Kebin Zhou

Chinese Academy of Sciences, Peping, Beijing, China

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Publications (38)191.76 Total impact

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    ABSTRACT: Cerium oxide nanoparticles (nano-CeO₂) have been reported to cause damage and apoptosis in human primary hepatocytes. Here, we compared the toxicity of three types of nano-CeO₂ with different nanocrystal morphologies (cube-, octahedron-, and rod-like crystals) in human hepatocellular carcinoma cells (HepG2). The cells were treated with the nano-CeO₂ at various concentrations (6.25, 12.5, 25, 50, 100 μg/mL). The crystal structure, size and morphology of nano-CeO₂ were investigated by X-ray diffractometry and transmission electron microscopy. The specific surface area was detected using the Brunauer, Emmet and Teller method. The cellular morphological and internal structure were observed by microscopy; apoptotic alterations were measured using flow cytometry; nuclear DNA, mitochondrial membrane potential (MMP), reactive oxygen species (ROS) and glutathione (GSH) in HepG2 cells were measured using high content screening technology. The scavenging ability of hydroxyl free radicals and the redox properties of the nano-CeO₂ were measured by square-wave voltammetry and temperature-programmed-reduction methods. All three types of nano-CeO₂ entered the HepG2 cells, localized in the lysosome and cytoplasm, altered cellular shape, and caused cytotoxicity. The nano-CeO₂ with smaller specific surface areas induced more apoptosis, caused an increase in MMP, ROS and GSH, and lowered the cell's ability to scavenge hydroxyl free radicals and antioxidants. In this work, our data demonstrated that compared with cube-like and octahedron-like nano-CeO₂, the rod-like nano-CeO₂ has lowest toxicity to HepG2 cells owing to its larger specific surface areas.
    Preview · Article · Sep 2015 · International Journal of Environmental Research and Public Health
  • Hongyi Tan · Jin Wang · Shuzhen Yu · Kebin Zhou
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    ABSTRACT: To eliminate indoor formaldehyde (HCHO) pollution, Pd/CeO2 catalysts with different morphologies of ceria support were employed. The palladium nanoparticles loaded on {100}-faceted CeO2 nanocubes exhibited much higher activity than those loaded on {111}-faceted ceria nanooctahedrons and nanorods (enclosed by {100} and {111} facets). The HCHO could be fully converted into CO2 over the Pd/CeO2 nanocubes at a GHSV of 10 000 h-1 and a HCHO inlet concentration of 600 ppm at ambient temperature. The prepared catalysts were characterized by a series of techniques. The HRTEM, ICP-MS and XRD results confirmed the exposed facets of the ceria and the sizes (1-2 nm) of the palladium nanoparticles with loading amounts close to 1%. According to the Pd 3d XPS and H2-TPR results, the status of the Pd-species was dependent on the morphologies of the supports. The {100} facets of ceria could maintain the metallic Pd species rather than the {111} facets, which promoted HCHO catalytic combustion. The Raman and O 1 s XPS results revealed that the nanorods with more defect sites and oxygen vacancies were responsible for the easy oxidation of the Pd-species and low catalytic activity.
    No preview · Article · Jun 2015 · Environmental Science & Technology
  • Jin Wang · Hongyi Tan · Shuzhen Yu · Kebin Zhou
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    ABSTRACT: Well-defined {100}-faceted ceria nanocube-supported gold nanoclusters with various morphologies, including individual atom, monolayer, multilayer and nanoparticle, have been synthesized and systematically investigated combined with density functional theory calculations. A strong morphological effect of gold clusters on the reactivity of ceria surface oxygen has been identified. The reducibility and CO oxidation activities of Au/CeO2 catalysts increased significantly as the morphology of the gold clusters changed from single atoms to monolayer, then to multilayer then nanoparticles. It was revealed that up to a bilayer of gold clusters were needed for desirable catalytic performance in the Au/CeO2 system. The transfer of electrons from gold clusters to the surface Ce-O groups of ceria and strong Au-Au interactions play significant roles in determining the reducibility of surface oxygen of CeO2.
    No preview · Article · May 2015 · ACS Catalysis
  • Shuzhen Yu · Hongyi Tan · Jin Wang · Xin Liu · Kebin Zhou
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    ABSTRACT: Two types of monolith high porosity super-macroporous polystyrene materials had been controlled synthesized from water-in-oil Pickering emulsions. The first type, closed-cell high porosity (up to 91 %) super-macroporous (ca 500 µm) polystyrene materials (CPPs) was prepared by employing amphiphilic carbonaceous microspheres (CMs) as high internal phase emulsion stabilizer without any inorganic salts or further modifying the wettability of the particles. The second type, hierarchical porous polystyrene materials with highly interconnected macropores (IPPs) was constructed from emulsions stabilized simultaneously by CM particles and a little amount of surfactants. Both types of these monolith porous polystyrene materials possessed excellent mechanical strength. The CPPs were used as absorbents for oil-water separation and high absorption capacity and absorption rate for oils were realized, which was attributed to their porosity structure and the swelling property of the polystyrene. While the IPPs were highly permeable for gases due to their interconnected macropores.
    No preview · Article · Mar 2015 · ACS Applied Materials & Interfaces
  • Yan Zhang · Kebin Zhou · Yanwu Zhai · Fei Qin · Lulu Pan · Xin Yao
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    ABSTRACT: Due to the conflicting reports on the antioxidant activity of cerium oxide nanoparticles, much work has been done to explore the factors influencing the antioxidant activity of nano-CeO2. However, most of the research was focused on external factors rather than the intrinsic properties such as the exposed crystal planes of the material itself. Here, we synthesized three kinds of nano-CeO2 with different morphologies by a hydrothermal process. These materials showed antioxidant ability in the following order: nanoparticles < nanobars < nanowires. The probable reason for this distinction is due to the difference in their exposed crystal planes. Nanoparticles mainly expose the stable plane (111), while nanobars favor to expose the active plane (110) and the more active plane (100). Nanowires expose the same lattice planes as nanobars but show a higher ratio of (100)/(110) due to their longer and thinner structures. The vacancy formation energy of the (100) and (110) planes is lower than that of the (111) plane, and the Ce4+/Ce3+ recycle is easier for nanobars and nanowires than that for nanoparticles, which results in an improved antioxidant activity. Nanowires expose a higher ratio of (100)/(110), thus its antioxidant activity is better than that of nanobars. This result may be helpful for further understanding of the mechanism of the antioxidant activity of nano-CeO2.
    No preview · Article · Oct 2014 · RSC Advances
  • Zhibin Zhu · Hongyi Tan · Jin Wang · Shuzhen Yu · Kebin Zhou
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    ABSTRACT: A series of amphiphilic carbonaceous microspheres-supported Pd catalysts have been prepared and their performances for the hydrodeoxygenation of vanillin have been investigated in both a pure aqueous phase and in water–oil biphasic systems. The wettability of the catalyst could be facilely tuned by adjusting the hydrothermal treatment temperature during the synthesis of the carbonaceous microspheres or by a post-treatment process in alkaline solution. In the aqueous phase reactions, the more hydrophilic the catalyst, the more active it was for the hydrodeoxygenation of vanillin. And the wettability of the support affects the activity through the interaction between the catalysts and substrates/products. In the case of a water–oil biphase, the wettability of the support played a key role in forming Pickering emulsions. It was found that the selectivity of the hydrodeoxygenation reactions was determined by the type of Pickering emulsion and high selectivity of p-creosol could be achieved in the water-in-oil emulsion systems.
    No preview · Article · Apr 2014 · Green Chemistry
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    ABSTRACT: Clean gold surface is inactive toward H2, however, computations, aided by experiments, reveal that gold surface could serve as a Lewis acid coupling with Lewis bases (e.g. imine and nitrile) to construct effective frustrated Lewis pairs (FLPs) to activate H2 and subsequently to achieve hydrogenation of small imines and nitriles. The Lewis base-coupled Au FLPs avoid tight adsorption of Lewis bases to gold surface via repulsion between nitrogen lone pair and the filled d-band electrons of the gold surface. This is different from the normal FLPs that use sterically demanding groups or a molecular scaffold to prevent formation of stable Lewis acid-base complexes. The enhanced reactivity of the gold surface toward H2 is due to the synergetic catalytic effects of Lewis acid (Au surface) and the coupled Lewis base (imine or nitrile), which is supported by projected density of states (PDOS) analyses. Among Cu, Ag and Au surfaces, Au surface exhibits such reactivity most significantly, because Au is much more electronegative than Cu and Ag. The study enriches the FLP chemistry by adding a new type (heterogeneous) of FLPs and reveals a new reaction mode for gold surface.
    No preview · Article · Mar 2014 · Chemical Science
  • Lei Wang · Dan Yang · Jin Wang · Zhibin Zhu · Kebin Zhou
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    ABSTRACT: Au/Mg(OH)2 catalysts with two different sizes (4 and 14 nm) of Au nanoparticles (NPs) have been prepared by depositing pre-fabricated Au NPs onto Mg(OH)2 nanosheets (NSs). It was found that 14 nm Au NPs supported on Mg(OH)2 exhibited unexpected activity for CO oxidation at ambient temperature that could be comparable with those of Au NPs of 4 nm. The Mg(OH)2 support was suggested to be responsible for the observed catalytic activity of larger gold supported catalysts.
    No preview · Article · Jun 2013 · Catalysis Communications
  • Lei Wang · Gang Lu · Dan Yang · Jin Wang · Zhibin Zhu · Zhixiang Wang · Kebin Zhou
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    ABSTRACT: Baby face: Interface engineering of ceria‐supported Au catalysts was achieved by a combination of DFT calculations and synthetic techniques. The reducibility of the Au/ceria catalysts was determined by the interfacial AuOCen structures.
    No preview · Article · Jun 2013 · ChemCatChem
  • Yanwu Zhai · Kebin Zhou · Ying Xue · Fei Qin · Limei Yang · Xin Yao
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    ABSTRACT: Nanoceria has been demonstrated as a potential antioxidative nano-drug. However, its short residence time in the body, toxic solvents involved in the synthesis processes, and especially the poor water solubility hinder its potential clinical applications. In this work, water-soluble chitosan-coated nanoceria particles (CNPs) are synthesized by a facile wet chemical route. The molar weight (MW) and concentration of chitosan do not affect the particles' size and the antioxidative activity of the CNPs over a wide range, and the mechanism is explored further. The behavior of CNPs over time and with a change of pH value were also examined. The CNPs reveal excellent antioxidative activity and stability over seven months at room temperature, and importantly, chitosan widens the pH range for the stable existence of water-soluble nanoceria. As a result, including its inherent advantages of wide availability, non-toxicity, biocompatibility and biodegradability, chitosan can also present the nanoceria with good water-solubility without interfering with its antioxidative activity. In other words, chitosan can enlarge the nanoceria stability over a higher pH range. These factors show the advantages of chitosan as a coating layer, promising the further application of nanoceria in biomedical and biotechnological fields.
    No preview · Article · Apr 2013 · RSC Advances
  • Lei Wang · Qingfen Luan · Dan Yang · Xin Yao · Kebin Zhou
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    ABSTRACT: Here, we investigated the interactions between nanorods (NRs) of Ce(OH)3 and CeO2 and the redox protein hemoglobin (Hb) by electrochemical methods combined with Electron Paramagnetic Resonance (EPR) spectroscopy. It was found that Ce(OH)3 NRs, with strong electron-donating ability, were able to conjugate with the aromatic residues in Hb, and were more efficient in the preferred stabilization of Feα.
    No preview · Article · Apr 2013 · RSC Advances
  • Ying Xue · Yanwu Zhai · Kebin Zhou · Lei Wang · Haina Tan · Qingfen Luan · Xin Yao
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    ABSTRACT: Cerium oxide (CeO(2)) nanoparticles display excellent antioxidant properties by scavenging free radicals. However, some studies have indicated that they can cause an adverse response by generating reactive oxygen species (ROS). Hence, it is important to clarify the factors that affect the oxidant/antioxidant activities of CeO(2) nanoparticles. In this work, we report the effects of different buffer anions on the antioxidant activity of CeO(2) nanoparticles. Considering the main anions present in the body, Tris-HCl, sulfate, and phosphate buffer solutions have been used to evaluate the antioxidant activity of CeO(2) nanoparticles by studying their DNA protective effect. The results show that CeO(2) nanoparticles can protect DNA from damage in Tris-HCl and sulfate systems, but not in phosphate buffer solution (PBS) systems. The mechanism of action has been explored: cerium phosphate is formed on the surface of the nanoparticles, which interferes with the redox cycling between Ce(3+) and Ce(4+). As a result, the antioxidant activity of CeO(2) nanoparticles is greatly affected by the external environment, especially the anions. These results may provide guidance for the further practical application of CeO(2) nanoparticles.
    No preview · Article · Aug 2012 · Chemistry - A European Journal
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    ABSTRACT: It is still a challenge to develop green, simple and effective approaches to prepare aromatic iodides. Herein, a novel and green strategy for the direct mono‐iodination of aromatic compounds starting with molecular iodine has been developed. The strategy uses ceria nanocrystals to decompose hydrogen peroxide, giving hydroxyl radicals which are demonstrated experimentally and computationally to be crucial to promote the iodinations.
    No preview · Article · Mar 2012 · Advanced Synthesis & Catalysis
  • Kebin Zhou · Yadong Li
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    ABSTRACT: Using bottom-up chemistry techniques, the composition, size, and shape in particular can now be controlled uniformly for each and every nanocrystal (NC). Research into shape-controlled NCs have shown that the catalytic properties of a material are sensitive not only to the size but also to the shape of the NCs as a consequence of well-defined facets. These findings are of great importance for modern heterogeneous catalysis research. First, a rational synthesis of catalysts might be achieved, since desired activity and selectivity would be acquired by simply tuning the shape, that is, the exposed crystal facets, of a NC catalyst. Second, shape-controlled NCs are relatively simple systems, in contrast to traditional complex solids, suggesting that they may serve as novel model catalysts to bridge the gap between model surfaces and real catalysts.
    No preview · Article · Jan 2012 · Angewandte Chemie International Edition
  • Kebin Zhou · Yadong Li
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    ABSTRACT: Mithilfe von Bottom-Up-Verfahren können die Zusammensetzung, Größe und Form jedes beliebigen Nanokristalls gleichmäßig gesteuert werden. Die Erforschung formkontrollierter Nanokristalle hat gezeigt, dass die katalytischen Eigenschaften dieser Materialien wegen ihrer wohldefinierten Kristallflächen nicht nur von der Größe, sondern auch von der Form der Nanokristalle bestimmt werden. Diese Erkenntnis ist für die moderne Heterogenkatalyseforschung von großer Bedeutung: Erstens könnte damit eine rationale Synthese von Katalysatoren ermöglicht werden, da sich die gewünschte katalytische Aktivität und Selektivität mithilfe einer einfachen Regulierung der Größe (d. h. der exponierten Kristallflächen) des Nanokristalls einstellen lassen. Zweitens sind formkontrollierte Nanokristalle einfachere Systeme als herkömmliche, komplexe Festkörper und könnten daher als neuartige Modellkatalysatoren die Lücke zwischen Modelloberflächen und realen Katalysatoren schließen.
    No preview · Article · Jan 2012 · Angewandte Chemie
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    ABSTRACT: Rheological properties of cotton pulp dissolved in 1-butyl-3-methylimidazolium chloride ([Bmim]Cl) solutions were characterized using an advanced rheometer. The complex viscosity, dynamic modulus, and shear viscosity at different temperature were studied. In the steady shear measurements, all the solutions show a shear-thinning behavior at high shear rates. The complex viscosity as a function of frequency was fitted by extended Carreau-Yasuda model. In all cotton pulp/[Bmim]Cl solutions, the complex dynamic viscosity (eta*) and steady shear viscosity (eta(a)) followed the Cox-Merz rule only at lower frequency. The effects of tested temperature on viscosity and viscoelastic behavior of the solutions were also investigated. The value of activation energy for the dissolution of cotton pulp in ionic liquids was 65.28 kJ/mol at the concentration of 10 wt% and was comparable with the ones for the dissolution of cellulose in NMMO. POLYM. ENG. SCI., 51: 2381-2386, 2011. (C) 2011 Society of Plastics Engineers
    Full-text · Article · Dec 2011 · Polymer Engineering and Science
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    ABSTRACT: Dissolution and regeneration of cotton pulp using ionic liquids as solvent was investigated. The physicochemical properties of the regenerated cellulose films have been characterized by scanning electron microscopy, X-ray diffractometer, infrared spectrometric analyzer, differential scanning calorimeter, and thermogravimetric analysis instrument. The rheological properties of cotton pulp dissolved in ionic liquids have been investigated by steady shear and oscillatory shear measurements. The influences of experimental parameters, such as the reaction temperature, additives on the solubility and degree of polymerization (DP) of regenerated cellulose were also studied. The results show that 1-butyl-3-methylimidazolium chloride ([bmim]Cl) was a good solvent to dissolve cotton pulp and the solubility can reach 13wt% at 90°C, but the DP remarkably decreased from 510 to 180 within 7h. It was found that additive N-methylimidazole can effectively minimize DP loss of the regenerated cellulose, which can attribute to the fact that in the mixture of [bmim]Cl and NMI solution, the β-1,4-glycosidic bond of the cellulose chains cannot be broken because of the relative low concentration of Cl−. In the steady shear measurement, all the solutions show a shear thinning behavior at high shear rates. In addition, a mechanism of the dissolution of cellulose in [bmim]Cl was proposed.
    Full-text · Article · Nov 2011 · Materials Chemistry and Physics
  • Hongyi Tan · Peng Zhang · Lei Wang · Dang Yang · Kebin Zhou
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    ABSTRACT: Multifunctional amphiphilic hollow carbonaceous spheres assembled into Pickering emulsions exhibit reversible pH-dependent phase-transfer behavior and can efficiently catalyze water/oil biphasic reactions, facilitating the recycling of the catalysts and separation of the products.
    No preview · Article · Nov 2011 · Chemical Communications
  • Ying Xue · Qingfen Luan · Dan Yang · Xin Yao · Kebin Zhou
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    ABSTRACT: Cerium oxide (CeO2) nanoparticles have been considered as excellent antioxidants and have become a focus of numerous studies. However, the mechanism behind the antioxidant role in the complex biological system has not been well-understood. In this work, direct evidence for the hydroxyl radical (•OH) scavenging activity of CeO2 nanoparticles was established by a simple photometric system in vitro. When methyl violet (MV) reacted with hydroxyl radical, the absorbance change indicated the hydroxyl radical level. The presence of CeO2 nanoparticles protected MV by competitively reacting with the •OH, so their hydroxyl radical scavenging activity was directly seen through the absorbance change. This activity was also proved to be size-dependent and was believed to have a close correlation with Ce3+ at the surface of the particles.
    No preview · Article · Feb 2011 · The Journal of Physical Chemistry C
  • Qingfen Luan · Kebin Zhou · Haina Tan · Dan Yang · Xin Yao
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    ABSTRACT: Gold nanoparticles (Au-NPs) are usually used to amplify surface plasmon resonance (SPR) signals, however, the serious nonspecific adsorption has largely limited their practical applications. Here, we developed a novel Au-NPs enhanced biosensor without the effect of nonspecific adsorption: cutting Au-NPs off from the biosensor surface by RsaI endonuclease. In order to further improve the sensitivity, the probe DNA was designed specially. After the cleavage reaction, the residual probe DNA formed hairpin structure, which also resulted in a great change in SPR dip shift. Then, with the coaction of Au-NPs and conformation change of probe DNA, the SPR signal was amplified greatly. Using this method, we monitored the process of DNA cleavage in real-time and achieved a detection level of 5×10(-8) M. Moreover, the result of X-ray photoelectron spectroscopy (XPS) experiment further confirmed that large nonspecific adsorption existed. However, because SPR recorded a process in which the Au-NPs were cut off, the serious nonspecific adsorption did not affect the experimental result.
    No preview · Article · Jan 2011 · Biosensors & Bioelectronics

Publication Stats

2k Citations
191.76 Total Impact Points


  • 2002-2015
    • Chinese Academy of Sciences
      • School of Chemistry and Chemical Engineering
      Peping, Beijing, China
  • 2008-2014
    • Technical Institute of Physics and Chemistry
      Peping, Beijing, China
  • 2004-2006
    • Tsinghua University
      • Department of Chemistry
      Beijing, Beijing Shi, China