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Novel Z-scheme type MoO 3 -g-C 3 N 4 composites photocatalysts were prepared with a simple mixingcalcination method, and evaluated for their photodegradation activities of methyl orange (MO). The optimized MoO 3 -g-C 3 N 4 photocatalyst shows a good activity with a kinetic constant of 0.0177 min À1 , 10.4 times higher than that of g-C 3 N 4 . Controlling various factors (MoO 3 -g-C 3 N 4 amount, initial MO concentration, and pH value of MO solution) can lead to the enhancement of the photocatalytic activity of the composite. Only MoO 3 and g-C 3 N 4 are detected with X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) spectra. N 2 adsorption and UV-vis diffuse reflectance spectroscopy (DRS) results suggest that the addition of MoO 3 slightly affects the specific surface area and the photoabsorption performance. The transmission electron microscopy (TEM) image of MoO 3 -g-C 3 N 4 indicates a close contact between MoO 3 and g-C 3 N 4 , which is beneficial to interparticle electron transfer. The high photocatalytic activity of MoO 3 -g-C 3 N 4 is mainly attributed to the synergetic effect of MoO 3 and g-C 3 N 4 in electron-hole pair separation via the charge migration between the two semiconductors. The charge transfer follows direct Z-scheme mechanism, which is proven by the reactive species trapping experiment and the cOH-trapping photoluminescence spectra.

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The present work was designed to synthesize Ag/KNbO 3 nanocomposite for efficient photocatalytic conversion of N 2 to NH 3 . KNbO 3 was prepared in a low KOH concentration solution at 260 °C, while Ag nanoparticles (NPs) were loaded on KNbO 3 by a photodeposition procedure. The as-synthesized nanocomposite presented excellent performance in photocatalytic N 2 fixation. Under simulated sunlight, the NH 3 generation rate reaches 385.0 μmol•L −1 g −1 •h −1 , which is 4 times higher than that of pure KNbO 3 . Additionally, the Ag/KNbO 3 composite also showed good photoactivity under visible light. Multiple techniques, including XRD, Raman, XPS, SEM, TEM, DRS, PL, EIS, PC, and LSV, were performed to reveal the origin of the high performance. The results indicated that a low KOH concentration is beneficial to formation of nanosize KNbO 3 , while a high hydrothermal temperature endowed KNbO 3 high crystallinity which boosted the bulk charge separation. The Ag NPs' decoration further increased the surface separation of charge carriers via trapping the electrons from KNbO 3 . The significantly elevated efficiency in charge separation is believed to be the origin of the high performance of the Ag/KNbO 3 composite. Additionally, the surface plasmon resonance effect of Ag NPs also awarded the composite the capability in absorbing visible light, which resulted in its visible-light-driven photocatalytic activity. Interestingly, under simulated sunlight, a competition between the photosensitization mechanism and the electron-trapping mechanism existed, and the latter dominated the photocatalytic process on Ag/KNbO 3 . Besides the photocatalytic N 2 fixation, the Ag/KNbO 3 composite also performed well in photocatalytic H 2 evolution and RhB degradation, indicating its great potential in practical photocatalytic application.

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A novel Bi2S3/KTa0.75Nb0.25O3 (KTN) heterojunction nanocomposite was prepared through a simple two-step hydrothermal method and primarily applied in the photocatalytic and piezocatalytic N2 fixation. Bi2S3 closely adhered to the surface...

A ZrO2/g-C3N4 composite was prepared by directly heating a ZrO2–melamine mixture and showed excellent activity in rhodamine photodegradation.