Yuyu Bu

Highly efficient photocatalytic performance of graphene-ZnO quasi-shell-core composite material.

In the present paper, the graphene-ZnO composite with quasi-shell-core structure was successfully prepared using a one-step wet chemical method. The photocatalytic Rhodamine B degradation property and the photoelectrochemical performance of the graphene-ZnO quasi-shell-core composite are dependent on the amount of graphene oxide that is added. When the amount of graphene oxide added is 10 mg, the graphene-ZnO quasi-shell-core composite possesses the optimal photocatalytic degradation efficiency and the best photoelectrochemical performance. An efficient interfacial electric field is established on the interface between the graphene and ZnO, which significantly improves the separation efficiency of the photogenerated electron-hole pairs and thus dramatically increases its photoelectrochemical performance. In addition to the excellent photocatalytic and photoelectrochemical properties, the electron migration ability of the grephene-ZnO quasi-shell-core composite is significantly enhanced due to the graphene coating on ZnO surface; therefore, this material has great potential for application as a substrate material to accept electrons in dye solar cell and in narrow bandgap semiconductor quantum dot sensitized solar cells.

High-efficiency photoelectrochemical properties by a highly crystalline CdS-sensitized ZnO nanorod array.

A ZnO nanorod array with comparatively long nanorods was successfully prepared on a Ti substrate by applying a hydrothermal method twice. CdS nanoparticles with high crystallinity were deposited onto the surface of ZnO nanorods through a galvanostatic electrodeposition method. CdS-sensitized ZnO nanorod arrays after being hydrothermally grown twice with the second growth time of 6 h possessed the best photoelectrochemical performance. The photoinduced current densities at a 0 V bias potential are 23.7 and 15.8 mA·cm(-2) under the illumination of simulated sunlight and visible light, respectively. The monochromatic incident photon-to-electron conversion efficiency values at the wavelength of 380-520 nm are in the range of 50-60%, which indicated its high photoelectric conversion efficiency. The contribution from visible light is significantly higher than that from UV light. The prepared photoanodes in the present work exhibit a potential application in photoelectrochemical hydrogen production from water reduction under sunlight.

Study of the promotion mechanism of the photocatalytic performance and stability of the Ag@AgCl/g-C3N4 composite under visible light

The Ag@AgCl/g-C3N4 composite was prepared by in situ fabricating Ag@AgCl on the surface of g-C3N4 using deposition–precipitation and subsequently photo-assisted reduction. Both the photocatalytic degradation performance and the photocatalytic degradation stability of the Ag@AgCl/g-C3N4 composite are significantly improved compared to g-C3N4 and Ag@AgCl composite. The Ag@AgCl/g-C3N4 composite can completely degrade RhB in 20 min under the illumination of visible light (λ > 420 nm). The Ag@AgCl/g-C3N4 composite can increase the light absorption intensity in the visible light region due to the surface plasmon resonance effect of Ag, resulting in a significant increase of the yields of the photogenerated electrons and holes. An effective heterojunction electric field was formed on the interface between g-C3N4 and Ag@AgCl, which significantly strengthened the separation efficiency of the photogenerated electrons and holes, leading to a significant promotion of the photocatalytic degradation performance.

Highly efficient photoelectrochemical anticorrosion performance of C3N4@ZnO composite with quasi-shell–core structure on 304 stainless steel

Carbon nitride@zinc oxide (C3N4@ZnO) composite with a quasi-shell-core structure was prepared in this work. The coating of C3N4 on ZnO significantly increases the photoelectrochemical anticorrosion performance of ZnO. When the amount of C3N4 added is 1 wt%, the C3N4@ZnO composite can provide the best photoelectrochemical anticorrosion capability for 304 stainless steel. This improved performance is attributed to the formation of an effective heterojunction electric field on the interface between C3N4 and ZnO, which improves the separation efficiency of the photogenerated electron-hole pairs, increases the lifetime of the photoinduced electrons, and enhances the photoelectrochemical anticorrosion performance of ZnO.

Dramatically enhanced photocatalytic properties of Ag-modified graphene-ZnO quasi-shell-core heterojunction composite material

Preparation of semiconductor heterojunction composites with special nanostructure is an effective way to enhance the photoelectric conversion efficiency of photocatalysts. In this work, the graphene–ZnO composite with quasi-shell–core structure was successfully prepared using a one-step wet chemical method. Silver nanoparticles are loaded onto the graphene–ZnO quasi-shell–core composite by photo-assisted reduction. Ag modification significantly improved the photocatalytic rhodamine B degradation capability of the graphene–ZnO quasi-shell–core composite and all of the rhodamine B dye was degraded by it only after 10 min of white light illumination. The graphene–ZnO composite with quasi-shell–core structure could effectively improve the separation efficiency of the electrons and holes photoinduced by the ZnO. Ag modification could accelerate the reduction processes of the photogenerated electrons and avoid the accumulation of electrons on graphene, resulting in the promotion of the photocatalytic performance of this composite.

Enhancement in Photoelectrochemical Efficiency by Fabrication of @MWCNT Nanocomposites

An enormous enhancement in the photo-to-current conversion efficiency over the nanocomposite material composed by BiVO4 on the surface of MWCNTs, with respect to electrode of pure BiVO4, was observed. The heterojunction formed between MWCNTs and nano-BiVO4 is beneficial for the separation of photogenerated electrons and holes, resulting in more electrons that are able to transport efficiently to the surface and therefore enhance the photoefficiency.

Graphene-modified BiMo0.03V0.97O4 thin-film photoanode for enhanced photoelectrochemical water splitting performance

In this study, graphene is coated on the surface of an Mo-doped BiMo0.03V0.97O4 (BiMoVO) film by galvanostatic reduction deposition. The BiMoVO/graphene (BiMoVO/G) thin-film photoanode exhibits the optimal photoelectrochemical performance with the graphene deposition time of 600 s. The photoinduced current density is 3.5 mA cm−2 at the bias potential of 1 V, which increases by approximately 2.3 times that of the BiMoVO thin-film photoanode. Moreover, the BiMoVO/G photoanode shows higher photoelectrochemical stability as well. The improvement of the photoelectrochemical properties is attributed to the graphene coating, which acts as the receptor of the photogenerated electrons from the BiMoVO film. Therefore, the photogenerated electrons can be rapidly transferred to the substrate through the graphene channel, enhancing the separation efficiency of the photogenerated electron-hole pairs and prolonging the lifetime of the photoinduced electrons.