2D/2DBi2MoO6/g-C3N4S-schemeheterojunctionphotocatalystwithenhancedvisible-lightactivitybyAuloading

A novel 2D/2D Bi2MoO6/g-C3N4 step-scheme（S-scheme） composite by loading Au as cocatalyst was successfully fabricated using a photoreduction and hydrothermal route. The obtained Bi2MoO6/g-C3N4/Au photocatalysts were characterized by X-ray diffraction（XRD）, transmission electron microscope（TEM）,X-ray photo-electron spectroscopy（XPS）, UV–vis diffuse reflectance spectra（UV–vis）, Fourier transform infrared spectroscopy（FTIR）, photoluminescence（PL）, photocurrent response（I-t）, and electrochemical impedance spectroscopy（EIS）. The HRTEM images revealed that an intimate interface in composites were formed. The optimum photocatalytic activity of Rhodamine B degradation over Bi2MoO6/g-C3N4/Au was about 9.7 times and 13.1 times as high as those of Bi2MoO6 and g-C3N4, respectively. The notably improved photocatalytic activity of Bi2MoO6/g-C3N4/Au could be mainly ascribed to the abundant active sites and the enhanced separation efficiency of photogenerated carriers in Bi2MoO6/g-C3N4 S-scheme system. Notably, Au nanoparticles could act as a co-catalyst to further promote electron transfer and separation from the conduction band of g-C3N4. Additionally, a possible step-scheme photocatalytic reaction mechanism of Rh B degradation over Bi2MoO6/g-C3N4/Au was tentatively proposed. PL and transient photocurrent analysis implied that Bi2MoO6/g-C3N4/Au photocatalysts possessed the lower recombination rate of photogenerated carriers compared with pure Bi2 MoO6 and g-C3N4, respectively. The present work is expected to provide useful information in designing 2D/2D S-scheme heterojunction photocatalysts.