Low-temperature hydrothermal synthesis of BiFeO3 microcrystals and their visible-light photocatalytic activity

Highlights: ► Urea-assisted hydrothermal synthesis of pure BiFeO3 at 120 °C was reported. ► Possible formation mechanism of pure phase BiFeO3 at low temperature was illuminated. ► BiFeO3 microcrystals exhibited efficient visible-light photocatalytic activity. -- Abstract: Pure BiFeO3 (BFO) microcrystals were synthesized at the temperature as low as 120 °C via a urea-assisted hydrothermal process. The crystal structure, morphology and photocatalytic property of BFO microcrystals were investigated. The analysis reveals that the hydrolysis of urea in the hydrothermal process plays a key role in the synthesis of pure phase BFO microcrystals. FE-SEM and TEM results show that these BFO microcrystals present a nearly spherical microstructure, and specially exhibit superstructures consisting of large amounts of small particles with the size of 100–150 nm by further observation. Moreover, these BFO microcrystals exhibit efficient photocatalytic activity under visible-light irradiation, suggesting their promising applications as photocatalysts and related fields.