LAUSR

Construction of Z-scheme photocatalyst is considered to be a valid approach for using solar energy to produce hydrogen during water splitting. Herein, 2D/2D WO3/g-C3N4 heterojunction composite as photocatalyst was synthesized including exfoliation and heterojunction procedures with a simple, convenient and green method in the reverse microemulsion system via supercritical carbon dioxide (scCO2). Transmission electron microscopy, Atomic force microscopy, X-ray diffraction, Fourier transform infrared, Raman, N2 adsorption-desorption isotherms and X-ray photoelectron spectroscopy have been used to characterize their morphology, structure, chemical composition and surface chemical states of the as-prepared samples. The resultant W/CN-10.3 composite exhibited significant photocatalytic activities towards the hydrogen evolution during water splitting with the hydrogen evolution rate of 688.51 μmol g-1 h-1, which was more than 16 times higher than bulk g-C3N4. UV-vis diffuse reflectance spectrum, valence band, band gap, and the steady-state and time-resolved photoluminescence spectroscopy have further confirmed that the photogenerated carriers of g-C3N4 were effectively separated and prolonged its lifetime, thus releasing more photoexcited electrons with high reduction ability to produce H2. The possible mechanism of preparation of 2D-2D WO3/g-C3N4 nanosheets via scCO2 in the reverse microemulsion system with one-pot method has been proposed. This work provides an efficient and green strategy to synthesize 2D-2D heterojunction for the utilization in solar-to-fuel conversion.