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The Bi2S3-modified ZnO nanowires (Bi2S3/ZnO) were prepared by the electrochemistry deposition and successive ionic layer adsorption and reaction and their photoelectrochemical cathodic protection performance was explored. Compared with that of pristine ZnO, the photo-response of the Bi2S3/ZnO heterostructure thin-film red shifted to the visible light range and their photocathodic protection for 304 stainless steel and Q235 carbon steel was improved under visible light. Furthermore, the enhanced mechanism was investigated systematically explored and it found that the appropriate energy level arrangement and the construction of heterojunction is responsible for the enhanced photocathodic protection performance. [ABSTRACT FROM AUTHOR]

Rational design of hierarchical photocatalysts for dye degradation and hydrogen production has been believed as a wise selection for pollution control and energy solution. Herein, we present the design and synthesis of Fe3O4@SiO2@ZnO–Ag core shell microstructures with different ZnO loading amounts. The structure, morphology, composition, optical and magnetic properties of the as-synthesized samples were investigated by several characterization techniques. Photocatalytic degradation of rhodamine B (RhB) and hydrogen evolution under UV light were selected to assess the impact of ZnO loading amount on photocatalytic activities. Photocatalytic results reveal that Fe3O4@SiO2@ZnO–Ag with 15.14 wt% ZnO loading amount shows the best photocatalytic property. The RhB degradation efficiency of this sample was 98.1% after 100 min of UV light exposure. Additionally, the hydrogen evolution rate of this sample was 183 μmol h−1 under UV light illumination. It is also worth noting that these core shell microspheres were endowed with outstanding magnetic response, excellent photocatalytic reusability and chemical stability. The core shell photocatalysts can maintain high efficiency after five-cycles of RhB photocatalytic degradation run. Such features mentioned above made heterostructure Fe3O4@SiO2@ZnO–Ag photocatalysts promising candidates in practical use for environmental and energy challenges. [ABSTRACT FROM AUTHOR]

ZnO nanorods@nanoflowers (quantum dots) hybrid nanostructures have been successfully fabricated by the spin coating method. The transmission electron micrograph (TEM) and field-emission scanning electron microscopy (FE-SEM) images showed that ZnO quantum dots (QDs) and ZnO nanoflowers (NFs) had been assembled on the surfaces of ZnO nanorods (NRs) or in the upper parts of the gaps between the rods. The morphology of ZnO nanoflowers was formed through a general route of zero-dimensional (0D)→2D→3D, controlling by sodium dodecyl sulfate (SDS) during the experiment. The blue-shifts of Raman and PL spectra were observed for the hybrid nanostructures at room temperature, which were explained by the quantum confinement effects. Compared with the photocatalytic activities of the samples, ZnO NRs@NFs showed enhanced photocatalytic performance for the degradation of RhB under UV radiation, which could be attributed to the special structural feature with an open and porous nanostructured surface layer and the surface defects. ZnO NRs@NFs would show a wider application for its particular porous morphology. [ABSTRACT FROM AUTHOR]

The ZnO nanorods/ZnSe nanosheets heterostructure had been successfully fabricated by the spin coating method. The evolution of the structural, optical and photocatalytic properties of the samples with different spin coating times was comprehensively investigated. The X-ray diffraction (XRD) patterns showed that the relative intensities of ZnSe peaks increased gradually with the increase of spin coating times, but the ZnO peaks were relatively suppressed, which had a good agreement with the results of Raman spectra. The scanning electron microscope (SEM) and transmission electron micrograph (TEM) images further confirmed that the ZnSe nanosheets (NSs) had been successfully assembled on the top surfaces of the ZnO nanorods (NRs) and in the upper parts of the gaps between the rods. At room temperature, the ZnO/ZnSe heterostructures exhibited a relatively suppressed UV emission together with a dramatically enhanced deep-level emission. In addition, the heterostructures exhibited remarkable photocatalytic activities. The type-II staggered band alignment and defects formed at the ZnO/ZnSe interfaces should be the key factors for improved photocatalytic performance, and the probable photocatalytic mechanism was discussed in detail. [ABSTRACT FROM AUTHOR]

The ternary ZnCdO ( x = 0, 0.2) thin films with wurtzite structure and highly (002)-preferred orientations were deposited on glass substrates by the direct current (dc) reactive magnetron sputtering method. The X-ray diffraction, X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), optical absorption spectra and photoluminescence (PL) were employed to investigate the structural and the optical properties in detail. The results indicated that as x varied from x = 0-0.2, the diffraction angle of the (002) peaks decreased from ~34.36° to ~33.38° and the lattice spacing increased from 0.260 to 0.268 nm. Moreover, the optical band-gap of the ZnCdO thin films with the wurtzite structure decreased from 3.20 eV at x = 0-2.70 eV at x = 0.2. Correspondingly, the near-band-edge PL was tuned in a wide visible region from ~393 to 467 nm. The chemical bonding states of Cd in ZnCdO alloy thin films were examined by XPS analysis. [ABSTRACT FROM AUTHOR]

The ZnO nanostructure is difficult to apply in sewage treatment because of its low photocatalytic efficiency, narrow spectrum response, high photogenerated carrier recombination rate, and difficult retrieval from aqueous solution. CuO coupling could improve both the absorption of visible light and photocatalytic performance of ZnO nanoparticles. In this paper, the ZnO/CuO hollow microspheres was fabricated by a self-assembly method without a template. The experimental results showed that ZnO/CuO hollow microspheres (4 μm) were successfully prepared via the hydrothermal method. CuO coupling greatly ameliorated the photocatalytic performance of ZnO microspheres under natural solar light or visible light, and the photodegrading rate in natural solar light was approximately 6 times greater than that of pure ZnO spheres. In addition, ZnO/CuO spheres showed good photocatalytic stability. The enhanced catalytic activity is associated with the reduced impedance of the ZnO sphere via CuO coupling, which promotes the separation of e−/h+ carriers and enlarges the spectrum response to visible light. • ZnO/CuO hollow microspheres were prepared in situ without a template. • The effective heterostructure of ZnO and CuO was constructed. • ZnO/CuO hollow microspheres possess superior catalytic activity under natural sunlight. • CuO coupling can reduce impedance and facilitate transfer charge carriers. [ABSTRACT FROM AUTHOR]

• ZnO nanorods/MXene (ZnO-MX) hybrids were fabricated by ultrasonic oscillation. • ZnO-MX hybrids composite displayed good photocatalytic hydrogen production property. • ZnO-MX hybrids composite exhibited very high photocatalytic activity and satisfactory recyclability under visible-light. MXene is a novel metal compound with narrow band gap and has been widely applied in energy storage, solar energy cells, and hydrogen production. A simple technique was used to attain MXene, and then the ZnO nanorods/MXene (ZnO-MX) hybrids were fabricated by ultrasonic oscillation. Experimental results illustrated that MXene sheets were decorated by ZnO nanorods, and the resultant ZnO-MX hybrids possessed higher removal ability of Rhodamine B (RhB) than pure ZnO nanorods, in which the removal efficient was 3.2 times as fast as pure ZnO nanorods (0.0077 min−1) under visible light irradiation. Additionally, the photocatalytic hydrogen production of ZnO nanorods was improved by MXene sheet significantly. The enhancement was because MXene sheet increased the surface area of ZnO nanorods and reduced the resistance of transferring photo-engendered carriers, indicating that MXene sheet can serve as suitable carrier for photocatalytic materials. [ABSTRACT FROM AUTHOR]

Efficient electron transfer process and excellent CO 2 adsorption capacity are of great significance for improving CO 2 photoreduction efficiency. 3D–0D ZnO/CsPbBr 3 S-scheme heterojunction hollow spheres were successfully prepared via a simple self-assembled process for efficient CO 2 photoreduction. Photocatalytic CO 2 reduction experiments showed that the ZnO/CsPbBr 3 had the excellent CO 2 photocatalytic conversion activity to CO, which was about 2.61 times higher than that of ZnO hollow micro-spheres and 1.9 times higher than that of pure CsPbBr 3 quantum dots (QDs). Photoelectrochemical characterization confirmed that the ZnO/CsPbBr 3 composite had good photoelectric conversion ability and carrier transfer ability, which was beneficial to the photocatalytic reaction. The suitable band gap structure and DFT calculation results showed that the formation of built-in electric field at the ZnO/CsPbBr 3 interface can greatly improve the S-scheme electron transfer ability, which can foster the CO 2 photoreduction. Besides, the introduction of 3D structure can improve the dispersion of CsPbBr 3 QDs and effectively enhance the CO 2 capture ability of the catalyst, which greatly promoted the CO 2 photoreduction reaction. The current work can present a novel S-scheme photocatalyst, which is looked forward to providing a certain perception into the advance of novel highly efficient CsPbBr 3 QDs-based photocatalysts for CO 2 resource utilization. [Display omitted] • 3D–0D ZnO/CsPbBr 3 S-scheme heterojunction catalyst has been prepared. • ZnO/CsPbBr 3 S-scheme heterojunction catalyst exhibite excellent CO 2 photoreduction performance. • 3D ZnO greatly improves the dispersion of 0D CsPbBr 3 and capture ability of CO 2. • The experiments and DFT calculation results confirm the S-scheme heterojunction. [ABSTRACT FROM AUTHOR]

CO 2 hydrogenation to methanol was investigated over Pd/ZnO/Al 2 O 3 , focusing on the influence of the preparation method, reduction temperature and Pd loading on the catalytic performance. The structure of each catalyst was thoroughly examined using various techniques. The results indicated that the methanol selectivity depended on the content of PdZn alloy, which changed dynamically with varying the preparation methods and pretreatment procedures of the catalysts. More specifically, the ratio of PdZn/Pd 0 in the bimetallic compound increased with the rise of the reduction temperature, which eventually led to the increase of methanol selectivity. Additionally, the EXAFS results revealed the presence of ZnO x modified Pd species when the Pd loading was decreased to be lower than 2 wt%. However, the CH 3 OH selectivity remained almost identical when the reactions were conducted under similar CO 2 conversions. Therefore, we conclude that both the PdZn alloy and Pd modified by ZnO x islands are the active sites for methanol synthesis from CO 2 hydrogenation. [ABSTRACT FROM AUTHOR]

ZnO/CuO microspheres are modified by graphene oxide through in-situ and two step methods, respectively. The effects of graphene oxide content and preparation method on the morphology, structure and photocatalytic properties of this heterostructure are investigated. Those results show that ZnO/CuO/GO (ZCGO) with uniform size and high catalytic activity can be obtained through in-situ preparation. When the content of GO is 6 mL, ZCGO have the best photocatalytic performance under sunlight. It can reduce 99% rhodamine B solution in 100 min, and the degradation rate is 1.4 times that of ZnO/CuO composites. The embedded GO sheet effectively reduces the resistivity and improves the photocurrent, which increases from 102 μ A/cm2 (ZnO/CuO) to 140 μ A/cm2 (ZCGO). [Display omitted] • The ZnO/CuO/GO heterostructure structure are prepared successfully through in situ hydrothermal method. • The photocatalytic performance of ZnO/CuO/GO heterojunction is significantly improved compared with ZnO/CuO. • The embedded GO sheet effectively reduces the resistivity and improves the photocurrent. Semiconductor photocatalysts are energy-saving, environmental-friendly and efficient, which have great potential in solving environmental pollution. In this paper, ZnO/CuO microspheres are modified by Graphene Oxide (GO) through in-situ and two-step methods, respectively. The effects of graphene oxide content and preparation method on the morphology, structure and photocatalytic properties of heterostructure microspheres are investigated. The results show that ZnO/CuO/GO (ZCGO) microspheres with uniform size and high catalytic activity can be obtained through in-situ preparation. When the content of GO is 6 mL, composites prepared through in-situ method have the best photocatalytic performance under sunlight. It can reduce 99% rhodamine B solution in 100 min, and the degradation rate is 1.4 times that of ZnO/CuO composites. The embedded GO sheet reduces the resistivity and improves the photocurrent which increases from 102 μA/cm2 (ZnO/CuO) to 140 μA/cm2 (ZCGO). Those results indicate ZCGO can serve as suitable carrier for photocatalytic materials. [ABSTRACT FROM AUTHOR]

Zinc oxide (ZnO) nanophotocatalyst is a promising candidate for degrading organic pollutants but has an extremely low photocatalytic activity under nature sunlight. In this work, flower-like MoS 2 quantum dots/ZnO (MQ/ZnO) nanospheres with the size of approximately 1.26 μm are prepared at low temperature. The resultant flower-like MQ/ZnO nanospheres displayed higher photocatalytic activity than pure ZnO nanospheres under natural sunlight and without stirring, with the decomposition rate of the MQ/ZnO composites approximately 3.3 times higher than that of the pure ZnO nanospheres. Furthermore, the introduction of MoS 2 QDs endowed ZnO nanospheres with optical memory ability. The enhanced sunlight-driven photocatalytic activity is dependent on the unique electrical properties of MoS 2 QDs and the synergistic effect between ZnO and MoS 2 QDs. [ABSTRACT FROM AUTHOR]

ZnO as a promising photocatalyst has gained much attention for the removal of organic pollutants from water. However, the main drawbacks of the relatively low photocatalytic activity and high recombination rate of photoexcited electron-hole pairs restrict its potential applications. Herein, a ternary ZnO/reduced graphene oxide (rGO)/polyanline (PANI) nanocomposite has been synthesized and used as the photocatalyst, characterized by TEM, SEM, X-Ray diffraction, FTIR and Raman. The ZnO/rGO(7 wt.%)/PANI(10 wt.%) photocatalyst shows an enhanced photocatalytic performance for the photodegradation of methyl orange with a maximum degradation efficiency of almost 100% within 60 min under UV light irradiation compared to pure ZnO (15%). This improvement is attributed to the rGO which effectively improves the ability to transfer the photoexcited electrons and the specific surface area of material, the PANI which increases the absorption of light and adsorption of dyes, and the synergistic effect among ZnO, rGO and PANI. [ABSTRACT FROM AUTHOR]

Highlights: [•] Ag-ZnO core-shell structure was obtained via a simple one-step solvothermal process. [•] The approach was simple, mild, low cost, reproducible and easy-to-handle. [•] The obvious enhancement of UV luminescent has been observed. [•] Effects of the calcining temperature to luminescence were investigated in detail. [Copyright &y& Elsevier]

Photographs of RhB degradation under natural sunlight at different time: (a) 1h, (b) 3h, and (c) 6h. Single crystalline ZnO nanorods were prepared by annealing zinc acetate, and ZnO nanorod membrane was fabricated using carbon fiber cloth (CF) as support. ZnO nanorods possess superior catalytic activity under natural sunlight and visible light. Furthermore, ZnO-CF membrane exhibits good catalytic activity and strong stability during the degradation process, which is conducive to the application in the actual sewage treatment of ZnO nanorods. • Single crystalline ZnO nanorods were prepared by annealing zinc acetate. • ZnO nanorod membrane was fabricated using carbon fiber cloth as support. • ZnO nanorods possess superior catalytic activity under natural sunlight. • ZnO nanorod membrane exhibits good catalytic activity and stability. To solve the low catalytic activity and recycling difficulty of ZnO nanomaterials, a simple and large-scale synthesized method was used to prepare single crystalline ZnO nanorods with visible light response, and then ZnO membrane was fabricated using carbon fiber (CF) cloth as support. The resultant ZnO nanorods were carried out with X-ray diffraction (XRD), Scanning electron microscope (SEM), Transmission electron microscope (TEM), Raman spectra, X-ray photoelectron spectroscopy (XPS), Ultraviolet spectrophotometer, and fluorescence spectrum. The experimental results display that the prepared ZnO nanorods own single crystalline structure and outstanding photocatalytic performance, which the removal time of all RhB is 15 min at UV light, 60 min at visible light and 100 min at natural sunlight, respectively. Moreover, ZnO nanorod membrane can completely remove RhB within 6 h under natural sunlight, meaning that the synthesized ZnO nanorods and ZnO nanorod membrane have potential industrial application prospect. [ABSTRACT FROM AUTHOR]