NEW JOURNAL OF CHEMISTRY
·
2017
·Vol. 41
·期 5
·1953-1958
·
IF 3.269
Yulu Zhang,Jin Wang,Yong Wei,Xuetong Zhang
Molecular bridged silica aerogels have received extensive interest in recent years due to their easily controlled mechanical properties varying with different organosilane precursors, and without any further post-modification. In this work, a series of novel and robust molecular bridged silica aerogels were prepared by using a symmetrical urethane-bridged monomer, named N,N-bis(propyltriethoxysilyl)carbamide (bPTSCA), which was synthesized via a solvent-free exothermic reaction between 3-isocyanatopropyltriethoxysilane (IPTES) and 3-aminopropyltriethoxysilane (APTES) for several minutes at normal temperature and pressure. The influence of catalysts on the obtained gels and aerogels was studied in detail. It was found that NH4F aqueous solution showed the most effective catalysis capability, and the corresponding aerogels were intact with slight shrinkages. The mechanical strength of these aerogels could reach as high as 100 times more than that of the native silica aerogels (unbridged), and the strength could be easily adjusted from a rigid region to an elastic region simply by varying the sample density. Moreover, these aerogels possessed an interesting character of regional shrinking when encountering with water, which made it possible to fabricate artistic aerosculptures with water or other polar solvents as a graver.
研究领域:
材料科学
·
化学工程
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产品关联
DOI
高影响因子
ChemSusChem
·
2021
·Vol. 15
·期 4
·e202102455
·
IF 8.928
Xingwang Lan,Juan Wang,Qing Li,Aiqing Wang,Yize Zhang,Xianheng Yang,Guoyi Bai
Graphical Building bridges : Acetylene or vinylene-bridged π-conjugated covalent triazine polymers, A-CTP-DPA and V-CTP-DPE, are fabricated toward metal-free photocatalytic oxidation under visible light irradiation. Impressively, compared to the one without acetylene or vinylene bridge, A-CTP-DPA and V-CTP-DPE exhibit superior activity in photocatalytic selective oxidation of sulfides and oxidative coupling of amines. Solar-driven photocatalytic chemical transformation provides a sustainable strategy to produce valuable feedstock, but designing photocatalysts with high efficiency remains challenging. Herein, two acetylene- or vinylene-bridged π-conjugated covalent triazine polymers, A-CTP-DPA and V-CTP-DPE, were successfully fabricated toward metal-free photocatalytic oxidation under visible light irradiation. Compared to the one without acetylene or vinylene bridge, both resulting polymers exhibited superior activity in photocatalytic selective oxidation of sulfides and oxidative coupling of amines; in particular, A-CTP-DPA delivered an optimal photocatalytic performance. The superior activity was attributed to the broadened spectral response range, effective separation, rapid transportation of photogenerated charge carriers, and abundant active sites for photogenerated electrons due to the existence of the acetylene bridge in the framework. This work highlights the potential of acetylene and vinylene bridges in tuning catalytic efficiency of organic semiconductors, providing a guideline for the design of efficient photocatalysts.
研究领域:
材料科学
·
光化学
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产品关联
DOI
PubMed
高影响因子
Journal of Traffic and Transportation Engineering-English Edition
·
2022
·
IF 0
Gang Zhang,Xiaocui Zhao,Zelei Lu,Chaojie Song,Xuyang Li,Chenhao Tang
This paper presents an overview on fire behavior of bridge girders mainly including prestressed concrete (PC) bridge girders and steel bridge girders. The typical fire accidents occurred on bridges are illustrated and, the seriousness of posing threats to bridge structures resulted from increasing traffic fires, specially intense hydrocarbon fires generated from petrol-chemicals, is highlighted. The current researches, embracing high-temperature properties of constituent materials, prestress state, measurement in fire tests, numerical methods, structural fire resistance, and so forth, taken on coping with problems existing in fire behavior and structural fire behavior in bridge girders are reviewed and discussed. Further, strategies for enhancing fire resistance of bridge girders followed with failure criterion and mode in types of bridge structures are provided. Future research area along with emerging trends in structural fire behavior of bridge girders is also recommended for mitigating fire hazards occurred on bridge girders. Herein, it can be attained a conclusion from review and discussion that prestressed concrete bridge girders with thin webs, specially T-shaped bridge girder, are prone to unstable under fire exposure conditions. High-strength concrete utilized in prestressed concrete bridge girders is vulnerable to spalling at elevated temperature. Steel-truss bridge girder present a more significant fragility to fire exposure compared than other steel bridge girders.
研究领域:
土木工程
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结构工程
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材料科学
✓ 已验证
DOI
JOURNAL OF COORDINATION CHEMISTRY
·
2019
·
IF 1.685
Li-Zheng Cai,Wei Zhang,Zhao-Xia Zhu,Jing Ru,Min-Xia Yao
Three FeIII2LnIII2 tetranuclear heterometallic clusters, [H4LGd(H2O)Tp*Fe(CN)3]2·8H2O·2MeOH (1) and [H4LLn(MeOH)Tp*Fe(CN)3]2·6MeOH·2MeCN (Ln = Tb and Dy for 2 and 3, respectively, H6L = N,N′-(2,6-pyridine-dicarboxyl)-disalicylhydrazide, Tp* = hydridotris(3,5dimethylpyrazol-1-yl)-borate), were synthesized by use of the [(Tp*)Fe(CN)3]− unit as a metalloligand toward LnCl3 and H6L species. Structural analyses reveal that FeIII and LnIII ions in all complexes are connected to each other by one cyanide to form a heterobinuclear unit of [Ln(H4L)][(Tp*)Fe(CN)3], which is dimerized through Ln–N–C = O–Ln interaction. Magnetic susceptibility measurements show weak antiferromagnetic interactions between cyano-bridged FeIII and GdIII ions and amide-bridged GdIII ions are operative. Complex 1 displays the magnetocaloric effect with −ΔSmmax = 12.70 J·kg−1·K−1 at 4.0 K for ΔH = 7 T. No single-molecule magnetic properties are observed for 2 or 3 down to 1.8 K.
研究领域:
无机化学
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材料科学
·
磁学
✓ 已验证
DOI
高影响因子
ADVANCED FUNCTIONAL MATERIALS
·
2024
·
IF 18.5
Wenxin Wang,Ruidong Yang,Qiqi Mao,Xu Mu,Hongjie Yu,Kai Deng,Jianguo Wang,Liang Wang,Hongjing Wang
The utilization of green hydrogen sources in H 2 O for alkynols electrocatalytic semihydrogenation reaction (ESHR) at ambient temperature provides a promising pathway toward the sustainable conversion of alkynols. However, it is still a great challenge to construct specific interfacial structure to adjust the electronic structure of Pd for the purpose of altering the strong adsorption of Pd with active hydrogen to enhance the production of alkenols. Here, the atomically dispersed GaO x -PdMo bimetallene nanoribbons (GaO x -PdMo BNRs) via oxygen bridging Ga atoms is designed to the surface of PdMo BNRs for 2-methyl-3-butyn-2-ol (MBY) ESHR to the synthesis of 2-methyl-3-buten-2-ol (MBE). The GaO x -PdMo BNRs achieve the excellent MBE selectivity (≈97.4%), Faraday efficiency (≈96.1%), and maintain long-term stability. Density functional theory demonstrates that the top electron-enriched Ga atoms and the bottom electron-deficient Pd atoms construct a “pyramidal” interface via the oxygen bridge. The unique surface can effectively activate H 2 O and weaken interaction between catalyst and MBE, thus promoting MBE generation. Moreover, the electron bridge effect between Ga-O-PdMo can induce p-d orbital hybridization to achieve lower the d -band center of surface Pd thus modulating the reactants adsorption. This work provides a strategy to improve ESHR performance by electron bridge effect to modulate interfacial electron distribution.
研究领域:
材料科学
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催化化学
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理论计算
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产品关联
DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2024
·
IF 12.2
Qi Li,Dejun Sun,Feng Chen,Haoran Xu,Zhenghe Xu
Hydrothermal treatment (HT) can effectively dehydrate and reduce oily sludge (OS) volume, but the resulting hydrothermal oily sludge (HOS) presents greater challenges for washing than the initial oily sludge (IOS). This study examines the effects of HT on OS by analyzing changes in water, oil, and solid. Results indicate that HT considerably decreases the water content in OS while increasing resin and asphaltenes contents. In addition, condensation, side-chain scission, and oxidation reactions occur during the HT process, resulting in coking, agglomeration, and an increase in oxygen-containing groups. This increase, further confirmed by X-ray photoelectron spectroscopy (XPS), enhances the interaction between oil and solids. Calcite, the most prevalent solid-phase component, may form a calcium bridge with the oxygen-containing groups. Moreover, HT reduces the solid particle size, thereby increasing the oil–solid contact area. Interestingly, the process of deasphalting diminishes the interaction between oil and solids, facilitating sludge washing. After washing, the residual oil content in HOS is reduced to less than 0.34%. This study elucidates why HOS is challenging to separate from oil and solids and introduces a novel method that combines dodecylbenzene sulfonic acid (DBSA)-assisted heptane deasphalting with conventional washing techniques. This method shows promise for applications in OS affected by weathering processes.
研究领域:
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
APPLIED CLAY SCIENCE
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2022
·
IF 5.907
Fayang Guo,Dabao Li,Jeremy B. Fein,Jingcheng Xu,Yingwei Wang,Qiaoyun Huang,Xingmin Rong
Reactions occurring at silicate minerals play a significant role in controlling phenolic endocrine disrupting chemicals' bioavailability and mobility. However, the underlying molecular mechanisms for BPA (bisphenol A) and BPS (bisphenol S) onto montmorillonite (MMT) remain poorly understood. To decipher the molecular-level interfacial configuration and dominant reaction mechanism, batch experiments, X-ray diffraction (XRD), Fourier transform infrared spectrum (FTIR), X-ray photoelectron spectroscopy (XPS) measurements, and density functional theory (DFT) calculations were performed. Our batch adsorption experiments showed that MMT exhibits a higher adsorption capacity for BPS than for BPA. The XRD analysis also suggested that BPA and BPS could enter the interlayer of MMT. FTIR and XPS results revealed that The Ca atoms and the oxygen atoms in the SiO 4 tetrahedra were involved in BPA and BPS adsorption process via non-covalent interactions. The electrostatic potential calculations suggested that the sulfonyl O site and the hydroxyl H site on the BPS molecule are more favorable for interacting with the MMT surface than the hydroxyl O and H sites of the BPA molecule. DFT calculations further confirmed that stronger binding of BPS than BPA onto the (001) surface and the interlayer of MMT. BPA tends to form Ca ion bridges through hydroxyl groups onto MMT. In contrast, BPS prefers to form Ca ion bridges onto MMT through its sulfonyl group and form hydrogen bonds via hydroxyl groups. This study provides new insights into the molecular-scale interactions that control BPA and BPS adsorption onto an important and environmentally-relevant clay mineral, and which affect the fate and behavior of BPA and BPS in soil systems.
研究领域:
环境科学
·
分子生物学
✓ 已验证
DOI
高影响因子
JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY
·
2025
·
IF 6.2
Yuzhu Zhang,Hao Wu,Zheng Fu,Shilong Zhang,Meiling Zheng,Jiaxia Sun,Zhongxia Lu,Rilei Yu,Wengong Yu,Feng Han
Hyaluronate lyases are widely used in medicine and biochemical engineering and are also applied as a tool enzyme to prepare oligosaccharides with various biological activities. To date, only a few hyaluronate lyases are on sale with poor thermostability. In this study, a PL8 hyaluronate lyase, TcHly8D, was found from Thermasporomyces composti and expressed in Escherichia coli with a maximum yield of 1.77 × 109 U/L (3.14 g/L) in a 5-L bioreactor. The recombinant TcHly8D exhibited a high hyaluronate lyase activity of 5.64 × 105 U/mg and an excellent thermostability with half-lives of 184.9 h at 60 °C. Fifty micrograms of TcHly8D could catalyze 5 g of hyaluronic acid with an oligosaccharide yield of 84.8% in 4 h. The salt bridges, hydrogen bonds, and proline residues, but not disulfide bonds, played important roles in the thermostability of TcHly8D. These findings provide insights into the multifunctional application potential of TcHly8D in agriculture, medicine, and the food industry.
研究领域:
生物化学
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医学
·
酶工程
✓ 已验证
DOI
PubMed
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2024
·
IF 4.9
Ruifeng Zhou,Jiaqi Zhao,Liang Chen,Jingyang Zhang,Zehui Fan,Chong Peng,Yun Li,Shuyi Yang,E Tao
ABSTRACT The intrinsic correlation between photo-induced extraction of hole and free radical reactions can facilitate the mineralization of contaminants via promoting the transfer of electrons from the semiconductor to the solution. TiO 2 /C/g-C 3 N 4 composite photocatalysts are prepared using thermal polycondensation and sol-gel methods in this paper. The introduction of carbon at the interface between the two phases creates charge migration channels that facilitate electron transfer at the interface of semiconductor catalyst as well as collisions of dissolved oxygen to the catalytic sites, which are able to promote catalytic oxidation reactions. Considering Rh-B as target, the removal rate is 97.2±0.2% within 90 min. The involvement of hydroxyl radicals and superoxide radicals is confirmed by carrying out radical quenching experiments and ESR characterization, suggesting that effective electron transfer synergistically promotes the production of hydroxyl radicals. Therefore, it emphasizes the importance of the indeterminate carbon bridged 2D/3D interface for constructing charge migration channels as well as promoting the efficiency of carrier separation in the process of photocatalytic efficient degradation of dyes.
研究领域:
环境科学
·
材料科学
✓ 已验证
DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2025
·
IF 7.2
Nuo Zhang,Bingzhu Wang,Pengcheng Hu,Zhenxing Gao,Haiwang Wang
MCNTs-CdS has been identified as a promising material for photocatalytic hydrogen production due to its strong visible-light responsiveness and suitable energy band structure. However, the rapid complexation of its photogenerated electrons and holes makes its photocatalytic hydrogen production unsatisfactory. To address the above problem, MCNTs-CdS/Pt/ZnFe 2 O 4 composites were designed in this paper, and Pt was used as an electronic bridge to realize the fast transfer of electrons between the two semiconductors. The results show that the carrier transport resistance of MCNTs-CdS/Pt/ZnFe 2 O 4 system is greatly reduced, and the electron-hole separation rate is significantly better than that of MCNTs-CdS. In addition, the results of the photolysis of water hydrogen production demonstrated that when the deposition amount of Pt was 8 % and the mass ratio of MCNTs-CdS to ZnFe 2 O 4 was 1:0.1, the hydrogen production rate reached its maximum (1100.82 μmol/g/h), which was 35.51 times higher than that of MCNTs-CdS. The metal Pt functions as an electronic bridge to realize rapid electron transfer and MCNTs-CdS/Pt/ZnFe 2 O 4 form a Z-scheme carrier transport mechanism.
研究领域:
材料科学
·
能源科学
·
纳米技术
✓ 已验证
产品关联
DOI
高影响因子
INORGANICA CHIMICA ACTA
·
2022
·
IF 3.118
Xinghao Han,Bin Liu,Zhihong Wang,Alexander Ross Craze,Hongxia Sun,Misbha Rafiq Khan,Jing Liu,Zhongyi Liu,Jinpeng Li
Based on asymmetric lithium salts of 1-(2-pyridinylmethyl)-pyrazole-3,5-dicarboxylate (2-Li 2 pmpd) or 1-(4-pyridinylmethyl)-pyrazole-3,5-dicarboxylate (4-Li 2 pmpd), four polymers [Mn(2-pmpd)(H 2 O)] n (1), {[Mn 2 (4-pmpd)(pd)(H 2 O) 3 ]·H 2 O} n (2), [Co(4-pmpd)(H 2 O)] n (3) and [Co(2-pmpd)(H 2 O) 2 ] n (4) [pd = pyrazole-3,5-dicarboxylate] have been hydrothermally prepared and characterized structurally. 1 displays three-dimensional (3D) network with (4 4 .8 4 ) topology, 2 and 3 show 2D framework with (4 2 ·5·6 3 )(4 2 ·5 2 ·6 4 ·7 2 )(5 2 ·8) and (4 3 ) 2 (4 6 ·6 6 ·8 3 ) topologies, respectively. 4 is a 1D chain structure. Magnetization data of 1 with the 1D carboxylate bridges chain structure, fitted by the 1D model, suggests the antiferromagnetic coupling with J = −2.07 cm −1 . The carboxylate bridges in 1 adopt common syn - syn and unidentate oxygen-bridge modes. 2 with the Mn 4 unit, exhibits antiferromagnetic coupling with J = −0.68 cm −1 and z J ′ = −0.317 cm −1 . The carboxylate bridges in 2 adopt common syn - anti and the unidentate oxygen-bridge modes. In the Co 2 units, magnetization data for 3 shows the weak antiferromagnetic coupling. Variable temperature magnetic studies of 4 reveal ferromagnetic intrachain interactions and antiferromagnetic interchain magnetization interactions. The M ( H ) curves for 3 and 4 are consistent with their antiferromagnetic or ferromagnetic natures.
研究领域:
无机化学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
POLYMER DEGRADATION AND STABILITY
·
2016
·
IF 3.12
Bin Zhao,Wen-Jun Liang,Jun-Sheng Wang,Fei Li,Ya-Qing Liu
A novel flame retardant , named bisphenol-A bridged penta(anilino)cyclotriphosphazene (BPA-BPP), was successfully synthesized. Its chemical structure was characterized by Fourier transform infrared (FTIR), 1 H NMR and 31 P NMR. Then, different amounts of BPA-BPP were mixed with diglycidyl ether of bisphenol-A (DGEBA) to fabricate flame retardant epoxy resin (EP). Nonisothermal differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) tests were used to study the curing kinetics and thermal degradation behaviors of flame retardant EPs. The results of limiting oxygen index (LOI), vertical burning tests (UL-94) suggested that BPA-BPP exhibited good flame-retarded efficiency on the EP loaded with low phosphorus content. Compared with the neat EP, the LOI value of EP/9%BPA-BPP increased from 21.0 vol% to 28.7 vol%. Furthermore, the peak of heat release rate (PHRR), total heat release (THR), total smoke production (TSP) of the same sample, obtained from cone calorimetry, were declined obviously, suggesting excellent flame retardancy and smoke inhibition. The morphology and chemical structures of the char layers were analyzed by SEM, Raman and FTIR. The Py-GC/MS was used to investigate the pyrolysis behavior and flame-retardant mechanism of BPA-BPP. In the process of heating, aniline, diphenylamine and NH 3 were released from BPA-BPP in gaseous phase, and phosphorus-rich carbonaceous chars were left in condensed phase. BPA-BPP could promote EP to form intumencent protective char layers, enhancing flame retardancy of EP effectively.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）