Solvent and temperature-mediated nanoarchitectonics of hierarchical Bi2MoO6 for efficient antibiotic degradation

Abstract

Bismuth molybdate (Bi2MoO6) is typically synthesized via the solvothermal method. Elucidating the governing effects of solvent type and reaction temperature on its phase, morphology, and properties is essential for the rational design of tailored materials. In this study, Bi2MoO6 was prepared through a solvothermal approach employing four distinct solvents: water, ethanol, N,N-dimethylformamide (DMF), and ethylene glycol. The influence of reaction temperature on the material's structure evolution was also systematically investigated. The microstructure of Bi2MoO6 was found to be strongly dependent on the boiling point of the solvent employed. In particular, solvents with higher boiling points led to an increased concentration of oxygen vacancies within the Bi2MoO6 structure. When low-boiling-point solvents were used, a phase transition occurred, yielding bismuth oxide as a by-product. Furthermore, the effect of solvothermal temperature on the structural characteristics of Bi2MoO6 was examined. At lower reaction temperatures, the product exhibited an amorphous nature. With increasing temperature, the crystallite size of Bi2MoO6 grew progressively until metallic bismuth emerged. Notably, Bi2MoO6 synthesized at 140 °C demonstrated optimal degradation efficiency toward ciprofloxacin, which can be attributed to its relatively small crystallite size and a suitable concentration of oxygen vacancies. This study offers valuable guidance for the rational regulation of solvent-mediated catalytic materials.