Catalysts
·
2022
·Vol. 12
·期 7
·685
·
IF 4.501
Hao Dong,Cheng-Hua Xu,Fang-Lu Yang,Lei Du,Chen-Long Liu,Wen-Jing Chen,Lin Wang
Ca–Zr–Sn composite oxides catalysts for 1,4-butanediol (BDO) selective dehydration to 3-butene-1-ol (BTO) are synthesized by impregnation and co-precipitation in the present work. The results show that Ca–Zr–Sn catalysts prepared from co-precipitation by using NaOH-Na2CO3mixing alkali solution as precipitant exhibit an excellent catalytic property for BDO dehydration to BTO. For instance, Ca–Zr–Sn oxide with Ca/Zr and Sn/Zr molar ratio of 0.68 and 0.28 calcined at 650 °C gives a BDO conversion and BTO selectivity of about 97% and 82%, respectively, and exhibits no deactivation during 1000 h scale-up experimental testing. X-ray diffraction results indicate that catalytic active centers for BDO dehydration to BTO are from Ca0.15Zr0.85O crystal phase. NH3- and CO2-temperature programmed desorption prove that the surface of obtained catalysts can provide a large amount of acid and base sites simultaneously. FT-IR spectra of pyridine-adsorbed samples show that acid sites on the surface of Ca–Zr–Sn oxide catalyst mainly exist in a state of Lewis acid, which activates terminal -OH groups of BDO molecule through complexing. The activated -OH interacts with β-H activated on base sites O2−anions relative to Ca species, thereby the CH2=CH- bonds are produced through dehydration to form BTO.
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JOURNAL OF STRUCTURAL CHEMISTRY
·
2022
·Vol. 63
·期 6
·845-853
·
IF 1.004
Chen X.,Gao R. -L.,Li B.,Wang H. -M.
Abstract Reaction of SmCl 3 ·6H 2 O with 3 equiv. of dihydroxodiphenylarsonium chloride [Ph 2 As(OH) 2 ]Cl resulted in the first structurally characterized lanthanide complex of organoarsinate [Sm(μ-O 2 AsPh 2 ) 3 ]. Single crystal X-ray diffraction reveals that this complex belongs to the trigonal system, \(R\bar{3}\) space group, with a = 24.077(3) Å, b = 24.077(3) Å, c = 10.708(1) Å, β = 120°, V = 5375.8(1) Å 3 and Z = 6. This homoleptic compound features a 1D polymer arrangement in which two Sm atoms are bridged by three diphenylarsinate [Ph 2 AsO 2 ] – ligands under syn,syn μ 2 –η 1 :η 1 bridging mode. The coordination number of Sm center is 6, giving an almost perfect octahedron geometry. The antibacterial activity of [Sm(μ-O 2 AsPh 2 ) 3 ] is much weaker than the free ligand [Ph 2 As(OH) 2 ]Cl.
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FOOD HYDROCOLLOIDS
·
2022
·
IF 11.504
Shan Qian,Lin Chen,Zhengshan Zhao,Xiaojing Fan,Xinglian Xu,Guanghong Zhou,Beiwei Zhu,Niamat Ullah,Xianchao Feng
Ovalbumin (OVA), is the most abundant protein in the egg white. In the present study, the effects of Epigallocatechin-3-gallate (EGCG) on the self-assembly behavior and gelling properties of OVA with different heating time were investigated. Electrophoresis , surface hydrophobicity, Fourier transform infrared (FTIR) spectroscopy and molecular docking analysis indicated that hydrophobic force and hydrogen bond were the predominant interactions between EGCG and OVA. The binding of EGCG to OVA suppressed the formation of fibrils as evidenced by the results of Thioflavin T (ThT) intensity and atomic force microscopy (AFM) analysis. When heated for 15–30 min, EGCG addition, especially at 2.5 μM/g, resulted in a decrease of ThT fluorescence intensity and hydrophobicity of OVA samples, and a formation of dense linear aggregates. However, the OVA solution did not form a gel. In a longer heating time of 45 min, 5 μM/g EGCG induced a significant decrease in ThT fluorescence intensity and hydrophobicity of OVA samples, and a transition from the dense linear aggregates to the dense spherical clusters. Therefore, the OVA samples realized the transition from the solution state to the gel state with a higher storage modulus (G′). When the heating time was extended to 60 min, all the OVA samples formed gel and reached the highest G′ at 5 μM/g EGCG. These results suggested that the suitable hydrophobic interactions and hydrogen bonds between EGCG and the OVA improved gel quality. Polyphenol binding provided a new way to regulate the assembly behavior and gelling properties of OVA.
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ChemElectroChem
·
2019
·Vol. 6
·期 17
·4681-4688
·
IF 3.975
Yu Huang,Rengui Xiao,Zhiming Ma,Weichen Zhu
Graphical In sync : The 1-ethyl-3-methylimidazolium trifluoromethanesulfonate (EMImTfO) dual-graphite battery exhibits a high discharge plateau above 3.0 V, which originates from the synchronized de-intercalations of EMIm + and TfO − from the graphite cathode and anode, respectively. The battery can light up a red LED with 3.0 V standard voltage. In this work, a novel dual-graphite battery (DGB) based on a pure 1-ethyl-3-methylimidazolium trifluoromethanesulfonate (EMImTfO) ionic liquid electrolyte is constructed. Within a charge/discharge voltage range of 1.0–3.9 V and at a current of 400 mA g −1 , batteries with dual-natural-graphite electrodes exhibit a high discharge plateau above 3.0 V with an initial discharge capacity of 46.2 mAh g −1 , delivering a capacity retention of 71.0 % after 100 cycles. Comparative studies between the natural graphite and the synthetic graphite (KS6) electrodes are also conducted. Charge-discharge tests reveal that the dual natural-graphite battery presents a higher discharge voltage plateau and better retention than the dual KS6-graphite battery. To confirm the principle of the dual-graphite systems, a cyclic voltammetry test is conducted. The results demonstrate that the EMIm + cation exhibits an even more stable intercalation/de-intercalation behavior than the TfO − anion. Further tests, including ex situ X-ray diffraction and ex situ Raman spectroscopy, are performed to reveal the mechanism of TfO − and EMIm + intercalation into graphite, both demonstrating a reversible process.
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JOURNAL OF POWER SOURCES
·
2021
·
IF 9.127
Xiaochen Wang,Hualong Ma,Hanqing Peng,Yingming Wang,Gongwei Wang,Li Xiao,Juntao Lu,Lin Zhuang
H 2 –O 2 polymer electrolyte fuel cells (PEFCs) represent one of the most promising next generation renewable energy conversion technologies. Two of the remaining unsolved key issues relate to inefficient mass transport and water management when working at high current densities . These problems arise from the structure of the existing flow fields and gas diffusion layers (GDLs), as well as the counter propagating flow directions of gas reactants and liquid products. To address these issues, we propose a novel design of an integrated flow field-gas diffusion layer ( i -FF-GDL) generated by 3D printing of TiH 2 followed by high temperature decomposition . In this new i -FF-GDL design, a porous Ti “bone” structure is used to drive water transport through capillary action , while regularly printed gaps transport gases. Benefiting from the separate gas and liquid flow channels, APEFCs using our i -FF-GDL design exhibit up to a 15% increase in peak power density (PPD) under H 2 -air (CO 2 free) and H 2 –O 2 conditions, when compared to traditional APEFCs. Operando electrochemical impedance spectroscopy (EIS) reveals that the enhanced performance arises largely from an increase in the mass transport. This work provides new insights and strategies for achieving high efficiency mass transport for fuel cells, water electrolyzers and related technologies.
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JOURNAL OF POWER SOURCES
·
2016
·
IF 6.333
Xiaolei Jiang,Huayun Xu,Hongzhi Mao,Jian Yang,Yitai Qian
Disordered surface of anode materials accompanied by oxygen vacancies , has been developed as an efficient strategy to promote their charge-transfer kinetics and then improve their electrochemical properties . It is rarely explored for cathode materials before. Here, LiTi 2- x Mn x (PO 4- y ) 3 nanoparticles with a disordered surface and oxygen vacancies , are synthesized by a hydrothermal method following with an annealing in Ar/H 2 . Their disordered surface and heteroatom doping by reduced Mn/Ti species, have been supported by HRTEM images, XPS and EDS spectra. After 120 cycles at 0.2 C, these nanoparticles still deliver a capacity of 127 mAh g −1 , much higher than the product without any doping, and that without a disordered surface. Even after 500 cycles, the capacity is still at 101 mAh g −1 for 5 C or at 71 mAh g −1 for 20 C. These results could be attributed to the reduced charge-transfer resistance caused by disordered surface, and the enhanced lithium-diffusion induced by doping.
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CHINESE JOURNAL OF CHEMICAL ENGINEERING
·
2011
·
IF 0.901
Dongshun DENG,Rufa WANG,Lianzhong ZHANG,Yun GE,Jianbing JI
Vapor-liquid equilibrium (VLE) data were measured for ternary system water + ethanol + 1-butyl-3-methylimidazolium acetate ([bmim][OAc]), in a relatively wide range of ionic liquid (IL) mass fractions up to 0.8. Six sets of complete T - x - y data were obtained, in which the mole fraction of ethanol on IL-free basis was fixed separately at 0.1, 0.2, 0.4, 0.6, 0.8, and approximate 0.98. The non-random-two-liquid (NRTL) and electrolyte non-random-two-liquid (eNRTL) equations were used for correlation, showing similar deviations. The ternary VLE was also modeled with the correlation from two data sets, with the mole fractions of ethanol on IL-free basis being 0.1 and approximate 0.98. The VLE data were also reproduced satisfactorily. With the eNRTL model, the root-mean-square deviation for temperature is 0.79 K and that for vapor-phase mole fraction is 0.0094. The calculations are in good agreement with experimental data. The effect of the IL on the VLE behavior of the volatile components is also illustrated.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2020
·
IF 5.162
Yini Liu,Debao Wang,Zhilan Sun,Fang Liu,Lihui Du,Daoying Wang
In this study, antibacterial nanofiber films were prepared by electrospinning gelatin, chitosan, and 3-phenyllactic acid (PLA). The addition of PLA improved the microstructures of the nanofibers, and the nanofiber films (GCP-1 and GCP-2) had uniform and continuous structures with a diameter range of 40‐–70 nm when the PLA concentrations in the polymers were 1% and 2%. Under acidic conditions, chitosan and PLA interacted and formed hydrogen bonds , which decreased the crystallinity of the nanofiber films. The GCP-2 nanofiber film had the best thermal stability , water stability, and water vapor permeability. Compared with the control GCP-0 film, the four nanofiber films with PLA (GCP-1, GCP-2, GCP-3, and GCP-4) had more effective antibacterial effects, and GCP-2 film reduced approximately 4 log CFU/mL of Salmonella enterica Enteritidis and Staphylococcus aureus in 30 min. Results suggested that the GCP-2 nanofiber film mat can be used as an active food packaging.
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JOURNAL OF DISPERSION SCIENCE AND TECHNOLOGY
·
2019
·
IF 1.479
Jialiang Chen,Lirong Fu,Yan Li,Xiaodeng Yang,Beibei Wang,Chunlin Xu,Tianduo Li
To illuminate the interactions in N-[(2-hydroxyl)-propyl-3-trimethyl ammonium] chitosan chloride (HTCC)/sodium carboxymethyl cellulose (CMC) based films, the film-forming solutions were studied by rheology, and HTCC/CMC based films were characterized by Fourier transform infrared spectroscopy, scanning electron microscopy and thermogravimetric analysis. The HTCC/CMC based film-forming solutions with glycerol (polyvinyl alcohol (PVA) and anthocyanin) showed shear-thinning behavior. The apparent viscosity of the HTCC/CMC/glycerol (PVA and anthocyanin) film-forming solutions decreased slower than that of HTCC/CMC film-forming solution, due to the electrostatic interaction between HTCC and CMC, and hydrogen bonding interaction between the two biomacromolecules and glycerol, PVA and anthocyanin, which resulted in the formation of three-dimensional networks. The anthocyanin with rigid molecular structure formed different three-dimensional matrix with HTCC/CMC, resulted in viscosity dominated film-forming solution. The pH affected the electrostatic interaction between HTCC, CMC, and anthocyanin through neutralizing –COO− groups, and temperature showed a synergistic effect on both electrostatic interaction and hydrogen bonding. The inter-molecular interactions resulted in the red-shift of typical absorption peaks, and the increase of initial decomposition temperature and decomposition enthalpy of HTCC/CMC based films. The homogenous and smooth surface, and the compact texture of HTCC/CMC based films confirmed the intermolecular interaction between HTCC, CMC, and PVA (glycerol and anthocyanin).
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JOURNAL OF MOLECULAR LIQUIDS
·
2021
·
IF 6.165
Dan Zhang,Junhui Pan,Deming Gong,Guowen Zhang
Indole-3-butyric acid (IBA) is a broad-spectrum efficient plant growth regulator. It has been widely used in crop production, but may have a potential security risk due to its residual accumulation in agricultural products. Herein, the binding mode between IBA and calf thymus DNA (ctDNA) and influence of IBA on the structure of ctDNA were explored by using spectroscopic methods, viscosity measurement, melting temperature studies coupled with computational approaches. Fluorescence titration results indicated that ctDNA induced IBA fluorescence quenching in a static manner. The measured thermodynamic parameters demonstrated that the structure of IBA-ctDNA complex was primarily stabilized by hydrogen bonds and van der Waals forces. Fluorescence experiments, viscosity analyses and circular dichroism (CD) measurements confirmed that IBA interacted with ctDNA in terms of groove mode with no significant conformational change of ctDNA. Furthermore, molecular docking showed that IBA was preferentially bound to the minor groove of ctDNA rich in A-T bases. Molecular dynamics simulation further revealed IBA and DNA forming a stable complex and IBA could slightly increase the flexibility of ctDNA base pairs. In addition, IBA did not cause significant damage to the structure of DNA. These findings may supply conducive insights into the toxicity mechanisms of IBA at the molecular level.
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JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2020
·Vol. 31
·期 21
·18360-18369
·
IF 2.22
Wang Mengmeng,Tao Yueming,Zhang Dongyun,Sun Guanghan,Feng Ping,Chang Chengkang
Na 3–2 x Mg x V 2 (PO 4 ) 3 /C (0 ≤ x ≤ 0.2) were synthesized by a sol–gel method. According to X-ray diffraction (XRD) Rietveld refinement and energy dispersive spectroscopy (EDS) mapping results, Mg ions were approved to occupy the Na2 (18e) site in Na 3–2 x Mg x V 2 (PO 4 ) 3 /C for the first time. The amount of Mg substitution in Na 3–2 x Mg x V 2 (PO 4 ) 3 /C was optimized. The specific discharge capacities of Na 2.9 Mg 0.05 V 2 (PO 4 ) 3 /C at 10 C, 20 C, and 30 C were 98.9%, 91.5%, and 76.2% of the value obtained at 1 C, respectively. Na 2.9 Mg 0.05 V 2 (PO 4 ) 3 /C exhibited the highest capacity retention of 80.3% with a discharge capacity of 77.3 mAh·g −1 after 1200 cycles at 10 C. Na 2.9 Mg 0.05 V 2 (PO 4 ) 3 /C exhibited superior rate performance, resulting from a high sodium diffusion coefficient ( D Na ) of 3.91 × 10 –12 cm 2 ·s −1 and the excellent electrical conductivity (5.7 × 10 –2 s·cm −1 ). Combining the X-ray photoelectron spectroscopy (XPS) and Electrochemical impedance spectroscopy (EIS) results, the mechanism of Mg substitution was investigated. Since two Na + were replaced by one Mg 2+ , \({\mathrm{V}}_{\text{Na}}^{^{\prime}}\) was produced to maintain valence equilibrium. This phenomenon benefited Na + migration by broadening the diffusion channel in the structure of Na 3 V 2 (PO 4 ) 3 . According to the EPR results, the signal intensity of Na 2.9 Mg 0.05 V 2 (PO 4 ) 3 /C was much stronger than that of Na 3 V 2 (PO 4 ) 2 /C, thus confirming the existence of \({\mathrm{V}}_{\text{Na}}^{\mathrm{^{\prime}}}\) after Mg substitution. When the amount of Mg substitution was further increased to 0.1, the D Na decreased because of the small radius of Mg 2+ , which led to severe lattice distortion and volumetric shrinkage of the unit cell.
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PHYSICAL CHEMISTRY CHEMICAL PHYSICS
·
2024
·Vol. 26
·期 16
·12530-12536
·
IF 2.9
Dingding Lv,Xinlei Chen,Ningjing Jiang,Guanjun Wang,Xiaoqing Zeng,Wei Fang,Weixing Li,Mingfei Zhou
Trifluoroacetylacetone (TFAA) has two enol forms, which can switch to each other via proton transfer. While much attention has been paid to their conformational preferences, the influence of microsolvation on regulating the proton position remains unexplored. Herein, we report the rotational spectra of trifluoroacetylacetone–(water)n (n = 1–3) investigated by chirped pulse Fourier transform microwave spectroscopy in the 2–8 GHz frequency range. Two conformers were identified for both TFAA–H2O and TFAA–(H2O)2, while only one conformer was characterized for TFAA–(H2O)3. The results indicate that water binding on the CH3 side stabilizes the enolF form, whereas water binding on the CF3 side stabilizes the enolH form. The enolF form predominates over the enolH form in these hydrated complexes, which contrasts with the fact that only enolH exists in isolated TFAA. EnolH becomes preferred only when water inserts itself into the intramolecular hydrogen bond. Instanton theory calculations reveal that the proton transfer reaction is dominated by quantum tunneling at low temperatures, leading to the stable existence of only one enol form in each configuration of the hydrated clusters.
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