From morphology control to photocatalytic activity: Magnetized water for the innovative and green synthesis of 2D layered BiOI and its application in the photodegradation of organic dyes using central composite design (CCD)

This study explores the innovative use of ordinary water as an eco-friendly solvent magnetized by a solvent magnetizing apparatus (SMA), which is referred to as magnetized water. This magnetized water is then used as a solvent to synthesize bismuth oxyiodide (BiOI) photocatalysts. Moreover, the morphologies and photocatalytic activity of the synthesized BiOI are investigated and compared with structures obtained using ordinary water. Techniques such as XRD, FESEM, BET, UV–Vis spectroscopy, PL, photocurrent response, DRS, and EIS were used to understand the characteristics and properties of the photoactive nanostructures. By optimizing the exposure time of the magnetic field applied to the water, the morphology of BiOI structures was effectively controlled, resulting in the formation of three-dimensional flower-like nanostructures from two-dimensional nanosheets. The photocatalytic performance of BiOI was evaluated under visible light irradiation, demonstrating enhanced performance with approximately 95 % degradation for Rhodamine B (RhB) by Bi−15 and Congo Red (CR) by Bi-1 pass photocatalysts in almost 45 min. Statistical analysis using Design Expert software highlighted the significant effect of pH, irradiation time, and photocatalyst dosage on the degradation. Kinetic studies followed first-order kinetics according to the pseudo-first-order model for both RhB and CR degradation. Finally, the stability of the photocatalysts was investigated, and no significant decrease in the performance of photocatalysts was observed after five cycles. Additionally, using magnetized water can lower synthesis costs by enhancing reaction efficiency and reducing the need for expensive chemicals and energy.