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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高影响因子
JOURNAL OF THE ELECTROCHEMICAL SOCIETY
·
2018
·Vol. 165
·期 5
·A856
·
IF 3.662
Chenlong Wang,Xugang Zhang,Jinshuang Wang,Yongjun Ma,Shixian Lv,Junyu Xiang,Mingna Chu,Ting Sun,Chuanli Qin
From the practical application of supercapacitors, the development of carbon materials with high volumetric performance is highly desired. We report the synthesis of B/N/O co-doped carbon by a facile one-step carbonization method of polyvinylpyrrolidone/melamine formaldehyde resin with boric acid/urea treatment and a subsequent washing process. It is shown that a boric acid/urea treatment is an effective approach to incorporating B into N/O enriched carbon and effectively restraining the generation of inert B-O and B-N species. Moreover, a boric acid/urea treatment and washing process can increase specific surface area, optimize pore structure, and retain many active heteroatoms without lowering density, contributing to good conductivity, fast charge transfer and electrolyte ion diffusion, and high volumetric performance. The fabricated B/N/O co-doped carbon shows high active heteroatoms of 8.69 at.% (N-5, N-6, B-C and O-I), moderate surface area, and pore volume (778.02 m2 g−1 and 0.341 cm3 g−1), high density (1.3 g cm−3), high specific volumetric, and gravimetric capacitances (309 F cm−3 and 238 F g−1 at 0.5 A g−1) and superior cycling stability. The assembled symmetric supercapacitor delivers relatively high volumetric energy density (11.5 Wh L−1 at 622 W L−1) in 6 M KOH electrolyte. The B/N/O co-doped carbon has great potential for applications in supercapacitors.
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Journal of Materials Chemistry B
·
2018
·Vol. 6
·期 42
·6831-6841
·
IF 4.776
Lin Huang,Xin-Hua Liu,Xiao-Hong Zhang,Lei Tan,Chuan-Jun Liu
Bacterial infection is posing a great threat to human life, and constructing a platform to capture or kill the bacteria attached on a material surface is of particular significance. Herein, a nano-topographic material surface (SiNW-p-ppix@CDm) has been successfully synthesized based on silicon nanowire (SiNW) arrays modified with a random copolymer, which was decorated with photosensitive protoporphyrin IX (ppix) and β-CD-mannose7 (CDm). The as-prepared surface exhibits a highly efficient bacterial capture, which is based on the co-capture function between the SiNW topographic surface and the bacterial attachment molecule CDm, and sterilization of ppix under irradiation by 630 nm light. The Gram-negative bacterium Escherichia coli (E. coli) was adopted to evaluate the surface bactericidal efficiency. Finally, the killing efficiency can be proved to be 96.7% from fluorescence microscopy after staining with the live/dead bacterial viability kit. The reason for sterilization is that the bacterial cell wall had been split by the reactive oxygen species (ROS), which could be demonstrated via scanning electronic microscopy (SEM). This functional substrate could be used for bacterial enrichment apparatus such as used in water quality monitoring, and even in constructing clinical antibacterial materials.
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APPLIED CATALYSIS B-ENVIRONMENTAL
·
2018
·
IF 11.698
Zhishan Luo,Min Zhou,Xinchen Wang
In artificial photocatalysis, sluggish kinetics of hole transfer and the high recombination rate of charge have been the Achilles’ heel of photocatalytic conversion efficiency. The development of co-catalysts for promoting exciton splitting and charge separation has therefore gained continuous attention. Herein, “Co 4 O 4 ” cubane complex Co 4 O 4 (O 2 CMe) 4 (py) 4 ( 1a , py = pyridine derivatives), serves as a homogeneous molecular co-catalyst which is engineered into the framework of pristine polymeric carbon nitride (PCN) for water oxidation with light illumination. This modification strategy maximizes the contact areas between co-catalysts and reactants, reduces the over-potential of oxygen producing and accelerates the interface transfer rate of electron-hole pairs, thus leading to enhanced reaction kinetics for photocatalytic water oxidation. Compared with pristine PCN, the photocatalytic O 2 production rate up to 19-fold-enhanced in the presence of molecular co-catalyst. This work emphasizes the importance of developing effective, stable and earth-abundant molecular co-catalysts for the promotion of water-splitting photocatalysis.
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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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ChemCatChem
·
2018
·Vol. 10
·期 18
·4010-4017
·
IF 4.674
Kui Ma,Zhonghui Cui,Zhitao Zhang,Jingjing Huang,Zhirui Sun,Ye Tian,Tong Ding,Xingang Li
Graphical Blowing off steam : This paper describes a new approach of designing Cu−Ni bimetallic catalytic systems for dimethyl ether/methanol steam reforming. The Cu−Ni system exhibits an interesting alloy-mediated selectivity of CO and CH 4 , thereby producing hydrogen-rich reformates with an ultra-low CO concentration (<1000 ppm), which could be commercially potential for fuel cells. Steam reforming of simple oxygenated hydrocarbons without C−C bonds is suitable for small-scale decentralized H 2 production for fuel cells. However, the relatively high CO concentration in H 2 -rich reformates produced by traditional Cu-based catalysts will poison the Pt-based anode in fuel cells. Here, we describe a new approach to the design of Cu−Ni bimetallic catalysts based on nickel-phyllosilicate for steam reforming of dimethyl ether (DME). With the tunable formation of the Cu−Ni alloy, we can modulate the selectivity of CO and CH 4 in steam reforming and achieve H 2 -rich reformates with an ultra-low concentration of CO (below 1000 ppm). This process only requires simple and low-energy purification pretreatments to meet the requirements of commercial fuel cells. Mechanistic studies reveal that the Cu−Ni alloy can adsorb CO, particularly at high temperatures, and simultaneously suppress CO dissociation to methane.
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MATERIALS CHEMISTRY AND PHYSICS
·
2018
·
IF 2.21
Zhixiang Jiang,Yue Zhao,Ping Yang
Wire-in-tube and tube-in-tube structures have been prepared using single-spinneret electrospinning method through adjusting the preparation parameters of precursors and subsequent calcined process. Cobalt ferrite (CoFe 2 O 4 ) samples revealed wire-in-tube morphology using a Co/Fe molar ratio of 1/2. In the case of other a Co/Fe molar ratio, belt and porous fiber morphologies were created. Manganese ferrite (MnFe 2 O 4 ) sample exhibited tube-in-tube structure while nickel ferrite (NiFe 2 O 4 ) sample just exhibited tube structure. Because of no template in electrospun polymer composite nanofibers , the precursor diffusion process during calcination plays an important role for morphology controlling. The magnetic properties of samples were examined. The cobalt ferrite (CoFe 2 O 4 ) wire-in-tube sample revealed the highest saturation magnetization (60 emu/g). After growing with AlOOH on the surface, CoFe 2 O 4 wire-in-tube sample revealed a high efficiency for the removal of Congo red pollutant. These nanostructures are particularly attractive for use in the field of nano-fluidic and nano-energy harvesting devices.
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LIFE SCIENCES
·
2018
·
IF 3.234
Yijie Zhou,Dan Du,Shuyun Liu,Meng Zhao,Yujia Yuan,Lan Li,Younan Chen,Yanrong Lu,Jingqiu Cheng,Jingping Liu
Aims Ischemic acute kidney injury (AKI) is a serious clinical problem and no efficient therapeutics is available in clinic now. Natural polyacetylene glycosides (PGAs) had shown antioxidant and anti-inflammatory properties, but their effects on kidney injury have not been evaluated. This study aimed to investigate the protective effect of PGA on ischemic kidney injury in renal tubular epithelial cells (TECs) and mice. Main methods Hypoxic HK-2 cells and renal ischemia/reperfusion injury (IRI) mice were treated with PGA from Coreopsis tinctoria , and the cell viability, renal function, apoptosis, inflammation, mitochondrial injury, lipids metabolism were analyzed. Key findings In vitro results showed that PGA improved cell viability and reduced oxidative stress, pro-apoptotic/pro-inflammatory factors expression and NFκB activation in TECs under hypoxia/reperfusion (H/R). Moreover, PGA reduced mitochondria oxidative stress and improved ATP production, ΔΨm and mitochondria biogenesis, and inhibited lipids uptake, biosynthesis and accumulation in hypoxic TECs. In vivo, PGA significantly attenuated kidney injury and reduced blood urea nitrogen (BUN), serum creatinine (CREA) and urinary albumin (Alb), and increased creatinine clearance (CC) in IRI mice. PGA also decreased cell apoptosis, mitochondria oxidative stress, inflammatory response and lipid droplets accumulation, and promoted ATP generation in kidney of IRI mice. Significance Our results proved that PGA ameliorated ischemic kidney injury via synergic anti-inflammation, mitochondria protection and anti-lipotoxicity actions, and it might be a promising multi-target therapy for ischemic AKI.
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RSC Advances
·
2018
·Vol. 8
·期 3
·1378-1384
·
IF 2.936
Zhenzhen Wei,Zhijuan Pan,Faxue Li,Jianyong Yu
Tailoring the wetting properties of nanofibrous membranes and endowing them with expected wettability provides new ways in extending the application field of these materials. In this study, we first performed the in situ fabrication of poly(butylenes succinate-co-terephthalate) (PBST) composite nanofibrous membrane with cyclodextrin polymer (CDP) using a combination of electrospinning and heating processes. Then, the morphologies, crystallization and mechanical properties of the PBST composite membrane were investigated. It was found that the CDP was uniformly dispersed on the PBST nanofibers instead of merely covering the surface of the membrane. Moreover, the introduction of additives brought about a decreased crystallinity and tensile strength of the resultant membrane due to its restraining role in the crystallization of PBST. Furthermore, the wettability of the PBST composite membranes with various amounts of additives was explored and the evolution of water spread on top of the membranes was also recorded. The membrane became superhydrophilic from hydrophobic upon increasing the amount of additives and the water droplet could completely spread within 0.2 s, which was attributed to the enlarged roughness and increased contact area of CDP on the nanofibers. A comparison between the two fabrication methods used for PBST composite nanofibrous membranes is also presented and studies on the preparation and wetting properties may shed light on polymer composite membranes that exhibit potential application in more fields.
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JOURNAL OF PHYSICS D-APPLIED PHYSICS
·
2018
·Vol. 51
·期 21
·215305
·
IF 2.373
Panpan Zhang,Jiupeng Zhao,Ke Zhang,Yiyong Wu,Yao Li
A series of porous polyimide (PI) membranes with 3,3',4,4'-benzophenonetetracarboxylic dianhydride (BTDA) and 4,4'-diaminodiphenyl ether (ODA) in the different ratio of co-solvent (N, N-dimethylacetamide (DMAC)/1, 4-butyrolactone (GBL)) were prepared by a novel wet phase inversion method. The influence of co-solvent on the structure and dielectric properties of membranes were investigated. PI membranes changed from finger-like structure to spongy-like structure with the increasing of the GBL content since the intermolecular interaction between PI induced by GBL. The proportion and size of finger-like structure gradually decreased with the increase of GBL content in DMAC/GBL co-solvent. Although PI membranes exhibited low dielectric permittivity ranges from 1.7–2.5, the dielectric breakdown strengths were also relatively low. In particular, the PI from pure GBL yielded the highest breakdown strength (260.05 kV mm−1) since the low proportion of macrovoids and defects. Moreover, when the ratio of GBL/DAMC was 84/16, the resultant PI membrane possessed a low dielectric constant (1.99) as well as relatively high breakdown strength (100.53 kV mm−1). Therefore, porous PI membraness may be potential in many applications of electronics and microelectronics.
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Polymers
·
2018
·Vol. 10
·期 9
·934
·
IF 2.935
Guangqian Zhu,Xianhui Zhang,Mengmeng Zhao,Liang Wang,Chuyang Jing,Peng Wang,Xiaowu Wang,Qinggang Wang
A series of iminopyridine complexes of Fe(II) and Co(II) complexes bearing fluorinated aryl substituents were synthesized for the polymerization of isoprene. The structures of complexes3a,2band3bwere determined by X-ray diffraction analysis. Complex3acontained two iminopyridine ligands coordinated to the iron metal center forming an octahedral geometry, whereas2badopted a chloro-bridged dimer, and3bfeatured with two patterns of cobalt centers bridged via chlorine atoms. Complexes2band3brepresented rare examples of chlorine bridged bimetallic Co(II) complexes. The fluorine substituents effects, particularly on catalytic activity and polymer properties such as molecular weight and regio-/stereo-selectivity were investigated when these complexes were employed for isoprene polymerization. Among the Fe(II)/methylaluminoxane (MAO) systems, the 4-CF3substituted iminopyridine Fe(II) complex1awas found as a highly active isoprene polymerization catalyst exhibiting the highest activity of 106g·(mol of Fe)−1·h−1. The resultant polymer displayed lower molecular weight (Mn= 3.5 × 104g/mol) and moderate polydispersity index (PDI = 2.1). Furthermore, the ratio ofcis-1,4-/3,4 was not affected by the F substituents. In the series of Co(II)/AlEt2Cl binary systems, complexes containing electron-withdrawing N-aryl substituents (R = 4-CF3, 2,6-2F) afforded higher molecular weights polyisoprene than that was obtained by the complex containing electron-donating N-alkyl substituents (R = octyl). However, ternary components system, complex/MAO/[Ph3C][B(C6F5)4] resulted in low molecular weight polyisoprene (Mn< 2000) with hightrans-1,4-unit (>95%).Keywords:iminopyridine ligands;Fe(II);Co(II) complexes;isoprene polymerization;fluorinated aryl substituents
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MICROPOROUS AND MESOPOROUS MATERIALS
·
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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