APPLIED SURFACE SCIENCE
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2019
·
IF 5.155
Jinhe Shu,Qijian Niu,Nannan Wang,Jun Nie,Guiping Ma
Exploring biomass-derived non-precious metal carbon-based electrocatalysts have attracted intensive interest in the field of energy conversion due to their low-cost, ecofriendly and sustainable. Herein, we report a novel strategy for preparation of Co/N doped hierarchical porous carbon microspheres (Co/NHPCMS), via pyrolysis ZIF-67@SA/NaHCO 3 microspheres prepared by in-situ growth of ZIF-67 on electrospray Co-SA/NaHCO 3 microspheres. ZIF-67 nanocrystals were well distributed on the ions cross-linked alginate/NaHCO 3 microspheres. The pyrolysis of ZIF-67@SA/NaHCO 3 microspheres could provide abundant active sites and rich porous structure. More importantly, NaHCO 3 plays an essential role in obtaining large mesopores and high pore volume , which is benefit to facilitate the diffusion of reactants. With these merits, Co/NHPCMS-600 exhibits an outstanding ORR electrocatalytic performance with a half-wave potential of 0.827 V. Besides, Co/NHPCMS-600 catalyst exhibits superior catalytic stability and tolerance to methanol in the ORR. This work provides a promising route based on sustainable biomass toward high performance electrocatalyst in the field of energy conversion.
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LANGMUIR
·
2019
·
IF 3.683
Binbin Wan,Junying Li,Feng Ma,Ning Yu,Wenjing Zhang,Lujie Jiang,Hengshan Wei
The immobilized metal affinity cryogels based on poly(2-hydroxyethyl methacrylate-co-glycidyl methacrylate) (p(HEMA-GMA)) containing hydroxy and epoxy groups were prepared by free-radical copolymerization under cryogenic condition and then functionalized with iminodiacetic acid and chelated Cu2+, Ca2+, and Fe3+ ions to the p(HEMA-GMA) cryogel. The structures of p(HEMA-GMA) and immobilized metal-affinity cryogels were analyzed by Fourier transform infrared spectroscopy and scanning electron microscopy (SEM)–energy dispersive X-ray spectroscopy. SEM results showed that the prepared cryogels had interconnected pores with the size of 30–100 μm. The performance of water swelling into the cryogels was fitted in Fickian diffusion. The adsorption property of cryogels was influenced by the immobilized ionic type, temperature, and adsorbate. The adsorption capacity of immobilized Cu2+ cryogel (p(HEMA)–Cu2+ (0.5 M) cryogel) was the highest in comparison with that of Ca2+ and Fe3+ affinity cryogels under the same condition. The maximum adsorption capacity of p(HEMA)–Cu2+ (0.5 M) cryogel for porcine pancreatic lipase was 150.14 mg/g at a higher temperature of 35 °C, whereas for bovine serum albumin, the maximum adsorption capacity was 154.11 mg/g at a lower temperature of 25 °C. The research of thermodynamics and kinetics indicated that the mechanism of the protein adsorption process corresponded to the Langmuir model and pseudo-second-order model.
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JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY
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2019
·Vol. 19
·期 8
·4414-4428
·
IF 1.093
Liu Debao,Yang Ping
Metal-organic framework (MOF) has received much attention to prepare metal oxides, demonstrating many applications in sensing, catalysis and energy storage and conversion. Herein, a two-step procedure by a metal organic frameworks route was used fabricate ZnO dodecahedra, Co3O4
dodecahedra, ZnO/Co3O4 and Co3O4/NiO composites. The growth mechanisms for these unique structures are illustrated. As applications, ZnO dodecahedra perform remarkable sensitivity to ethanol in sensing experiments. The CO catalytic oxidation activity
of Co3O4 dodecahedra is employed and showed decreased catalytic performance with the increased calcinations temperature. ZnO/Co3O4 composites show enhanced electrochemical performance and photocatalytic activities, which result from its unique porous
structure, high specific surface area and the synergistic effect between ZnO and Co3O4. In addition, Co3O4/NiO composites show remarkable specific capacitance and excellent stability, superior to that of the pure Co3O4. Moreover,
this MOF-driven method could be utilizable to prepare other metal oxide for various applications.
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SCRIPTA MATERIALIA
·
2019
·
IF 4.539
Qiang Liu,Penghui Chen,Nan Jiang,Xing Zhang,Xiaoying Li,Sha Su,Zewang Hu,Haohong Chen,Tengfei Xie,Jiang Li
8.7 mol% Y 2 O 3 -ZrO 2 (Y 0.16 Zr 0.84 O 1.92 ) precursor was synthesized by the co-precipitation method using ammonia as the precipitant. The Y 0.16 Zr 0.84 O 1.92 powders calcined at 800 °C show a pure c-ZrO 2 phase. The average crystallite size of the powders is 12.4 nm and weakly agglomerated to an average particle size of 15.5 nm. Y 0.16 Zr 0.84 O 1.92 transparent ceramics were then successfully fabricated by pre-sintering at 1350 °C for 2 h and HIP post-treatment at 1750 °C for 1 h under 200 MPa without sintering additives. The in-line transmittance of Y 0.16 Zr 0.84 O 1.92 ceramics (1 mm thick) exceeds 50.3% in the region of 400–850 nm, reaching about 65.3% at 800 nm.
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ACS Applied Materials & Interfaces
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2019
·
IF 8.456
Fucheng Wang,Jiajun Li,Chunsheng Shi,Enzuo Liu,Chunnian He,Naiqin Zhao
Ceramic phase reinforced aluminum matrix composites (CAMCs) are widely used in high-tech fields represented by aerospace industry due to their advantages of high specific strength, high specific modulus, high thermal stability, and light weight. Strong interface bonding is a prerequisite for high performance of multiphase materials. Herein, a novel CAMC in situ reinforced by MgAl2O4 particles and MgAlB4 nanorods was prepared by vacuum hot-pressing combined with hot-extrusion process. A high-resolution transmission electron microscope was used to characterize the orientation relationship and interface structure between the ceramic phases and the aluminum matrix. Two orientation relationships (OR1 and OR2) of MgAl2O4/Al and one (OR3) of MgAlB4/Al are determined: OR1-[011]p//[011]Al, (11̅1)p//(11̅1)Al; OR2-[211]p//[011]Al, (113̅)p//(022̅)Al; OR3-[101̅0]R//[001]Al, (0002)R//(2̅20)Al. The MgAl2O4 in OR1 forms a coherent interface with the aluminum matrix at (111) surface, while they form a 4 × 5 near coincidence site lattice (CSL) interface structure for OR2. In OR3, the MgAlB4 forms an approximate coherent interface with Al matrix at its (0002) surface and a 2 × 5 CSL interface structure at its (011̅0) surface. First-principles calculations suggest that MgAl2O4 combines to aluminum at (111) plane through covalent bonds, which means high interfacial bonding strength. The hot-extrusion process makes the ceramic phase evenly distributed in the matrix. The mechanical properties of the composites are greatly improved compared with pure aluminum.
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CHEMICAL ENGINEERING JOURNAL
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2019
·
IF 8.355
Jing Qiao,Xue Zhang,Dongmei Xu,Lingxin Kong,Longfei Lv,Fan Yang,Fenglong Wang,Wei Liu,Jiurong Liu
Carbon materials are widely used for electromagnetic wave absorption. However, to find out a more rational approach to improve the electromagnetic (EM) wave absorption performance is still worthy of attention. In this work, the carbon nanofibers (CNFs) decorated by titanium oxide and metallic cobalt (TiO 2 /Co/CNFs) were synthesized by electrospinning and carbonizing process, and the microtopography, structure, composition and magnetic properties of which were characterized in detail. The TiO 2 /Co/CNFs nanocomposites acquired optimal electromagnetism parameters and exhibited superb electromagnetic wave absorption property. The results showed that the minimum reflection loss (RL) values of TiO 2 /Co/CNFs samples with different filling ratios are less than −50 dB with the matching thickness less than 3.5 mm. The maximum effective absorption bandwidths (RL ≤ −10 dB) exceed 5.2 GHz. Besides, the strong absorption frequency range can be regulated by adjusting filling ratios to broaden the application. This work provides a unique approach to design carbon nanofibers loaded with oxides or metals, and the TiO 2 /Co/CNFs nanocomposites could be an ideal candidate as light-weight and high-efficiency electromagnetic wave absorption materials and the tunable absorption property portend the potential application in various environmental conditions.
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JOURNAL OF ALLOYS AND COMPOUNDS
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2018
·
IF 3.779
Lijing Wang,Gan Jin,Yanhong Shi,Hao Zhang,Haiming Xie,Bai Yang,Haizhu Sun
Two-dimensional (2D) ZnS-SnS 2 porous nanosheets are designed as clean and low cost photocatalysts for water splitting. The composites successfully combine high photoelectron reduction potential of ZnS with the sufficient sunlight harvesting ability of SnS 2 . Moreover, SnS 2 acts as an effective electron transfer medium from ZnS to SnS 2 due to the construction of quasi-type II structure. This greatly promotes the transfer of electron-hole pairs and effectively inhibits their recombination. Especially, the unique porous nanosheets structure maintains them high specific surface area and countless reactive sites, which increases the reactants' contact area and facilitates the migration of carriers upon photocatalysis . This further suppresses the charge recombination and improves the photocatalysts' stability. As a result, an optimized specific surface area of 246.7 m 2 g −1 and photocatalytic H 2 generation rate of 536 μmol h −1 g −1 are achieved in the absence of a surfactant and co-catalyst, which is 10 times higher than ZnS and 17 times higher than SnS 2 . In addition, the porous nanosheets have fairly good photocatalytic stability and can be reused at least five cycles without obvious changes in activity and structure. This work successfully presents the potential of ZnS and SnS 2 -based photocatalyst for clean and low cost hydrogen production from water splitting.
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JOURNAL OF CRYSTAL GROWTH
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2019
·
IF 1.573
Junli Wang,Yajie Qiao,Tingting Wang,Kangmin Chen
In this work, we combine the catalytic growth and ligand control mechanisms to synthesize ultrathin/ultralong ZnSe nanowires (NWs). Ag 2 Se catalyst seeds initiate the NW growth and significantly cause the increase of the NW lengths up to several micrometers. The long-chain amine mixture of oleylamine and 1-dodecylamine acts as reaction medium and ligands (or surfactants) to control the sizes of Ag 2 Se seeds and ZnSe NWs within several nanometers (the mean diameter of NWs: ∼5.5 nm). The microstructure studies by HRTEM reveal the presence of zinc blende (ZB)/wurtzite (W) alternations and a number of stacking faults and twins within individual ZnSe ultrathin NWs. These NWs exhibit optical quantum confinement effect due to the diameters smaller than the theoretical exciton Bohr diameter of bulk ZnSe. Raman spectrum and photoelectronic performance under white light illumination are also presented.
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MICROPOROUS AND MESOPOROUS MATERIALS
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2018
·
IF 3.649
Yongteng Qian,Jimin Du,Dae Joon Kang
Highly porous nanostructures having large specific surface areas are very desirable for electrochemical supercapacitors to achieve a large energy storage capacity. We synthesized porous Co-doped TiO 2 nanostructures with an average diameter of 450 nm through a simple solvothermal method by using tetrabutyl titanate and cobalt acetate as precursors and polystyrene beads as templates. The optimized 7% Co-doped TiO 2 nanostructures-based supercapacitor electrodes exhibited a specific capacitance of 352 F g -1 at a current density of 0.5 A g −1 while retaining a capacity of 97.2% after 3000 cycles. This excellent electrochemical performance may be ascribed to the synergistic effects originating from conductivity enhancement of TiO 2 through optimized Co-doping and larger specific surface areas rendered by structural porosity, when compared to the undoped TiO 2 samples. Our results suggest that porous Co-doped TiO 2 nanostructures can be explored for potential electrochemical applications.
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CERAMICS INTERNATIONAL
·
2018
·
IF 3.057
Chao Xia,Caiyan Yu,Mengmeng Cao,Jinfeng Xia,Danyu Jiang,Guohong Zhou,Dafeng Zhang,Huili Li
In this work, a new Eu and Tb co-doped luminescent compound based on MOF-5, [Zn 4 O(BDC) 3 ], (named as compound 1 ) was successfully synthesized. The structure and morphology characterizations demonstrate that the initial framework of MOF-5 is retained well after co-doping Eu and Tb. The systematic investigations of photoluminescence behaviors reveal that the heat-treated compound 1 (called as compound 1a ) can be utilized as a multi-channel readout luminescent thermometer in emission intensity ratio, decay time ratio, and luminescence color. It simultaneously exhibits the excellent repetitiveness and reversibility under high temperature region from 303 to 473 K. The relative sensitivity of 1.8%/K at 473 K is much higher than the best one of 1.19%/K previously reported for the mixed-lanthanide MOF Tb 0.8 Eu 0.2 BPDA. Until now, such a ratiometric luminescent thermometer with a high sensitivity at the temperature as high as 473 K has been rarely explored.
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LANGMUIR
·
2018
·
IF 3.789
Yan Lv,Shang-Jin Yang,Yong Du,Hao-Cheng Yang,Zhi-Kang Xu
Polydopamine-based chemistry has been employed for various surface modifications attributed to the advantages of universality, versatility, and simplicity. Co-deposition of polydopamine (PDA) with polyethyleneimine (PEI) has then been proposed to realize one-step fabrication of functional coatings with improved morphology uniformity, surface hydrophilicity, and chemical stability. Herein, we report the co-deposition kinetics related to the solution composition with different dopamine/PEI ratios, PEI molecular weights, dopamine/PEI concentrations, and the substrate surface with varying chemistry and wettability. The addition of PEI to dopamine solution suppresses the precipitation of PDA aggregates, resulting in an expanded time window of steady co-deposition compared with that of PDA deposition. Low-molecular-weight PEI at low concentration accelerates the co-deposition process, while high-molecular-weight PEI and high concentration of either PEI or dopamine/PEI are detrimental to the co-deposition efficiency. Meanwhile, the surface morphology and chemical composition of the co-deposition coatings can be regulated by the solution conditions during co-deposition. Moreover, obvious deviations in the co-deposition rate and the amount of substrates bearing various functional groups, such as alkyl, phenyl, hydroxyl, and carboxyl, are revealed, which are quite different from PDA deposition. The initial adsorption rates further reflect the change in interactions between the aggregates and these substrates caused by PEI, which follows the sequence of carboxyl > hydroxyl > alkyl > phenyl. These results provide deep insights into the PDA/PEI co-deposition process on various substrates.
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ZEITSCHRIFT FUR PHYSIKALISCHE CHEMIE-INTERNATIONAL JOURNAL OF RESEARCH IN PHYSICAL CHEMISTRY & CHEMICAL PHYSICS
·
2018
·Vol. 233
·期 3
·347-359
·
IF 1.144
Zuming He,Yongmei Xia,Bin Tang,Jiangbin Su,Xingfang Jiang
A series of magnetically recyclable NiFe 2 O 4 /ZnO nanocomposites have been successfully fabricated by a facile two-step route. The as-prepared NiFe 2 O 4 /ZnO nanocomposites were characterized by X-ray diffraction, field-emission scanning electron microscopy, vibrating sample magnetometer, ultraviolet-visible diffuse reflectance spectroscopy and photoluminescence spectroscopy. The results demonstrate that the NiFe 2 O 4 /ZnO nanocomposites are composed of ZnO particles (50–120 nm) integrated with NiFe 2 O 4 particles (30–80 nm) . Compared with bare ZnO, the NiFe 2 O 4 /ZnO nanocomposites exhibit evidently enhanced visible light absorption and decreased recombination of photo-generated electron-hole pairs. Moreover, the nanocomposites exhibit enhanced photocatalytic performance for the degradation of methylene blue under simulated solar light irradiation when compared with bare ZnO, and the 20%-NiFe 2 O 4 /ZnO nanocomposite is observed as the optimal composite. This is ascribed to the more efficient separation of photo-generated electron-hole pairs and generation of hydroxyl (˙OH) radicals in the 20%-NiFe 2 O 4 /ZnO nanocomposite. Furthermore, the NiFe 2 O 4 /ZnO nanocomposites have a high saturation magnetization, indicating that they can be magnetically separated and recycled from organic dye wastewater.
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