Comparative study on the synthesis and photocatalytic performance of Bi2WO6 nanosheets prepared via molten salt and hydrothermal method

Abstract

In this study, Bi2WO6 nanosheets were synthesized via molten salt (M-Bi2WO6) and hydrothermal method (H-Bi2WO6), respectively. Powder X-ray diffraction and scanning electron microscopy measurements demonstrated that the as-prepared Bi2WO6 samples preferred orientated alone {001} plane in both hydrothermal and molten salt system, enabling the formation of Bi2WO6 nanosheets. The results of UV–vis diffuse reflection spectrum showed that the M-Bi2WO6 nanosheets exhibited an obvious red shift in visible light absorption band in comparison with H-Bi2WO6 nanosheets, and the band gap of M-Bi2WO6 and H-Bi2WO6 nanosheets was 2.49 and 2.62 eV, respectively. As a result, the M-Bi2WO6 nanosheets reached as high as 97.13% of photodegradation efficiency of Rhodamine B under 180 min of sunlight irradiation, which was two times higher than that of the H-Bi2WO6 nanosheets (86.88%). Meanwhile, the photodegradation rate over M-Bi2WO6 (97.30%) for TC degradation was about two times higher than that of H-Bi2WO6 (78.58%). The much-enhanced photocatalytic performance of M-Bi2WO6 nanosheets was attributed to the better crystallinity, higher light-harvesting capability and superior sorption capacity. Basing on the detailed experimental study and analysis, this work could be a practical guidance for the fabrication of Bi2WO6-based microstructures with enhanced photocatalytic efficiency.