Ag2S/Ag2WO4 composite microrods,with lengths of 0.2-1μm and diameters of 20-30 nm,were fabricated by a facile sonochemical route.The as-synthesized products were intensively investigated by a series of physicochemical characterizations,such as N2 physical adsorption,X-ray diffraction,scanning electron microscopy,transmission electron microscopy,Fourier transform infrared spectroscopy,diffuser reflectance spectroscopy,X-ray photoelectron spectroscopy,photoluminescence spectroscopy and photocurrent response measurements.Ultrasonic irradiation yields an obvious improvement in the photocatalyst texture,for example,an increase in crystallinity and surface area.Moreover,sonochemically fabricated Ag2S/Ag2WO4 microrods display strong visible light absorption and a high transient photocurrent response.The produced intimate Ag2S/Ag2WO4interface between Ag2S and Ag2WO4 crystal phases largely promotes the separation of photogenerated holes and electrons.High photocatalytic activity and stability were obtained over Ag2S/Ag2WO4composite microrods.The dye degradation rate constant of Ag2S/Ag2WO4 was 4.7 times and 29.8times higher than that of bare Ag2WO4 and Ag2S,respectively.
A series of La/Ce-codoped Bi2O3 composite photocatalysts were fabricated via hydrothermal–calcination process. The as-prepared products were intensively characterized by some physicochemical characterizations like N2 physical adsorption, X-ray powder diffraction（XRD）, scanning electron microscope（SEM）, transmission electron microscope（TEM）, UV–Vis diffuse reflectance（UV–Vis DRS）, Fourier transform infrared spectroscopy（FT-IR）,photoelectrochemical measurements, and photoluminescence（PL） spectroscopy. The characterization results indicated that La and Ce doping induced obvious crystal phase transformation in Bi2O3, from monoclinic to tetragonal phase. La and Ce codoping also gave rise to the obvious synergetic effects, e.g., the lattice contraction of Bi2O3, the decrease of crystal size and the increase of surface area. The photocatalytic performance of the prepared catalysts was evaluated by removal of dye acid orange II with high concentration under visible light irradiation. Results showed that La/Ce-codoped Bi2O3 displayed much higher photocatalytic performance than that of bare Bi2O3, single La or Ce doped Bi2O3 samples. The superior photocatalytic activity was mainly attributed to the improved texture and surface properties and the synergistic effects of La and Ce codoping on suppressing the recombination of photo-generated electrons（e^-） and holes（h~＋）.
