ACS Applied Energy Materials
·
2018
·
IF 0
Xiaorong Gan,Lawrence Yoon Suk Lee,Kwok-yin Wong,Tsz Wing Lo,Kwun Hei Ho,Dang Yuan Lei,Huimin Zhao
The phase transition of multilayer MoS2 nanosheets from semiconducting 2H to metallic 1T (2H/1T) has been realized mainly by chemical methods (e.g., Li intercalation). Here, we develop a simple yet effective method, cyclic voltammetry, to successfully tune the 2H/1T phase transition of multilayer MoS2 nanosheets without using intercalation species. The phase transition is triggered by the electrochemical incorporation of S vacancies (obtained by electrochemical etching), which on the one hand injects electrons into the framework of S–Mo–S and on the other hand facilitates the sliding of S planes. Density functional theory calculations show that O doping in the framework of S–Mo–S decreases the energy barrier for forming S vacancies and stabilizes the 1T-phase by occupying the 4d orbital of Mo. Our calculations further show that the presence of S vacancies and O incorporation not only reduces the bandgap of MoS2, indicating an increased conductivity, but also decreases the hydrogen adsorption free energy, implying significant improvement of hydrogen evolution reaction (HER) activity. Indeed, the overpotential and Tafel plot of the electrochemically treated MoS2 nanosheets are decreased respectively by 174 mV and 25 mV/dec at a cathodic current density of 10 mA cm–2 compared with pristine 2H-MoS2 nanosheets. The HER experiment also reveals the order of catalytical activity for the studied phases and structural defects: 1T-MoS2 > S vacancies > O doping >2H-MoS2. Our study has provided a new route to control the phase transition of multilayer MoS2 nanosheets with promising applications potentially in catalysis and optoelectronics.
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Materials
·
2018
·Vol. 11
·期 9
·1720
·
IF 2.467
Qiuyan Hao,Guoliang Cui,Yuan Tian,Taizhe Tan,Yongguang Zhang
In this paper, the synthesis of the three-dimensional (3D) composite of spherical reduced graphene oxide (RGO) with uniformly distributed CeO2particles is reported. This synthesis is done via a facile and large-scalable spray-drying process, and the CeO2/RGO materials are hydrothermally compounded with sulfur. The morphology, composition, structure, and electrochemical properties of the 3D S/CeO2/RGO composite are studied using X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), thermal gravimetric analysis (TGA), Raman spectra and X-ray photoelectron spectroscopy (XPS), etc. The electrochemical performance of the composites as electrodes for lithium–sulfur batteries is evaluated. The S/CeO2/RGO composites deliver a high initial capacity of 1054 mAh g−1, and retain a reversible capacity of 792 mAh g−1after 200 cycles at 0.1 C. Profiting from the combined effect of CeO2and RGO, the CeO2/RGO materials effectively inhibit the dissolution of polysulfides, and the coating of spherical RGO improves the structural stability as well as conductivity.Keywords:Lithium–sulfur battery;CeO2/RGO composite;electrochemical performance
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高影响因子
JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
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2014
·
IF 3.107
Yan-Qing Wang,Hong-Mei Zhang
The effects of bisphenol S on the structures and activities of trypsin and pepsin were investigated by various methods like UV–visible absorbance, fluorescence, circular dichroism, and molecular docking. The secondary and tertiary structures of trypsin and pepsin were altered by bisphenol S binding, which resulted in the loosening of the skeletons of trypsin and pepsin. In addition, bisphenol S induced microenvironmental changes around tyrosine and tryptophan residues of trypsin and pepsin. The activity experimental results showed that the activity of pepsin decreases obviously with the increasing concentration of BPS, while the activity of trypsin does not change remarkably. The binding and thermodynamic parameters obtained by molecular docking and fluorescence spectroscopy showed that the bindings of bisphenol S to trypsin and pepsin were spontaneous processes and hydrogen bonding and hydrophobic interactions played a vital role in stabilizing the bisphenol S–trypsin and bisphenol S–pepsin complexes. The binding constants (KA) of bisphenol S with trypsin were 7.42 × 104 (298 K) and 5.91 × 104 L/mol (310 K), and those of pepsin were 5.78 × 104 (298 K) and 4.44 × 104 L/mol (310 K). Moreover, there was one main kind of binding site for bisphenol S on trypsin or pepsin.
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高影响因子
JOURNAL OF POLYMER RESEARCH
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2014
·Vol. 21
·期 11
·1-8
·
IF 1.897
Ran Xiaoqi,Yi Shixiong,Liang Liefeng,Yang Xiao
The effect of oxygen on photodegradation of π-conjugated aromatic poly(1,3,4-oxadiazole)s (POD) was studied in detail. The results obtained by tensile test, UV-spectra and ATR-FTIR revealed that the oxygen was indispensable during photodegradation of POD. The occurrence of photodegradation of POD must be combination of UV exposure and oxygen simultaneously. The state of oxygen during photodegradation of POD was investigated by nitrotetrazolium blue chloride (NBT) method. The result illustrated that the oxygen was transformed into superoxide anion radical through accepting one electron during UV exposure. Results of tensile tests and UV-spectra further proved that the superoxide anion radical could combine with excited POD to form an unstable product that lead to occurrence of photodegradation. Singlet oxygen was also investigated and the result showed that POD appeared to be stable to singlet oxygen.
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高影响因子
Materials Research Express
·
2014
·Vol. 1
·期 1
·015033
·
IF 0
Yanyan Chen,Shenjie Li,Lijian Huang,Daocheng Pan
Au+ ions have been successfully incorporated into the lattice of ZnxCd1−xS quantum dots as luminescent centers via an aqueous method. The dopant emission can be tuned in the range of 445 to 570 nm, and the highest quantum yield can reach as high as 30%. Our results showed that Au+ ions can be used as an excellent luminescent dopant in doped quantum dots. Finally, these water-soluble quantum dots can be used directly in PL imaging of HepG2 cells without conjugating any biological targets, indicating a high potential application in bio-labeling.
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PROCESS BIOCHEMISTRY
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2013
·
IF 2.414
Yuxiang Tang,Wei Liu,Jiangling Wan,Yuanxin Wang,Xiangliang Yang
We report the selective recovery of S-adenosylmethionine (SAM) from fermentation broths using a two-stage supported liquid membrane system with strip dispersion (SLM-SD). The system utilized two MiniModule ® hollow-fiber membrane modules as microporous supports and an organic membrane solution consisting of the extractants of sodium di-2-ethylhexyl sulfosuccinate (AOT), di-(2-ethylhexyl)phosphoric acid (DEHPA), and trioctylphosphine oxide (TOPO) in the solvent n-octanol. SAM was extracted in the first membrane module. Methionine (Met) was captured by the first stripping solution and further purified in the second membrane module. pH values in the feed phase and the first and second stripping solutions, extractant concentrations, NaCl concentration, and the SAM acceptor in the first stripping solution were optimized. Strip dispersion mixing speed, pressure differences across the membranes, and flow rates of the feed and strip dispersion phases were investigated experimentally. The optimal extractant concentrations were: AOT 2.78 wt%, DEHPA 27.0 wt%, and TOPO 1.61 wt%. The optimal pH values in the feed phase and the first and second stripping solution were 3.0, 2.5, and 1.0, respectively. SAM extraction efficiency of 98.7%, SAM recovery efficiency of 91.8% and Met removal efficiency of 85.4% were achieved within 5 h. Finally, the mass transfer analysis indicated that the mass transfer resistances from the extraction reaction and the membrane phase were predominant.
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高影响因子
APPLIED SURFACE SCIENCE
·
2014
·
IF 2.538
Yanlin Zhang,Peihong Liu,Honghai Wu
One-dimensional (1D) nanowire material (especially nonmetal doped 1D nanowires) synthesized by a facile way is of great significance and greatly desired as it has higher charge carrier mobility and lower carrier recombination rate. N, S-codoped TiO 2 nanowires were synthesized using titanium sulfate as a precursor and isopropanol as a protective capping agent by a hydrothermal route. The obtained doped nanowires were characterized by XRD, SEM, HRTEM, SAED, XPS, BET and UV–vis absorption spectrum. The incorporation of N and S into TiO 2 NWs can lead to the expansion of its lattice and remarkably lower its electron-transfer resistance. Photocatalytic activity measurement showed that the N, S-codoped TiO 2 nanowires with high quantum efficiency revealed the best photocatalytic performance for atrazine degradation under visible light irradiation compared to N, S-codoped TiO 2 nanoparticles and S-doped TiO 2 nanowires, which was attributed to (i) the synergistic effect of N and S doping in narrowing the band gap, separating electron–hole pairs and increasing the photoinduced electrons, and (ii) extending the anatase-to-rutile transformation temperature above 600 °C.
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高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2014
·
IF 2.235
Qiheng Tang,Rongjie Yang,Yun Song,Jiyu He
A series of flame-retarded thermoplastic poly(imide–urethane)s (TPIUs) with either ammonium polyphosphate (APP) alone or APP and dipentaerythritol (DPER) have been prepared. The fracture strength and strain of TPIU composites decrease with increasing amount of intumescent flame retardant (IFR), as shown by tensile tests. Thermogravimetric analysis shows that the initial decomposition temperature (T5%) of TPIU composites decreases with increasing IFR loading. The flame retardancies of these TPIU composites have also been tested according to the limiting oxygen index (LOI) and UL-94 standards. The results have indicated that the LOI value of TPIU/APP is a little higher than that of TPIU/(APP + DPER) with the same loading. Furthermore, 50% APP alone or APP + DPER incorporation into TPIU allowed attainment of the UL-94 V-0 standard. Details of fire behavior, such as time to ignition, heat release rate, peak of the heat release rate, total smoke release, and total heat release, have been tested by means of a cone calorimeter. Moreover, the char residues of TPIU composites after cone calorimetry have been investigated in detail by scanning electron microscopy, Fourier transform infrared, and energy-dispersive X-ray reflectometry.
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高影响因子
JOURNAL OF SURFACTANTS AND DETERGENTS
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2017
·Vol. 20
·期 6
·1255-1262
·
IF 1.45
Niu Ruixia,Wang Chao,Sun Zhigang,Long Biao,Song Hua,Ren Weidong,Wang Daqiang,He Junyao
A series of alkyl sulphobetaine Gemini surfactants C
n
-GSBS ( n = 8, 10, 12, 14, 16) was synthesized, using aliphatic amine, cyanuric chloride, ethylenediamine, N , N ′-dimethyl-1,3-propyldiamine and sodium 2-chloroethane sulfonate as main raw materials. The chemical structures were confirmed by FT-IR, 1 H NMR and elemental analysis. The Krafft points differ markedly with different carbon chain length, for C 8 -GSBS, C 10 -GSBS and C 12 -GSBS are considered to be below 0 °C and C 14 -GSBS, C 16 -GSBS are higher than 0 °C but lower than room temperature. Surface-active properties were studied by surface tension and electrical conductivity. Critical micelle concentrations were much lower than dodecyl sulphobetaine (BS-12) and decreased with increasing length of the carbon chain from 8 to 16, and can reach a minimum as low as 5 × 10 −5 mol L −1 for C 16 -GSBS. Effects of carbon chain length and concentration of C
n
-GSBS on crude oil emulsion stability were also investigated and discussed.
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高影响因子
JOURNAL OF POLYMER RESEARCH
·
2017
·Vol. 24
·期 10
·1-10
·
IF 1.615
Lu Jiehong,Yan Guangming,Zhang Gang,Yang Jie
A series of poly(arylene ether)s with pendant cyclohexyl units had been prepared by solution polycondensation of 4,4′-cyclohexane-1,1′-diyldiphenol (CHDP) and 4,4′-difluorobenzophenone (DFBP) (or 4,4′-difluorodiphenylsulfone (DFDPS)). The inherent viscosities of obtained poly(arylene ether)s were in the range of 0.49–0.97 dLg −1 . They were found to have high glass transition temperatures (T g ) of 158–208 °C, and good thermal stability with 5% weight-loss temperature (T 5% ) of 442–484 °C. The tensile test and dynamic mechanical analysis results indicate the good mechanical properties of poly(arylene ether)s. Their Young’s Mdoulus were found to be 2.2–2.3 GPa, tensile strengths were 81.0–97.7 MPa, storage mdoulus were over 1.5 GPa even near glass transition temperature. The complex viscosities of the resultant polymers melt maintained a narrow range of 308–313 Pas at 260 °C or 2700–4600 Pas at 340 °C during the testing time. That indicates the resultant resins have good melt flowability and stability. In addition, these poly(arylene ether)s were found to have good solubility in various solvents such as CHCl 3 , THF, NMP, DMAc, DMI, etc., and have good optical transmittance (>80%) at 450 nm. It suggests that the obtained poly(arylene ether)s not only can be processed by melt method, but also can be applied with solution method easily, and can be applied to tough and transparent films.
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高影响因子
LANGMUIR
·
2024
·
IF 3.7
Siyu Gan,Zhenxing Wang,Chunli Zheng,Zishen Lin,Ai-bin Zhu,Bo Lai
Commercial micron zerovalent iron (mZVI) and sulfur were used to prepare sulfidated micro zerovalent iron (S-mZVI) through ball milling. The corrosion potentials of mZVI and S-mZVI were −0.01 and −0.37 V, respectively, indicating S-mZVI possessed a stronger electron-donating ability. The practical antimony mine wastewater (C0(Sb(V)) = 3.8296 mg/L, pH = 8.29) was treated. If meeting the national discharge standard of 5 μg/L, 2.0 g/L mZVI and 1.6 g/L S-mZVI were required within 120 min. Passing N2 or reducing wastewater pH enhanced the treatment of Sb(V) by S-mZVI, in which the wastewater acidification was more effective. Once the wastewater pH was adjusted to 3.00, only 0.7 g/L S-mZVI and 40 min long time were needed to achieve the emission below 5 μg/L. Even S-mZVI underwent four cycles, and the final concentration of Sb(V) was as low as 4.67 μg/L. As the pHzpc value was 4.09 and the corrosion potential was −0.56 V at pH 3.0, the electron-donating ability of S-mZVI as well as the electrostatic attraction between the surface of S-mZVI and Sb(V) increased. Sulfidation of mZVI and then application under the acid condition significantly improved the treatment efficiency of Sb(V).
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高影响因子
APPLIED SURFACE SCIENCE
·
2025
·
IF 6.9
Muhammad Sabir,Mahmoud Sayed,Zhuofan Zeng,Bei Cheng,Wang Wang,Chuanbin Wang,Jingsan Xu,Shaowen Cao
The photocatalytic conversion of carbon dioxide (CO 2 ) into valuable products holds great promise from environmental and economic perspectives. However, current photocatalytic materials still exhibit unsatisfactory efficiency. In this study, a notably efficient step-scheme (S-scheme) heterojunction was developed by combining the Co-MOFs with carbon nitride nanosheets (g-C 3 N 4 ). The electrostatic interaction between these components not only facilitates the exfoliation of g-C 3 N 4 layers but also enhances the stability of the photocatalyst structure. The optimal heterojunction Co-CN4 photocatalyst achieved a significantly enhanced CO production rate of 16.1 µmol g −1 h −1 , which is 4.7 times higher than that of pure g-C 3 N 4 . This improved activity is ascribed to the enhanced light absorption and mitigated charge carrier recombination. Density functional theory (DFT) computations in conjunction with experimental observations elucidate the establishment of a close contact interface. Additionally, electron paramagnetic resonance (EPR) and in situ X-ray photoelectron spectroscopy (XPS) characterization unveil the electron transfer pathway of Co-CN4 during photocatalytic CO 2 conversion. This study offers valuable insights into the design of S-scheme photocatalysts for enhancement of CO 2 photoreduction.
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