Bandgap tuning and photocatalytic activities of CuSe1–xSx nanoflakes

Hexagonal CuSe1−xSx nanoflakes with 200–600 nm edge in length and 15–20 nm thick have been successfully synthesized via a concentrated alkaline hydrothermal method from CuCl, Se and S powders. Experimental results indicate that the reaction conditions such as NaOH concentration, reaction temperature, surfactant category and Cu source greatly affect the morphology of as-synthesized CuSe1−xSx nanoflakes. Moreover, their bandgaps are tunable as a function of x (0.1–0.5), which can be easily realized by changing the ratio of Se/S in the starting mix. The photocatalytic degradation of organic methylene blue (MB) with CuSe1−xSx and H2O2 addition under visible light irradiation has also been studied. Degradation time for the MB aqueous solution (2×10−5 M) was about 15 min for CuSe1−xSx nanoflakes with different x values (0.1–0.5), indicating the excellent photocatalytic activities of the hexagonal CuSe1−xSx nanoflakes.