Green and Efficient Liquid-Phase Exfoliation of BiI3 Nanosheets for Catalytic Carbon–Carbon Cross-Coupling Reactions

Bismuth iodide (BiI3) is one of the most excellent nontoxic two-dimensional (2D) layered materials and has attracted increasing attention due to its unique electronic structure and properties. However, the lack of highly effective exfoliation methods for mass production of 2D BiI3 nanosheets hampers their industrial applications. Herein, a facile liquid-phase exfoliation strategy is proposed for the first time to exfoliate the bulk BiI3 powder into few-layer BiI3 nanosheets in high yields and high dispersion contents in green solvents and their mixtures. It is found that the yield of BiI3 nanosheets is as high as about 30% and the dispersion content is up to 1.56 mg/mL. The thickness of nanosheets is 5–10 nm and the lateral dimension is around 1 μm, which is by far the thinnest nanosheet. The solvent–cosolvent interactions in mixed solvents are a critical factor in the liquid-phase exfoliation. In addition, the BiI3 nanosheets have been used as catalysts to improve the C–C cross-coupling reaction between phenyl boronic acid and aryl iodides, and the yield of biphenyl is 91%, which is higher than the highest value (80%) reported in the literature. Thus, the liquid exfoliation strategy reported here has great potential in large-scale and green production of BiI3 nanosheets for high activity catalysis.