A novel ternary plasmonic Ag 3 VO 4 /AgBr/Ag hybrid photocatalyst was successfully fabricated via an in situ anion-exchange reaction between Ag 3 VO 4 and KBr, followed by light reduction. The obtained samples were characterized by X-ray diffraction, scanning electron microscopy, energydispersive X-ray spectroscopy, UV−visible diffuse-reflectance spectroscopy (UV−vis DRS), and X-ray photoelectron spectroscopy. The photocatalytic activities of obtained photocatalysts were measured by the degradation of Rhodamine B and methylene blue under visible-light irradiation (λ ≥ 400 nm). As-prepared Ag 3 VO 4 /AgBr/Ag plasmonic photocatalysts exhibit wide absorption in the visible-light region and display superior visible-light-driven photocatalytic activities in degradation of organic contamination compared with pristine Ag 3 VO 4 , Ag 3 VO 4 /AgBr, and AgBr/Ag. This enhanced photocatalytic activity is attributed to the synergistic effects between Ag 3 VO 4 /AgBr-based heterostructured semiconductor photocatalysis and the surface plasmon resonance (SPR) of Ag nanoparticles (NPs). On the basis of UV−vis DRS and valence band X-ray photoelectron spectroscopy, a possible mechanism of enhanced photocatalytic activity of Ag 3 VO 4 /AgBr/Ag is proposed; the vectorial electron transfer driven by the matching band potentials of AgBr and Ag 3 VO 4 and the SPR of Ag NPs contribute to its high photocatalytic activity and the improved stability. Therefore, the present study provides helpful insight into the design of novel and highly efficient visible-light photocatalysts in the future.

A heterostructured Ag3PO4/AgBr/Ag plasmonic photocatalyst was prepared by a rational in situ ion exchange reaction between Ag3PO4 micro-cubes and Br(-) in aqueous solution followed by photoreduction. The photocatalytic activities of obtained photocatalysts were measured by the degradation of methyl orange (MO) and methylene blue (MB) under visible light irradiation (λ≥ 400 nm). Compared to AgBr/Ag, Ag3PO4/AgBr heterocrystals and pure Ag3PO4 crystals, the heterostructured Ag3PO4/AgBr/Ag plasmonic photocatalysts exhibit much higher photocatalytic activity and stability. This enhanced photocatalytic activity suggests that the synergetic effects of the heterostructured Ag3PO4/AgBr/Ag and the strong SPR of Ag NPs on the surface result in the high efficiencies of the photocatalytic activity and the improved stability. With the assistance of Ag3PO4/AgBr/Ag heterostructures, only 8 min and 12 min are taken to completely decompose MO and MB molecules under visible-light irradiation, respectively. Furthermore, the photodegradation rate does not show an obvious decrease during ten successive cycles, indicating that our heterostructured Ag3PO4/AgBr/Ag plasmonic photocatalysts are extremely stable under visible-light irradiation.

In this work, we report the synthesis of Cd1-xZnxS zinc blende/wurtzite (ZB/WZ) heterophase nanojunctions with highly efficient charge separation by a solvothermal method in a mixed solution of diethylenetriamine (DETA) and distilled water. l-Cysteine was selected as a sulfur source and a protecting ligand for stabilization of the ZB/WZ homojunction. The optimal ternary chalcogenide Cd0.7Zn0.3S elongated nanocrystals (NCs) without any cocatalyst loading show very high visible light photocatalytic activity with H2 production efficiency of 3.13 mmol h(-1) and an apparent quantum efficiency of 65.7% at 420 nm. This is one of the best visible light photocatalysts ever reported for photocatalytic hydrogen production without any cocatalysts. The charge separation efficiency, having a critical role in enhancing photocatalytic activity for hydrogen production, was significantly improved. Highly efficient charge separation with a prolonged carrier lifetime is driven by the internal electrostatic field originating from the type-II staggered band alignment at the ZB/WZ junctions, as confirmed by steady and time-resolved photoluminescence spectra. Further, the strong binding between the l-cysteine ligand and Cd1-xZnxS elongated nanocrystals protects and stabilizes NCs; the l-cysteine ligand at the interface could trap holes from Cd1-xZnxS NCs, while photogenerated electrons transfer to Cd1-xZnxS catalytic sites for proton reduction. Our results demonstrate that Cd1-xZnxS ZB/WZ heterophase junctions stabilized by l-cysteine molecules can effectively separate charge carriers and achieve highly visible light photocatalytic hydrogen production. The present study provides a new insight into the design and fabrication of advanced materials with homojunction structures for photocatalytic applications and optoelectronic devices.