CEMENT AND CONCRETE RESEARCH
·
2020
·
IF 8.328
Xin Liu,Pan Feng,Wei Li,Guoqing Geng,Jiale Huang,Yun Gao,Song Mu,Jinxiang Hong
Calcium silicate hydrate (C-S-H), the most important Portland cement hydration product , determines the mechanical properties and durability of cementitious materials . In marine environment, C-S-H often suffers from sulfate attack – one of the most common and severe degradations for concrete. pH is considered as a critical factor in determining the deterioration behavior of C-S-H during sulfate attack, of which the significance may be overlooked. This study focused on the role of pH on the deterioration of C-S-H in terms of the composition and nano/micro structure under sulfate attack. The results show that lowering pH aggravates the decalcification of C-S-H, whereas a strong alkaline condition is beneficial to increase the resistance to deterioration. An increase in the mean chain length together with the proportion of large pores (>10 nm) is observed when C-S-H is subjected to low-pH sulfate attack (pH = 10–12), resulting in a relatively loose structure. The deep analysis on defective tobermorite model reveals that calcium at the interlayer of C-S-H nanostructure is readily removed under sulfate attack, thereby improving the potential of Si-O-Si groups formation and increases the mean chain length of C-S-H.
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ACS Applied Energy Materials
·
2020
·
IF 4.473
Yiming Wang,Yanchun Yang,Chengjun Zhu,Hongmei Luan,Ruijian Liu,Lei Wang,Chenxi Zhao,Xiaogong Lv
Substitution of Zn with Mg has been reported to suppress CuZn defects, which can improve the photoelectric performance of Cu2ZnSn(S,Se)4 (CZTSSe) photovoltaic devices. In our work, the electrical property enhancement of an absorbing layer can be found by incorporating Mg content into the as-prepared precursor solution, forming an alloyed Cu2MgxZn1-xSn(S,Se)4 (CMZTSSe) phase and increasing the photoelectric performance of devices. By adjusting the doping ratio of Mg, we systemically study the impact of Mg content on the crystal structure, thickness, and electrical properties of the Cu2MgxZn1-xSn(S,Se)4 absorbing layer. Also, the photoelectric performance of Cu2MgxZn1-xSn(S,Se)4 solar cells have a large improvement, and the optimal photoelectric conversion efficiency (PCE) of 7.76% for devices is obtained. Our results offer the finding that Mg doping can optimize the electrical properties of Cu2ZnSn(S,Se)4 photovoltaic devices.
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Nanomaterials
·
2020
·Vol. 10
·期 9
·1633
·
IF 4.324
Zhi Zhang,Zichuan Yi,Liming Liu,Jianjun Yang,Chongfu Zhang,Xinjian Pan,Feng Chi
Lithium-sulfur battery (LSB) will become the next generation energy storage device if its severe shuttle effect and sluggish redox kinetics can be effectively addressed. Here, a unique three-dimensional hollow reduced graphene oxide microsphere decorated with ZnO nanoparticles (3D-ZnO/rGO) is synthesized to decrease the dissolution of lithium polysulfide (LiPS) into the electrolyte. The chemical adsorption of ZnO on LiPS is combined with the physical adsorption of 3D-rGO microsphere to synergistically suppress the shuttle effect. The obtained 3D-ZnO/rGO can provide sufficient space for sulfur storage, and effectively alleviate the repeated volume changes of sulfur during the cycle. When the prepared S-3D-ZnO/rGO was used as the cathode in LSB, an initial discharge specific capacity of 1277 mAh g−1was achieved at 0.1 C. After 100 cycles, 949 mAh g−1can still be maintained. Even at 1 C, a reversible discharge specific capacity of 726 mAh g−1was delivered.Keywords:ZnO;graphene;spray drying;hollow structure;lithium-sulfur battery
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Journal of Materials Chemistry A
·
2020
·Vol. 8
·期 39
·20604-20611
·
IF 11.301
Liang-Liang Gu,Jian Gao,Chuang Wang,Sheng-You Qiu,Ke-Xin Wang,Xiao-Tian Gao,Ke-Ning Sun,Peng-Jian Zuo,Xiao-Dong Zhu
Lithium–sulfur (Li–S) batteries are regarded as one of the most promising candidates for next-generation energy storage systems due to their advantages of its high specific capacity and low material cost. Regrettably, the electrical insulation nature of sulfur, the volume expansion during lithiation, and the internal shuttle effect aroused by the polysulfides dissolution are the central issues for sulfur cathodes. Here, CoFe2O4@C nanocages derived from Prussian blue analogues and polydopamine were utilized as a sulfur host to address these problems. The polar Co–Fe oxide afforded chemical adsorption sites for anchoring polysulfides to reduce the shuttling effect. The hollow core structure of the nanocages could withstand the large volume change during lithiation and delithiation processes. The conductive carbon layer on the nanocages could ameliorate the extremely low electrical conductivity of S and Li2S. The S/CoFe2O4@C cathode demonstrated high capacity and excellent cyclability (821 mA h g−1 after 100 cycles at 0.5C). More importantly, the combinational strategies of good conductivity, physical space encapsulation, and chemical adsorption provide a means of resolving the current cathode issues in Li–S batteries.
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Materials Today Energy
·
2020
·
IF 5.604
L. Zheng,W. Zhang,B. Gao,H. Lu,X. Fan,Y. Zhang,Y. Wang,S. Wang,Q. Gao,Y. Tang
Transition metal dichalcogenides (TMDs) are regarded as the inexpensive and stable electrocatalysts for hydrogen evolution reaction (HER). Designing an electrocatalyst with few-layered molybdenum disulfide (MoS 2 ) is one of the most effective methods to enhance the activity and durability for HER due to its abundant exposed rim-sites, fast electron transfer and high chemical stability. Herein, a green and facile one-pot approach is developed to synthesize few-layered MoS 2 /nitrogen, sulfur codoped porous carbon (MoS 2 /NSPC) electrocatalyst via pyrolyzing the in-situ formed molybdate-melamine complex (MoO x -MEL) within the self-assembled networks of melamine-trithiocyanuric acid (MT). The optimal MoS 2 /NSPC electrocatalyst exhibits excellent HER stability and activity with overpotential of 114 mV at 10 mA cm −2 in 0.5 M H 2 SO 4 . Furthermore, few-layered tungsten disulfide anchored on N, S-codoped porous carbon (WS 2 /NSPC) with high HER activity can also be successfully synthesized by this strategy. It paves a universal way to design active sites–enriched few-layered dichalcogenides with high performance in the applications from energy conversion to storages.
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POLYMER ENGINEERING AND SCIENCE
·
2020
·Vol. 61
·期 2
·379-387
·
IF 1.917
Jing Jing,Li Song,Tingting Su,Zhanyong Wang
In this study, various biodegradable materials, including poly(butylene succinate) (PBS), poly(hexamethylene succinate) (PHS), and poly(butylene succinate- co -hexamethylene succinate)s (P[BS- co -HS]s) containing different hexamethylene succinate (HS) contents, were prepared. The compositions, thermal properties, mechanical properties, hydrophilicity, and enzymatic hydrolyzability of the materials were investigated by various techniques. The results showed that the composition of the copolyesters was similar to the feeding ratio of the reactants. The melting and crystallization temperatures, thermal stability, and degree of crystallinity of the copolyesters decreased for low HS content and increased for high HS content. P(BS- co -HS)s containing 52 mol% HS exhibited low crystallization temperature ( T c ), melting temperature ( T m ), degree of crystallinity ( X c ), and high hydrophilicity, elongation at break and enzymatic hydrolyzability. We also observed that low degree of crystallinity and high crystal defects, hydrophilicity, and high elongation at break could improve the enzymatic hydrolyzability of the materials.
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ELECTROANALYSIS
·
2020
·Vol. 32
·期 8
·1772-1779
·
IF 2.544
Yifei Yang,Yue Sun,Mingzhu Jin,Ru Bai,Yutong Liu,Yingqi Wu,Wei Wang,Xuewei Feng,Siyu Li
Superoxide dismutase (SOD) plays an important role in nearly all living cells. In this study, SOD imprinted poly(ionic liquid)s (SIPILs) were prepared on the surface of the bare Au electrode modified with nano-palladium and nano-gold (Au/nPd/nAu/SIPILs). SIPILs was synthesized with 1-vinyl-3-propyl imidazole sulfonate ionic liquids as functional monomers via electrochemically mediated atom transfer radical polymerization (eATRP) catalyzed by SOD. The Au/nPd/nAu/SIPILs was examined by cyclic voltammetry (CV), scanning electron microscope (SEM), energy-dispersive spectrometer (EDS) and X-ray photoelectron spectroscopy (XPS). The Au/nPd/nAu/SIPILs was also used as an electrochemical sensor to determine SOD by differential pulse voltammetry (DPV). Under the optimal conditions, the detection range of SOD was from 1.0×10 −8 to 1.0×10 2 mg L −1 with a limit of detection of 8.90×10 −9 mg L −1 (S/N=3). Compared with other methods, the sensor based on SIPILs had the broader linear range and lower detection limit.
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Alexandria Engineering Journal
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2020
·
IF 2.46
Saifeldin M. Siddeeg,Abdelfattah Amari,Mohamed A. Tahoon,Norah Salem Alsaiari,Faouzi Ben Rebah
For the simultaneous removal of water contaminants, a novel nanocomposite has been produced. The iron oxide core with silica shell was used to prepare functional magnetic polymer Fe 3 O 4 /SiO 2 /glycidyl methacrylate (GMA)-S-SH nanocomposite. The sulfur functional nanocomposite is suitable for the immobilization of laccase enzyme. The synthesized nanocomposite was characterized using FT-IR spectroscopy, SEM, TEM, XRD, and magnetometer. The effect of pH, temperature, and storage time over free and immobilized enzyme was studied that indicating the higher stability of immobilized enzyme than that free one. The prepared novel nanocomposite showed high adsorption capacity toward Cd +2 ions in addition to the degradation of meloxicam and piroxicam anti-inflammatory drugs. The removal efficiency reached up to 94% ± 2%, 92% ± 2%, and 95% ± 2% for Cd +2 ions, meloxicam, and piroxicam, respectively at optimum pH and temperature. Also, the results show that this nanocomposite is recyclable. The efficient removal of Cd +2 ions and pharmaceuticals can be reached up to four cycles. We conclude that the prepared nanocomposite is promising for water treatment.
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BIOMEDICAL CHROMATOGRAPHY
·
2020
·Vol. 34
·期 7
·e4834
·
IF 1.728
Xiaoyue Shan,Siwei Tan,Yanpeng Shi,Ji Shao,Kewen Su,Ling Zhang,Hui Feng,Haipeng Ye
In this study, activated carbon/diatomite-based magnetic nancomposites (denoted as AC/DBMNs) were synthesized and applied as an adsorbent for magnetic solid-phase extraction of S- phenylmercapturic acid ( S- PMA) from human urine prior to high-performance liquid chromatography. The surface morphologies and structures of AC/DBMNs were characterized by Fourier transform infrared spectroscopy, transmission and scanning electron microscopy, X-ray diffraction, Brunauer–Emmett–Teller surface area, vibrating sample magnetometer and ζ -potential measurements. The experimental parameters including sample volume, sample pH, adsorbent amount, extraction time, elution solvent and desorption time were investigated in detail. Under the optimum conditions, the method exhibited good linearity ( r > 0.9993) within the concentration ranges of 0.03–1.0 mg/L. Moreover, the limits of detection and quantification were 0.01 and 0.03 mg/L, respectively. The enrichment factor was 5, and good recoveries (88.9–97.3%) with relative standard deviations in the range of 5.6–6.8% ( n = 6) for inter-day and 6.3–8.1% ( n = 6) for intra-day were achieved. The developed method was successfully applied to the analysis of S- PMA in urine samples. In addition, this accurate and sensitive method has great potential to be applied in the early screening and clinical diagnosis of the workers exposed to benzene.
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JOURNAL OF ALLOYS AND COMPOUNDS
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2020
·
IF 4.65
Junli Wang,Lei Jin,Tingting Wang,Lijun Zhao,Fan Guan,Shaopeng Li,Dan Wang,Junhao Zhang
We report the ethylene glycol-mediated solvothermal synthesis of the continuous solid solution (Sb 1-x Bi x ) 2 S 3 (0 < x < 1) with 1D nanostructures (nanowires and nanorods). The ternary products show a broad variation in Bi:Sb composition ratios (53:47–7:93), length-to-diameter aspect ratios (2.7–66.2), and optical bandgap energies (1.36–1.55 eV) as well as an enhanced photocurrent (e.g., (Sb 1-x Bi x ) 2 S 3 with x = 0.22 is three times higher than pure Sb 2 S 3 ). The gradual shift of peak positions in the XRD patterns and the uniform distributions of Bi, Sb and S elements in EDS mapping prove the formation of single-phase (Sb 1-x Bi x ) 2 S 3 solid solution. Its formation is due to an isostructure-favored alloying mechanism, since Sb 2 S 3 and Bi 2 S 3 possess the same orthorhombic structure (space group: Pnma) and the similar lattice constants . The substitution of Bi for Sb isovalent cations can shorten the lengths of ternary alloyed Sb–Bi–S nanowires and transfer them to low aspect-ratio nanorods at high Bi/Sb precursor ratios. The dependence of the lengths on Bi/Sb ratios is reasonably interpreted considering the differences in the number of nuclei at different amounts of Bi ions and the covalency of Bi–S and Sb–S bonds during the alloying process.
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JOURNAL OF HAZARDOUS MATERIALS
·
2020
·
IF 9.038
Yingxin Chen,Yun Ling,Xinyu Li,Jiani Hu,Chengjin Cao,Defu He
Microplastics (MPs) are persistent contaminants in aquatic environments. Microalgae, as the main phytoplankton and primary producers, usually co-exist with MPs. Despite previous studies that have proved the interaction of MPs and microalgae, it is largely unknown whether MPs can be uptake into cells of microalgae. In this study, both marine P. helgolandica var. tsingtaoensis and freshwater microalgae S. quadricauda were respectively exposed to 10 mg/L polystyrene microbeads with five diameter sizes: 1.0, 2.0, 3.0, 4.0, and 5.0 μm. Confocal laser scanning and 3D image analysis showed that mean 24.0 % or 11.3 % cells of P. helgolandica var. tsingtaoensis contained 1.0 μm or 2.0 μm MPs after 72 h exposure. While mean 43.3 % or 15.3 % of S. quadricauda individuals engulfed 1.0 μm or 2.0 μm MPs within cells. But, none of 3.0–5.0 μm MPs were observed within algal cells. These results demonstrate the size-dependent cellular internalization of MPs in microalgae. Exposure to 1.0–2.0 μm PS MPs caused a significant reduction in the density of microalgae and influenced photosynthesis, which suggests cellular internalization of MPs can influence algal fertility and growth. This discovery first confirms cellular internalization of MPs in phytoplankton, of significance for the fate and eco-toxicity of MPs in the aquatic ecosystem.
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RSC Advances
·
2020
·Vol. 10
·期 41
·24425-24433
·
IF 3.119
Shenjie Li,Tianyong Zha,Xiaoyu Gong,Qi Hu,Minghui Yu,Jinyu Wu,Ruolan Li,Jiaming Wang,Yanyan Chen
We present a facile route for the synthesis of water-soluble Cu–Cd–Zn–S/ZnS core/shell quantum dots (QDs) by simple pH regulation. The PL spectra of Cu–Cd–Zn–S/ZnS core/shell quantum dots can cover the whole visible light region in the case of only two ratios of Cu/Cd/Zn. The emission wavelength of Cu–Cd–Zn–S/ZnS QDs can be conveniently tuned from 474 to 515 and 548 to 629 nm by adjusting the pH value when the ratios of Cu/Cd/Zn are fixed at 1 : 5 : 80 and 1 : 5 : 10, respectively. It is worth noting that under the condition of a constant Cu/Cd/Zn ratio, the UV-vis absorption spectra do not change with the fluorescence spectra, indicating that the band gap of QDs remains unchanged during the change of pH value. The photoluminescence (PL) quantum yield of the as-prepared QDs with yellow emission is up to 76%. The QDs also show excellent chemical stability after the deposition of the ZnS shell. Luminescent and flexible films are fabricated by combining Cu–Cd–Zn–S QDs with polyvinyl alcohol (PVA). The QD/PVA flexible hybrid films are successfully applied on top of a conventional blue InGaN chip for remote-type warm-white LEDs. As-fabricated warm-white LEDs exhibit a higher color rendering index (CRI) of about 89.2 and a correlated color temperature (CCT) of 4308 K.
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