JOURNAL OF ALLOYS AND COMPOUNDS
·
2013
·
IF 2.39
Qin Li,Hui Li,Runming Wang,Guangfang Li,Hao Yang,Rong Chen
Size- and morphology-controlled zinc oxide (ZnO) micro-/nanostructures have been successfully synthesized via a facile and rapid microwave and ultrasonic wave combined method in HEPES solution (HEPES = 2-[4-(2-hydroxyethyl)-1-piperazinyl]ethanesulfonic acid). The as-prepared ZnO products are characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED) and UV–vis diffuse reflection spectroscopy (DRS). Various morphologies of ZnO products, including grenade-like, column-like, spindle-like, rod-like, shuttle-like and flower-like micro-/nanostructures are obtained, which are strongly dependent on Zn/HEPES moral ratio, pH value and Zn precursor. It is found that HEPES plays a crucial role in the formation of ZnO micro-/nanostructures with controllable size and morphology. The photocatalytic activities of the prepared ZnO micro-/nanostructures are evaluated by degradation of methylene blue (MB) under UV light irradiation, among which spindle-like ZnO microstructures exhibit superior photocatalytic activity compared with other ZnO products.
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JOURNAL OF ALLOYS AND COMPOUNDS
·
2014
·
IF 2.726
L.W. Wang,F. Wu,D.X. Tian,W.J. Li,L. Fang,C.Y. Kong,M. Zhou
In this paper, Na-doped ZnO (NZO) thin films with doping contents of 3–30 at.% were synthesized on quartz glass substrates by sol–gel spin coating method. The structure, morphology, optical transmittance and photoluminescence properties of NZO films were characterized by X-ray diffraction (XRD), field emission scanning electron microscope (FESEM), atomic force microscope (AFM), UV–VIS spectrometer and fluorescence spectrophotometer, respectively. The results showed that all the NZO thin films exhibit a strong preferential c -axis orientation with a hexagonal polycrystalline structure. An apparent increase in crystallinity was observed with the increasing Na content. The surface of the heavily Na doped samples (30 at.%) exhibits nanorods morphology. The RMS roughness changed from 16.219 nm to 53.072 nm with the increase of Na concentrations. As Na doping content increases to 24 at.%, the average transmittance was still larger than 62% in the visible range. The optical band gap initially increased and then decreased nearly linearly with the increase of Na content. The refractive index of NZO films in the visible range was found to increase gradually with increasing Na dopants. Room temperature photoluminescence (PL) spectra showed sharp ultraviolet emissions centered at 388 nm and broad green–yellow emissions (450–650 nm). The violet emission centered at 424 nm appeared in the spectra of 30 at.% NZO. In addition, it was found that the low Na doping concentration contributed to the enhancement of I NBE / I DLE .
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Journal of Materials Chemistry A
·
2014
·Vol. 2
·期 20
·7313-7318
·
IF 0
Ruosong Wang,Huaqiao Tan,Zhao Zhao,Guoqiang Zhang,Laiwen Song,Wenfei Dong,Zaicheng Sun
Nanostructured metal oxides such as ZnO and TiO2 have been extensively employed as self-cleaning coatings due to their large band gaps as well as their hydrophilic and photocatalytic properties. We have developed a simple hydrothermal method to coat thin TiO2 nanosheets with exposed (001) facets onto a ZnO nanorod array. The chemical stability of the ZnO nanorods was great improved due to the existence of the TiO2 layer. Owing to the porous structure of the ZnO@TiO2 nanorod arrays, this thin coating layer possesses anti-reflective properties. A transmittance improvement of ∼5% was observed for one-side coated FTO glass. This coating also exhibits good hydrophilic properties, after addition of the TiO2 nanosheets. More importantly, these ZnO@TiO2 nanorod arrays display excellent photocatalytic properties for the degradation of dye molecules, due to the heterojunction between the ZnO nanorods and TiO2 nanosheets. This heterojunction facilitates the charge separation of photo generated carriers. Based on the above features, the ZnO@TiO2 core/shell nanorod array film has many advantages as a self-cleaning coating.
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Scientific Reports
·
2015
·Vol. 5
·期 1
·1-8
·
IF 5.578
Li Shuying,Sun Zongzhao,Li Rui,Dong Minmin,Zhang Liyan,Qi Wei,Zhang Xuelin,Wang Hua
Multicolor ZnO quantum dots (QDs) were synthesized and further modified with hydrophobic hexadecyltrimethoxysilane (HDS) and then hydrophilic aminopropyltriethoxysilane (APS) bilayers, resulting in amine-functionalized ZnO@HDS@APS nanocomposites with tunable fluorescence from blue to green yellow. Systematic investigations verify that the resulting ZnO@HDS@APS could display extremely high stability in aqueous media and unexpectedly, dramatically-enhanced fluorescence intensities, which are about 10-fold higher than those of bare ZnO QDs. The feasibility of the as-prepared ZnO nanocomposites for blood, cell and tissue imaging was preliminarily demonstrated, promising the wide bio-applications for cell or tissue imaging, proteome analysis, drug delivery and molecular labeling.
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PubMed
高影响因子
Analytical Methods
·
2015
·Vol. 7
·期 21
·9340-9346
·
IF 1.821
Kewei Wang,Na Sun,Xinpan Li,Ruihua Zhang,Guangyue Zu,Jine Wang,Renjun Pei
This study reported the development of a p–n heterojunction photoelectrochemical biosensor using a G-quadruplex as the recognition system. The n-type ZnO nanorods and p-type BiOI nanoflakes were combined to form the heterostructure by in situ growth of BiOI attributed to a simple impregnating-hydroxylation method. This simple p–n heterojunction fabrication method could facilitate the development of rapid and sensitive visible light activated PEC sensors. In this study, the ZnO/BiOI photoelectrode showed a rapid photocurrent decrease in the presence of Pb2+ due to the electron withdrawing effect of hemin which bound with the G-quadruplex/Pb2+ complex. This PEC biosensor exhibited a good response following the concentration of Pb2+ in the range from 10 to 100 μM.
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ENZYME AND MICROBIAL TECHNOLOGY
·
2014
·
IF 2.966
Chuan-Yang Shang,Wei-Xun Li,Rui-Feng Zhang
ZnO nanowires were successfully introduced into a macroporous SiO 2 by in situ hydrothermal growth in 3D pores. The obtained composites were characterized by SEM and XRD, and used as supports to immobilize Candida antarctica lipase B (CALB) through adsorption. The high specific surface area (233 m 2 /g) and strong electrostatic interaction resulted that the average loading amount of the composite supports (196.8 mg/g) was 3–4 times of that of macroporous SiO 2 and approximate to that of a silica-based mesoporous material. Both adsorption capacity and the activity of the CALB immobilized on the composite supports almost kept unchanged as the samples were soaked in buffer solution for 48 h. The chiral resolution of 2-octanol was catalyzed by immobilized CALB. A maximum molar conversion of 49.1% was achieved with 99% enantiomeric excess of ( R )-2-octanol acetate under the optimal condition: a reaction using 1.0 mol/L ( R , S )-2-octanol, 2.0 mol/L vinyl acetate and 4.0 wt.% water content at 60 °C for 8 h. After fifteen recycles the immobilized lipase could retain 96.9% of relative activity and 93.8% of relative enantioselectivity .
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JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2016
·Vol. 27
·期 7
·6656-6664
·
IF 1.798
Lin Yibing,Lin Yu,Wu Jihuai,Zhang Xiaolong,Fang Biaopeng
In this study, after CdS quantum dots sensitized ZnO hierarchical spheres (ZnO HS), we used a simple process to deposit CdSe QDs on ZnO by spin-coating-based SILAR, and applied to photoanodes of quantum dots-sensitized solar cells. Before CdS and CdSe QDs deposition, the ZnO HS photoanodes were modified by Zn(CH 3 COO) 2 ·2H 2 O methanol solution to further enhance the open-circuit voltage and power conversion efficiency (PCE). The program of modifying photoanodes and the number of CdSe spin-SILAR cycles are evaluated on the optical and electrochemical properties of the cells. As a result, a high energy conversion efficiency of 2.49 % was obtained by using modified ZnO HS/CdS photoanode under AM 1.5 illumination of 100 mW cm −2 . And further decorated by the CdSe QDs, the ZnO HS/CdS/CdSe cell achieved a PCE of 5.36 % due to the modification of ZnO HS nanostructure, the enhanced absorption in the visible region, the lower recombination reaction and higher electron lifetime.
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ACS Applied Materials & Interfaces
·
2016
·
IF 7.145
Wenhu Yang,Jian Wang,Suibin Luo,Shuhui Yu,Haitao Huang,Rong Sun,Ching-Ping Wong
Overvoltage protection is becoming increasingly important because of miniaturization and multifunctionality of electronic devices. Flexible, easily processable materials with nonlinear and reversible I–V behavior are highly desired. In this study, hybrid nanoparticles of ZnO-decorated carbon nanotubes (CNT–ZnO) were synthesized via a sol–gel hydrothermal process employed in an epoxy matrix to prepare composites. Microstructure analysis demonstrated that ZnO nanoparticles were well-bonded to the surface of CNT. The CNT–ZnO/epoxy composites exhibited nonlinear I–V behavior under increasingly applied voltage with a nonlinear coefficient of 5.01 (10 wt % filler loading). More importantly, the composites possessed excellent reversibility from dielectric to conductor and vise versa in the recycling of increase and decrease of applied electric field, in contrast to the poor recoverability of pure CNT-filled epoxy. The mechanism of the nonlinear I–V behavior and reversibility was investigated and discussed. A simple circuit was fabricated, which verified well the protection function of the CNT–ZnO/polymer composites.
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ACS Sustainable Chemistry & Engineering
·
2017
·
IF 5.951
Quan-Yong Cheng,Xu-Pei An,Yi-Dong Li,Cai-Li Huang,Jian-Bing Zeng
Conventional superhydrophobic materials for oil/water separation were usually prepared from nondegradable and nonrenewable resources, which would not only increase resource crisis but also cause environmental pollution after discarding. In this study, we report a renewable and biodegradable superhydrophobic material, which was fabricated via a two-step curing dip-coating method and was composed of cellulosic filter paper or fabric, cured epoxidized soybean oil (CESO), ZnO, and stearic acid (STA) as the substrate, adhesive, rough structure, and low energy modifier, respectively. The CESO combined ZnO nanoparticles with cellulosic substrate tightly to show excellent stability when suffering from immersing in water and oil for 7 days without losing superhydrophobicity. When the superhydrophobic coating was constructed onto the surface of cellulosic fabric, the material showed high separation efficiency with the values higher than 97% during separation of various oil/water mixtures. The sustainable and biodegradable superhydrophobic material may find potential application in efficient oil/water separation without creating material waste after throwing away.
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MATERIALS RESEARCH BULLETIN
·
2016
·
IF 2.435
Chong Yang,Jisheng Yu,Qingsong Li,Yingmin Yu
Monodisperse porous ZnO nanospheres were successfully fabricated through a facile and cost-effective polyol-mediated preparation approach, followed by annealing at 400 °C for 2 h. The photocatalytic activity of the ZnO products was evaluated by the decolorization of rhodamine B (RhB) solution under simulated sunlight irradiation. The effects of operational parameters on the photo-degradation reaction progress, including catalyst dosage, initial dye concentration, reaction temperature, initial pH value, and the addition of inorganic oxidants, transition-metal ions and inorganic anions were investigated in detail. In addition, reactive species in the oxidation of RhB solution were pinpointed by adding a series of scavengers into the photocatalytic reaction system and O 2 − were determined to be the main reactive species. A potential mechanism of photocatalysis of RhB under simulated sunlight irradiation is proposed. The catalyst is found to be reusable.
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ACS Applied Materials & Interfaces
·
2017
·
IF 7.504
Dandan Ma,Jian-Wen Shi,Yajun Zou,Zhaoyang Fan,Xin Ji,Chunming Niu
A novel CdS/ZnO heterojunction constructed of zero-dimensional (0D) CdS quantum dots (QDs) and two-dimensional (2D) ZnO nanosheets (NSs) was rationally designed for the first time. The 2D ZnO NSs were assembled into ZnO microflowers (MFs) via an ultrasonic-assisted hydrothermal procedure (100 °C, 12 h) in the presence of a NaOH solution (0.06 M), and CdS QDs were deposited on both sides of every ZnO NS in situ by using the successive ionic-layer absorption and reaction method. It was found that the ultrasonic treatment played an important role in the generation of ZnO NSs, while NaOH was responsible to the assembly of a flower-like structure. The obtained CdS/ZnO 0D/2D heterostructures exhibited remarkably enhanced photocatalytic activity for hydrogen evolution from water splitting in comparison with other CdS/ZnO heterostructures with different dimensional combinations such as 2D/2D, 0D/three-dimensional (3D), and 3D/0D. Among them, CdS/ZnO-12 (12 deposition cycles of CdS QDs) exhibited the highest hydrogen evolution rate of 22.12 mmol/g/h, which was 13 and 138 times higher than those of single CdS (1.68 mmol/g/h) and ZnO (0.16 mmol/g/h), respectively. The enhanced photocatalytic activity can be attributed to several positive factors, such as the formation of a Z-scheme photocatalytic system, the tiny size effect of 0D CdS QDs and 2D ZnO NSs, and the intimate contact between CdS QDs and ZnO NSs. The formation of a Z-scheme photocatalytic system remarkably promoted the separation and migration of photogenerated electron–hole pairs. The tiny size effect effectively decreased the recombination probability of electrons and holes. The intimate contact between the two semiconductors efficiently reduced the migration resistance of photogenerated carriers. Furthermore, CdS/ZnO-12 also presented excellent stability for photocatalytic hydrogen evolution without any decay within five cycles in 25 h.
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CELLULOSE
·
2016
·Vol. 24
·期 1
·147-162
·
IF 3.195
Fu Feiya,Gu Jiayuan,Xu Xinyi,Xiong Qinxue,Zhang Yanyan,Liu Xiangdong,Zhou Jinping
A bioinspired mineralization route to directly prepare ZnO–cellulose nanocomposite (ZCN) films from a cellulose–NaOH/urea/zincate solution was demonstrated in this study. By adding non-acid coagulants, an inclusion complex consisting of NaOH, urea and zincate, which was bound to the cellulose molecules, was broken. As a result, the cellulose aggregates occurred, which simultaneously aided the mineralization of ZnO nanostructures at room temperature. The structure and properties of the ZCN films were characterized using FE-SEM, TEM, XRD, UV–Vis spectra, XPS, TG, tensile testing and photocatalytic activity tests. Through changing different coagulants, the content and mean size of ZnO in the ZCN films varied in the range of 10.8–14.9 wt% and 56.8–146.8 nm, respectively. Owing to good interfacial interaction, the ZCN films displayed good mechanical and excellent photocatalytic properties. The mechanical strength and elongation at break of the ZCN films attained 46.7 MPa and 6.4 %, respectively. The degradation efficiency of rhodamine B reached 99.3 % within 50 min under UV light and only showed a slight decrease after three cycles. The cellulose-mediated bioinspired approach was expected to introduce a method for preparing functional cellulose-based materials under mild conditions for various niche applications.
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