Temperature-dependent synthesis of ZnO: effects on photoelectrochemical performance
摘要
Zinc oxide (ZnO) is a multifunctional material known for its unique physical and chemical properties, including a wide absorption range, high chemical stability, strong electrochemical binding coefficient, paramagnetic nature, and photostability. Among its key attributes, ZnO’s photocatalytic activity plays a crucial role in environmental remediation, enabling the decomposition of pollutants and the splitting of water into hydrogen and oxygen. In this study, undoped ZnO was synthesized thermally from zinc acetate dihydrate at temperatures ranging from 400 to 600 °C, without the use of dopants or templates, with the wurtzite phase confirmed by X-ray diffraction. Morphology and photocatalytic performance were strongly influenced by the synthesis temperature. Structural analysis revealed that single cylindrical particles (0.493–0.578 μm) were formed at 400–450 °C, which transitioned to agglomerates of cylinders (0.471 μm) at 500 °C, and smaller cylindrical agglomerates (0.295–0.343 μm) at higher temperatures. Characterization was carried out using scanning electron microscopy (SEM), X-ray energy dispersive spectroscopy (EDS), Fourier Transform Infrared Spectroscopy (FTIR), granulometry, Differential Scanning Calorimetry (DSC), and Thermogravimetric Analysis (TGA). ZnO thin films were fabricated by electrophoretic deposition on conductive glass at varying potentials (15–30 V) and electrolysis times (5–30 min). The ZnO synthesized at 500 °C yielded the most active and stable thin films, achieving a photocurrent density of 11.95 μA cm−2, photoelectrochemical efficiency of 2.65%, and photoconversion efficiency of 1.49%. These results highlight the importance of synthesis and deposition conditions in optimizing ZnO’s photocatalytic performance for environmental applications.
Graphical abstract