Selective solution-phase synthesis of BiOCl, BiVO4 and δ-Bi2O3 nanocrystals in the reaction system of BiCl3–NH4VO3–NaOH

In this study, we demonstrate a straightforward solution-phase method for the selective synthesis of BiOCl, BiVO4 and δ-Bi2O3 nanocrystals by simply manipulating the reaction temperature and the BiCl3-to-NaOH mole ratio in the reaction system of BiCl3–NH4VO3–NaOH. The experimental results revealed that BiOCl, as the sole product, was prepared when designating the reaction temperature ranging from room temperature to 100 °C, regardless of the BiCl3-to-NaOH mole ratio; on the other hand, BiOCl, BiVO4, and δ-Bi2O3 nanocrystals could be selectively prepared at 140–180 °C, depending on the BiCl3-to-NaOH mole ratio in solution. Significantly, we first report on fabricating δ-Bi2O3 sample, the high-temperature cubic phase commonly stabilized at 730–824 °C, at the low reaction temperature of 140–180 °C under solution-phase synthetic conditions. In addition, the δ-Bi2O3 sample exhibits strong emission at room temperature.