APPLIED SURFACE SCIENCE
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2016
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IF 3.15
Zezhou Zhu,Jiani Qin,Min Jiang,Zhengxin Ding,Yidong Hou
Photocatalytic reduction of carbon dioxide can convert chemically inert carbon dioxide into useful chemical fuel in a mild manner. Herein, Ag-CdS nanocomposites were prepared by photodeposition method and examined for photocatalytic CO 2 reduction under visible light. Meanwhile, the nanocomposites were characterized by XRD, SEM, TEM, XPS, DRS and PL in detail. The results show that, the deposition of Ag improves the photocatalytic performance of CdS, especially in the selectivity of CO 2 -to-CO. The highest photocatalytic activity is achieved over 1.0 wt.% Ag/CdS, with an increase by 3 times in comparison to CdS. In this reaction system, Ag can serve as electron trap as well as active site for CO 2 reduction, which is probably responsible for the enhanced activity and selectivity of CO 2 to CO over Ag/CdS. The possible mechanism of CO 2 photoreduction over Ag/CdS was proposed in view of the abovementioned analysis.
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TRANSACTIONS OF NONFERROUS METALS SOCIETY OF CHINA
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2017
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IF 1.342
Li-li ZHENG,Xin-yan XIAO,Yang LI,Wei-ping ZHANG
TiO 2 /WS 2 /g-C 3 N 4 composite photocatalysts were synthesized by a liquid-exfoliation-solvothermal method. In this process, the WS 2 /g-C 3 N 4 nano-sheets were prepared by liquid-exfoliation method from the bulk WS 2 and C 3 N 4 in the alcohol system, and then the TiO 2 nanoparticles (NPs) grew on the WS 2 /g-C 3 N 4 nano-sheets by in-situ synthesized technique. The photocatalytic activity of the as-prepared samples was evaluated by photocatalytic degradation of methyl orange (MO). The results showed that the as-prepared samples exhibited higher photocatalytic activities as compared to the pure TiO 2 , g-C 3 N 4 and TiO 2 /g-C 3 N 4 composite. The enhanced photocatalytic activities of TiO 2 /WS 2 /g-C 3 N 4 photocatalysts could be attributed to the synergistic effect of heterostructure between TiO 2 NPs and WS 2 /g-C 3 N 4 nano-sheets, which could efficiently improve the separation of photogenerated electron/hole pairs and utilization efficiency of photons. The quenching tests of radicals indicated that ·O − 2 had crucial effect on degradation of MO, which demonstrated that ·O − 2 was the main active radical in photocatalytic reaction process.
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RSC Advances
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2017
·Vol. 7
·期 67
·42073-42082
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IF 3.108
Ling-Yuan Guo,Shu-Zhen Yan,Qiang Li,Qiao Xu,Xi Lin,Shan-Shan Qi,Shu-Qin Yu,Shuang-Lin Chen
Hypocrellin A (HA), a perihydroxylated polycyclic quinone isolated from the fungus of Shiraia bambusicola, exhibits a wide spectrum of biological activities in pre-clinical studies. However, poor water solubility is a major clinical constraint factor of HA, leading to unpredictable bioavailability. In this study, HA-loaded poly (lactic-co-glycolic acid) (PLGA) nanoparticles (PLGA/HA NPs) were prepared by the single-emulsion solvent-evaporation technique. Characterization of PLGA/HA NPs showed that HA was successfully encapsulated on the PLGA. The drug-loading content and encapsulation efficiency (EE) were 7.0% and 57.5%, respectively. The in vitro release profile demonstrated that HA was released more slowly from nanoparticles in pH 1.5 and pH 6.8 than in pH 7.4. Furthermore, the highest solubility of PLGA/HA NPs in aqueous solution was approximately 35.67-fold that of native HA (n-HA). PLGA/HA NPs had more superior stability compared with n-HA in physiological conditions. In this paper, a sample and sensitive LC-MS/MS method was validated for the first time to quantify HA in rat plasma. The pharmacokinetic parameters and bioavailability of HA between PLGA/HA NPs and n-HA were compared after oral administration in rat. The results implied that the relative bioavailability of PLGA/HA NPs was 2.67-fold that of n-HA, and PLGA/HA NPs had a longer half-life. Therefore, these results suggested that PLGA-blend nanoparticles improved the solubility, stability and bioavailability of HA, and could become a potential and promising carrier for the oral delivery of HA.
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APPLIED CATALYSIS B-ENVIRONMENTAL
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2017
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IF 9.446
Zheng Wan,Qian Xu,Hui Li,Yi Zhang,Yong Ding,Jide Wang
This paper introduces the first attempt of using well organized Co@CoO core-shell nanocrystals as an alternative toward noble metal catalysts for photocatalytic water splitting reactions. In this work, four kinds of stable magnetic Co@CoO core-shell nanocrystals were fabricated through a one-pot toluene-water two-phase interfacial reaction with oleic acid as a surfactant. The size and shape of the as-prepared crystals can be carefully adjusted through dynamically coating the closely packed monolayer of coordinating ligand onto the growing crystals. It is notable that spherical pine-nut-like hierarchical assemblies of Co@CoO core-shell nanoplates exhibit excellent photocatalytic activity (the maximum value of O 2 yield is over 96%). Even after the sixth run, the high catalytic activity of the recovered Co@CoO core-shell nanoplates remained.
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Frontiers of Chemical Science and Engineering
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2017
·Vol. 11
·期 4
·613-623
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IF 1.712
Tang Honggui,Li Shuangshuang,Gong Dandan,Guan Yi,Liu Yuan
Carbon deposition and sintering of active components such as nano particles are great challenges for Ni-based catalysts for CO methanation to generate synthetic natural gas from syngas. Facing the challenges, bimetallic catalysts with different Fe content derived from layered double hydroxide containing Ni, Fe, Mg, Al elements were prepared by co-precipitation method. Nanoparticles of Ni-Fe alloy were supported on mixed oxides of aluminium and magnesium after calcination and reduction. The catalysts were characterized by Brunner-Emmett-Teller (BET), X-ray diffraction, hydrogen temperature programmed reduction, inductively coupled plasma, X-ray photoelectron spectroscopy, transmission electron microscopy and thermogravimetric techniques, and their catalytic activity for CO methanation was investigated. The results show that the Ni-Fe alloy catalysts exhibit better catalytic performance than monometallic catalysts except for the Ni4Fe-red catalyst. The Ni2Fe-red catalyst shows the highest CO conversion (100% at 260–350 °C), as well as the highest CH 4 selectivity (over 95% at 280–350 °C), owing to the formation of Ni-Fe alloy. In stability test, the Ni2Fe-red catalyst exhibits great improvement in both anti-sintering and resistance to carbon formation compared with the Ni0Fe-red catalyst. The strong interaction between Ni and Fe element in alloy and surface distribution of Fe element not only inhibits the sintering of nanoparticles but restrains the formation of Ni clusters.
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RSC Advances
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2016
·Vol. 6
·期 100
·98147-98152
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IF 3.289
Yuting Cai,Gaolai Du,Guorong Gao,Jing Chen,Jun Fu
Monodisperse poly(NIPAM-co-AAc) microgels doped with either a monocolour photoluminescent quantum dot (QD) or multiple colour QDs have been fabricated by the charge-driven introduction of cysteamine-capped CdTe QDs and the collapse of the polymer network by adjusting the pH of the solution. The photoluminescence intensity and colour of the resulting microgels can be easily adjusted by changing the content of the CA–CdTe QDs in the hybrid microgels and using single or a mixture of different-sized QDs, respectively. In addition, the microgel-encapsulated QDs showed blue shifts, owing to surface coordination by the carboxylic acid. The combined effect of electrostatic interactions and surface chelating resulted in a reduction in microgel size. By tuning the ratio of QDs with different sizes, the photoluminescence of the hybrid hydrogels could be conveniently controlled. This work provides a facile and versatile method to fabricate colour-tunable or multifunctional hybrid hydrogels with broad potential applications.
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Metals
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2017
·Vol. 7
·期 4
·137
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IF 1.984
Xiaobo Wang,Taoyuan Ouyang,Xiaohua Duan,Chengzhu Ke,Xuemin Zhang,Jie Min,Aang Li,Weiyang Guo,Xudong Cheng
One type of multimodal (comprised of nanometer and sub-micrometer WC particles) and two types of conventional (comprised of nanometer and sub-micrometer WC particles, respectively) WC/Co powders were deposited on AISI 304L stainless steel substrates by using high velocity oxygen fuel spraying. The use of multimodal WC particles was indicated to have a beneficial effect on the solar absorptance (α) of the WC/Co coatings. The α of the multimodal WC coating reached 0.87, which was much higher than what can be achieved by either fine (0.82) or coarse powders (0.80) alone. By microstructural analysis, the enhancement in solar absorptance of the multimodal WC/Co coating was ascribed to the layer of distributed WC particles. During the thermal spraying, the nanostructured WC particles underwent rapid melting for the large specific surface area while the aggregated powders were heated, but not necessarily melted. The molten nano-WC would fill the available pores between the softened and heated aggregates, providing a layered distribution of WC particles for the spray-deposited coating. In this condition, the light-trapping in the multimodal coating will be enhanced due to the efficient light reflection among the multimodal WC particles, which contributes to the enhancement of solar absorptance.Keywords:solar selective absorbing coating;high velocity oxygen fuel;selective absorbing properties
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JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
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2016
·Vol. 28
·期 6
·4684-4689
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IF 1.798
Li Zheng,Zhang Le,Zhou Tianyuan,Wang Lixi,Wong Ching Ping,Yang Hao,Zhang Qitu
A novel spray co-precipitation method was adopted to synthesize well dispersed nanocrystalline Y 2 O 3 powders for transparent ceramics. Several analytic techniques such as XRD, SEM, BET and UV–Vis–NIR spectrophotometer were used to determine the properties of coprecipitated powders, and the microstructure and optical properties of as-fabricated ceramics. The influences of the aging time on powders and ceramics were systematically investigated. Precursors were completely reached to yield the Y 2 O 3 phase after being calcined at 1250 °C in air. The calcined Y 2 O 3 powders exhibited an approximately spherical morphology with narrow size distribution and weak agglomeration, with mean particle size of ~140 nm. The co-precipitated nanopowders with an aging time of 12 h exhibited the best sintering activity due to the low agglomeration, and the in-line transmittance of Y 2 O 3 ceramic sintered at 1800 °C for 8 h in vacuum reached to 77.2% at 1064 nm (1 mm thickness).
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JOURNAL OF ALLOYS AND COMPOUNDS
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2017
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IF 3.133
Huining Huang,Tao Wang,Haifeng Zhou,Dapeng Huang,Yaqiang Wu,Guangjun Zhou,Jifan Hu,Jie Zhan
Novel green-emitting Yb 3+ and Tb 3+ co-doped LaNbO 4 particles were prepared through a facile sol-gel and combustion method. X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), thermogravimetric and differential thermal analysis (TG-DTA), up-conversion luminescence (UCL) with different powers and varied concentrations, and luminescent lifetimes were employed to test the prepared samples. The XRD data exhibit that a sample with high crystallinity can be acquired at 1000 °C. FE-SEM images show homogeneous and spherical grains after Yb 3+ and Tb 3+ are co-doped in the LaNbO 4 samples. TG-DTA reveals that the LaNbO 4 synthetic process is accompanied by a temperature increase. In our work, we utilize a 980 nm laser to excite Yb 3+ ions to achieve the 2 F 7/2 → 2 F 5/2 transition, and the LaNbO 4 :Yb 3+ , Tb 3+ sample exhibits intense green emission. Luminescent spectra at different powers demonstrated the two-photon absorption process; meanwhile, the corresponding energy transfer mechanism from Yb 3+ to Tb 3+ and the emission of Tb 3+ under 980 nm laser excitation was described via an energy level diagram. Moreover, concentration-dependent up-conversion luminescent properties were systematically explored, and it was confirmed that LaNbO 4 :0.15Yb 3+ ,0.02Tb 3+ exhibits the strongest luminescent properties. In particular, as the content of Yb 3+ ions increases, the 5 D 4 → 7 F 6 transition quickly becomes stronger, resulting in the emitted color shifting from green to blue. Therefore, the emitted color can be tuned by adjusting the content of Yb 3+ ions. The excellent up-conversion emission properties of the obtained samples allow for their potential application in the fields of 3D display technologies and solid-state lasers.
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Catalysis Science & Technology
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2016
·Vol. 6
·期 19
·7273-7279
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IF 5.287
Guozhu Chen,Qihui Xu,Yong Wang,Guolong Song,Cuncheng Li,Wei Zhao,Weiliu Fan
It is still an important issue to develop a facile, environmentally friendly way to synthesize bimetal oxide materials. In this paper, Co3O4–CeO2 core–shell catalysts were prepared by an interfacial reaction, where Co(CO3)0.35Cl0.2(OH)1.1 nanorods were dispersed in Ce3+ aqueous solution for 2 days, followed by a calcination step. The samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). Based on the characterization and comparative experimental results, we proposed that the OH− ions slowly dissociated from the Co(CO3)0.35Cl0.2(OH)1.1 precursor combined with Ce3+ to develop into Ce(OH)3 nanoparticles because of its smaller solubility product constant than that of the Co precursor or Co(OH)2. Neither an additional precipitation agent nor stabilizing molecules were employed during the whole preparation. Raman spectroscopy and H2-temperature programmed reduction (H2-TPR) analysis revealed that there is a synergistic effect between Co3O4 and CeO2 in the as-prepared Co3O4–CeO2 core–shell catalysts, which is responsible for their enhanced catalytic activity toward CO oxidation in comparison to pure Co3O4 and CeO2.
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ELECTROCHEMISTRY COMMUNICATIONS
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2016
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IF 4.569
Zheng Xia,Wenze Qiu,Han Bao,Bin Yang,Lecheng Lei,Zhikang Xu,Zhongjian Li
A novel solid polymer electrolyte was developed by co-deposition of catechol (CCh) and polyethyleneimine (PEI) on a polypropylene membrane for electrochemical reduction of CO 2 (ERC) in gas phase. ERC performance was both investigated in a gas-gas mode and a gas-liquid mode. The maximum CO production rate was 121 μmol/h and the faradaic efficiency was 51% in the gas-liquid mode, which were much higher than those obtained with AM-7001 under the same condition. The high loading rate of quaternary ammonium ions on the membrane and the large surface area provided by the porous nano-structure of the membrane contribute to the high ERC efficiency. Furthermore, the cost of the CCh/PEI-Q membrane was much lower than commercial Nafion membranes, endowing this novel composite SPE with great potential in industrial application.
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JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY
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2016
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IF 4.179
Xiaohong Wang,Haiqian Hou,Yujun Li,Yingying Wang,Chen Hao,Cunwang Ge
A range of super-absorbent semi-IPN hydrogels—polyvinyl alcohol/poly (acrylic acid-co-acrylic amide) (PVA-P(AA-co-AM)) were synthesized via free radical polymerization method under ultrasound-assisted condition. L 16 (4 5 ) orthogonal experiments were designed to optimize the synthesis conditions and the success was characterized by FTIR, SEM and TGA. Swelling capacities were studied in various pH solution and saline solution whose results indicated that pH in solution shows an obvious influence on it and the salt resistance is greater in salt solution of low valence relative to that of high valence. Meanwhile, its swelling behavior was evaluated in water solution, which revealed that the swelling process conformed to the Schott model and the diffusion type was non-Fickian diffusion. Moreover, the adsorption on cobalt (II) from aqueous solutions was also investigated in the paper. The optimum pH value was found close to 4 for the cobalt (II) adsorption and it was discovered that adsorption kinetics and adsorption isotherms for cobalt (II) were in accordance with the pseudo-second-order model and the Freundlich model respectively. Besides, thermodynamic parameters were calculated for the cobalt (II) adsorption and the findings revealed that the adsorption behavior is spontaneous and endothermic.
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