spectra displayed a strong absorption band spreading over a wide wavelength range, encompassing UV and visible light, with a band gap of 2.69 eV for CP1 and 2.56 eV for CP2, both of which are smaller than that of ZnO. This provides an advantageous alternative to using ZnO. The 5 × 10–5 mol L–1 ibuprofen decomposition kinetics under solar and UV light were studied under different irradiation conditions. Good photocatalytic properties were observed due to their high surface area.