Journal of Advanced Ceramics
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2021
·Vol. 10
·期 6
·1291-1298
·
IF 6.707
Huang Jiaxuan,Wan Hujie,Li Mian,Zhang Yiming,Zhu Jianfeng,Li Xuelin,Shui Wenchao,Li Yao,Fan Xiaomeng,Wen Qiye,Xiao Xu,Huang Qing
Electromagnetic interference (EMI) shielding materials have received considerable attention in recent years. The EMI shielding effectiveness (SE) of materials depends on not only their composition but also their microstructures. Among various microstructure prototypes, porous structures provide the advantages of low density and high terahertz wave absorption. In this study, by using carbonised wood (CW) as a template, 1-mm-thick MAX@CW composites (Ti 2 AlC@CW, V 2 AlC@CW, and Cr 2 AlC@CW) with a porous structure were fabricated through the molten salt method. The MAX@CW composites led to the formation of a conductive network and multilayer interface, which resulted in improved EMI SE. The average EMI SE values of the three MAX@CW composites were > 45 dB in the frequency of 0.6–1.6 THz. Among the composites, V 2 AlC@CW exhibited the highest average EMI SE of 55 dB.
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JOURNAL OF ELECTRONIC MATERIALS
·
2021
·Vol. 50
·期 11
·6414-6425
·
IF 1.938
Fan Wentao,Du Yongqiang,Zhou Jianjun,Ma Xueqing,Liu Yingliang,Xu Shengang,Cao Shaokui
The introduction of polymer additives provides a simple effective method to modify perovskite grain boundaries to improve power conversion efficiency (PCE) and stability of perovskite solar cells (PSCs). In this work, the high-quality methylammonium lead triiodide (MAPbI 3 ) perovskite film is prepared by adding the protonated polyamide-amine dendrimer (NH 3 + -PAMAM) to the perovskite precursor solution to regulate the crystalline growth process. The cross-linked perovskite grain structure induced by dendritic NH 3 + -functionalized PAMAM macromolecules results in the formation of compact and pinhole-free perovskite film owing to the suppression of perovskite gain boundaries. Finally, the unsealed NH 3 + -PAMAM modified PSC device achieves the highest PCE value of 16.03%, representing an increase of 48% compared with the control PSC device. Also, the unencapsulated NH 3 + -PAMAM-modified PSC device retained 75% of initial PCE value after being exposed to an ambient environment for 20 days, which is obviously higher than 10% for the control device. The improvements of perovskite morphology and photovoltaic performance are attributed to the modification of NH 3 + -PAMAM dendrimers. Graphic abstract
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Biomass Conversion and Biorefinery
·
2021
·Vol. 13
·期 12
·10701-10710
·
IF 4.987
Zeng Qin,Du Zhenyu,Luo Ligang
In this study, different bimetallic (Ru, Pd, and Pt) catalysts over a variety of supports (activity carbon, γ-Al 2 O 3 , TiO 2 , HZSM-5) were employed to improve the kraft lignin depolymerization process using isopropanol as in situ hydrogen source. The effect of catalysts was firstly investigated, which suggested that 1wt%Ru-1wt% Pd/HZSM-5 promoted the hydrogenolysis and hydrodeoxygenation effect on conversion of kraft lignin (95.86 wt%) and the selectivity of aliphatic alcohol (26.92 wt%) and hydrocarbon monomers (35.73 wt%), respectively. The effect of temperature and reaction time were also discussed, which indicated that the high temperature (250 to 310 °C) promoted the hydrogenolysis process; while the temperature is higher than 310 °C, the repolymerization process was appeared, leading to the decreasing yield of total monomers. For the influence of reaction time, it was noted that the optimal reaction time to acquired high yield and selectivity of aliphatic alcohol and hydrocarbon monomer was 120 min. It was also conducted FTIR and 2D HSQC NMR analysis to understand the effective depolymerization of the major linkages with attacked by the Ru-Pd/HZSM-5 catalyst, which was corresponding with the results with GC–MS. Graphical abstract
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IONICS
·
2021
·Vol. 27
·期 11
·4849-4857
·
IF 2.817
Hussain Saddam,Li Yangping,Mustehsin Ali,Ali Akbar,Thebo Khalid Hussain,Ali Zeeshan,Hussain Sabir
In this work, we prepare samarium-doped ceria (SDC) nanocomposite electrolytes by the co-precipitation method with different ZnO:SDC weight ratios for solid oxide fuel cell application. The physicochemical characterization of the nanocomposite electrolytes is carried out by X-ray diffraction (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) techniques. Electrochemical impedance spectroscopy is performed to measure the electrical properties of the electrolytes, and the results show that the optimum composition of ZnO ( x = 0.2) nanocomposite demonstrates a better ionic conductivity ~ 0.1–0.7 S/cm at 350–700 °C. The fuel cell performance of the ZnO/SDC nanocomposite electrolytes is measured with hydrogen as the fuel. The as-synthesized nanocomposite material with ZnO ( x = 0.2) also exhibits a power density of 804 mW/cm 2 along with a maximum open-circuit voltage (OCV) of 1.10 V at 700 °C.
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CLAYS AND CLAY MINERALS
·
2021
·Vol. 69
·期 4
·434-442
·
IF 1.609
Zhang Mingzhu,Sun Shiyong,Lv Rui,Golubev Yevgeny Aleksandrovich,Wang Ke,Dong Faqin,Kotova Olga Borisovna,Kotova Elena Leonidovna
Lipase is an industrial enzyme, the catalytic efficiency of which is restricted by various environmental factors. To improve this efficiency, immobilization technology has been utilized in the past to improve the stability of lipase in harsh conditions. Immobilization technology can be divided into physical methods and chemical methods. Some unsolved problems remain in current immobilization technology. The interaction between enzyme and immobilization support is weak and reversible during physical adsorption, resulting in poor stability of the immobilized enzyme and the contamination of substrate solution by leached enzymes. In chemical methods, enzyme-active sites might be inactivated due to the chemical reactions between enzyme molecules and support, resulting in a decrease in the enzymes’ catalytic activity (Liu et al., 2018a ). The objective of the current study was to construct a nanostructured lipase via Mg-amino-clay as a carrier and improve the catalytic activity and stability of lipase by immobilization. Lipase produced by Aspergillus oryzae was immobilized on aminopropyl functionalized magnesium phyllosilicate (a 2:1 trioctahedral talc-like silicate Mg-amino-clay) via a 1-(3-Dimethylaminopropyl)-3-ethyl-carbodiimide hydrochloride (EDC) coupling agent. The physical and chemical properties of the Mg-amino-clay and Mg-amino-clay-based nanostructured biocatalyst (Mg-clay-lipase) were characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, and scanning electron microscopy. Optimal immobilization conditions were determined by taking into account the following variables: amount of initial lipase, EDC concentration, and reaction time. The results revealed that the optimum temperature, pH, and thermal stability of Mg-clay-lipase were greater than equivalent values for free lipase under optimal conditions (described below – Process for Immobilization of Lipase on Mg-amino-clay ). The Michaelis-Menten constant (K m ) values were 5.25 mM and 7.42 mM while the maximum reaction rates ( v max ) were 30.58 mM/(L·min) and 55.87 mM/(L·min) for free lipase and Mg-clay-lipase, respectively. The present study provided a new nanostructured biocatalyst and demonstrated that the enzyme activity and stability of Mg-clay-lipase were superior to those of free lipase due to the mechanism of 'interface activation'.
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Reaction Kinetics Mechanisms and Catalysis
·
2021
·Vol. 134
·期 1
·243-257
·
IF 2.081
Zhang Wenfei,Zhou Qulan,Qi Ji,Li Na
Cu 2 O films were prepared using an improved solution immersion method, whereas ZnO/Cu 2 O films were prepared using an electrodeposition method. Then, the pure Cu 2 O film electrodes and ZnO/Cu 2 O film electrodes were used to reduce CO 2 to CH 3 OH. The crystal structure, morphology, particle size, and specific surface area of pure Cu 2 O films prepared under different immersion times and ZnO/Cu 2 O films prepared under different deposition times and Zn 2+ concentrations were analyzed using X-ray diffraction, scanning electron microscopy, and Brunauer–Emmett–Teller analysis. The electrolytic activity of the pure Cu 2 O film electrodes and ZnO/Cu 2 O film electrodes were studied. Under the same reaction conditions, the ZnO/Cu 2 O film electrode with the Zn 2+ concentration of 0.05 M and the deposition time of 30 min had the highest total CH 3 OH yield of 315.656 μmol/cm 2 and the fastest formation rate of 52.609 μmol/(cm 2 h), and its faradaic efficiency was 45%, which was remarkably higher than that of pure Cu 2 O film electrodes under the same reaction conditions. This study highlighted that ZnO nanoparticles had a very good promotion of electrolytic CO 2 reduction on Cu 2 O film.
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JOURNAL OF NANOPARTICLE RESEARCH
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2021
·Vol. 24
·期 1
·1-12
·
IF 2.253
Gong Zhenhu,Wei Zongnan,Liu Yizhang,Xiao Lufei
A ratiometric fluorescent deoxyribonucleic acid (DNA) probe was synthesized using the photoinduced electron transfer (PET) mechanism, involving the interactions between different fluorescent components and electron acceptors. Double-emission carboxyl-functionalized semiconducting polymer dots with an average diameter of 26.7 nm were synthesized using the nanoprecipitation method and applied as a fluorophore, and methylene blue (MB) was used as the electron acceptor. PET between different polymer dots components and MB can achieve ratiometric modulation of the overall fluorescence in the system. The addition of DNA restores the fluorescence intensity, because the strong interactions between DNA and MB result in MB being separated from the polymer dots. Under optimized experimental conditions, system fluorescence was restored to its maximum when the concentration of DNA reached 200 nM; the linear range was 0.006–200 nM ( R 2 = 0.995). This probe was reasonably free from interference, showing a good response to DNA, with strong application data from actual samples.
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ANALYTICAL AND BIOANALYTICAL CHEMISTRY
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2021
·Vol. 414
·期 3
·1389-1402
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IF 4.157
Lv Xiaoyi,Bi Mengmeng,Xu Xiaoyun,Li Yanping,Geng Chao,Cui Bo,Fang Yishan
Aggregation-induced electrochemiluminescence reagent, a distyrylbenzene derivative with donor–acceptor conjugated nanosheet structure, namely TPAPCN, was used as a trace label and modified on the electrode through the formation of classical sandwich complex of antibody-antigen–antibody in this work. In aggregate state, TPAPCN with twisted structure was limited in nanometer space through intermolecular π − π stacking interactions, which not only restricts the intramolecular motions but also combines a large number of singlet excitons to greatly trigger electrochemiluminescence (ECL). The ECL signal of this system enhanced with more captured cytokeratin 19 fragment 21–1 (CYFRA21-1) on the modified electrode. Three-dimensional graphene/platinum nanoparticles with large specific surface, and excellent electroconductivity and biocompatibility were prepared and acted as excellent carriers for thionine handling (3D-GN/PtNPs/Th), which was employed for improving the loading of antibodies and generating internal electrochemical signal. Consequently, a novel ratiometric sandwich immunosensor for CYFRA21-1 detection was fabricated based on TPAPCN and 3D-GN/PtNPs/Th, that is, a rapid and reliable detection was achieved through the ratio between ECL and electrochemical signals. The prepared sensor performed good linearity in the range of 50 fg/mL to 1 ng/mL with a detection limit as low as 16 fg/mL. Moreover, the detection results revealed well in the analysis of human serum samples, demonstrating a significant application for clinical monitoring and biomolecules detection. Graphical abstract
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International Journal of Minerals Metallurgy and Materials
·
2021
·Vol. 28
·期 10
·1636-1646
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IF 2.232
Wei Tao,Zhang Zao-hong,Zhang Qi,Lu Jia-hao,Xiong Qi-ming,Wang Feng-yue,Zhou Xin-ping,Zhao Wen-jia,Qiu Xiang-yun
Anion-immobilized solid composite electrolytes (SCEs) are important to restrain the propagation of lithium dendrites for all solid-state lithium metal batteries (ASSLMBs). Herein, a novel SCEs based on metal-organic frameworks (MOFs, UiO-66-NH 2 ) and superacid ZrO 2 (S-ZrO 2 ) fillers are proposed, and the samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS), thermo-gravimetric analyzer (TGA) and some other electrochemical measurements. The -NH 2 groups of UiO-66-NH 2 combines with F atoms of poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) chains by hydrogen bonds, leading to a high electrochemical stability window of 5 V. Owing to the incorporation of UiO-66-NH 2 and S-ZrO 2 in PVDF-HFP polymer, the open metal sites of MOFs and acid surfaces of S-ZrO 2 can immobilize anions by strong Lewis acid-base interaction, which enhances the effect of immobilization anions, achieving a high Li-ion transference number ( t + ) of 0.72, and acquiring a high ionic conductivity of 1.05×10 −4 S·cm −1 at 60°C. The symmetrical Li/Li cells with the anion-immobilized SCEs may steadily operate for over 600 h at 0.05 mA·cm −2 without the short-circuit occurring. Besides, the solid composite Li/LiFePO 4 (LFP) cell with the anion-immobilized SCEs shows a superior discharge specific capacity of 158 mAh·g −1 at 0.2 C. The results illustrate that the anion-immobilized SCEs are one of the most promising choices to optimize the performances of ASSLMBs.
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Communications Biology
·
2021
·Vol. 4
·期 1
·1-12
·
IF 6.268
Liu Yuan,Tong Ziwen,Shi Jingru,Jia Yuqian,Deng Tian,Wang Zhiqiang
Antimicrobial resistance has been a growing concern that gradually undermines our tradition treatment regimens. The fact that few antibacterial drugs with new scaffolds or targets have been approved in the past two decades aggravates this crisis. Repurposing drugs as potent antibiotic adjuvants offers a cost-effective strategy to mitigate the development of resistance and tackle the increasing infections by multidrug-resistant (MDR) bacteria. Herein, we found that benzydamine, a widely used non‐steroidal anti‐inflammatory drug in clinic, remarkably potentiated broad-spectrum antibiotic-tetracyclines activity against a panel of clinically important pathogens, including MRSA, VRE, MCRPEC and tet (X)-positive Gram-negative bacteria. Mechanistic studies showed that benzydamine dissipated membrane potential ( ▵ Ψ) in both Gram-positive and Gram-negative bacteria, which in turn upregulated the transmembrane proton gradient ( ▵ pH) and promoted the uptake of tetracyclines. Additionally, benzydamine exacerbated the oxidative stress by triggering the production of ROS and suppressing GAD system-mediated oxidative defensive. This mode of action explains the great bactericidal activity of the doxycycline-benzydamine combination against different metabolic states of bacteria involve persister cells. As a proof-of-concept, the in vivo efficacy of this drug combination was evidenced in multiple animal infection models. These findings indicate that benzydamine is a potential tetracyclines adjuvant to address life-threatening infections by MDR bacteria.
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JOURNAL OF POLYMER RESEARCH
·
2021
·Vol. 28
·期 11
·1-10
·
IF 3.097
Jing Xianwu,Huang Chenzhi,Fu Ziyi
The aim of the present work is to prepare polymeric materials and to be used as drag reducer. In this paper, a new type of drag reducer was synthesized with polymeric materials. Technically, N, N-dimethyl-N-hexadecyl allylammonium bromide (DHAB) was synthesized with 3-bromopropene and N, N-dimethylcetyl tertiary amine, and then cationic hydrophobically associating polyacrylamide P(AM-DHAB), the desired drag reducer, was synthesized. The chemical structures of the products were confirmed by IR and NMR. The molecular weight of the drag reducer was found to be 2.66 × 10 6 g/mol as measured by laser light scattering method. In fresh water, when the concentration of drag reducer is 0.03%, the highest drag reduction rate is reached up to 73.05%. However, when the concentration of drag reducer is further increased, the viscosity is increased and drag reduction rate is decreased; indicating high viscosity has a significant negative effect on drag reduction rate. While in brine, with a viscosity obviously lower than that in fresh water, the drag reduction rate was slightly lower than 70% when the concentration of drag reducer was 0.03%; increasing the concentration of P(AM-DHAB) did not lead to a significant increase in viscosity, instead, it caused the drag reduction rate to be higher than 70%. Therefore, low viscosity facilitates drag reduction performance. Potassium persulfate makes the viscosity of slick water decrease sharply, which helps promote the polymer degradation and thus prevent polymer damage to the reservoir. Scanning electron microscope (SEM) showed that the drag reducer featured an obvious network structure in fresh water before gel breaking, and that there was almost no network structure but a small number of crystallites after gel breaks. In contrast, in brine, no matter before and after gel breaking, only salt crystals were cleanly seen under electron microscope due to high concentration of salt.
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MICROCHIMICA ACTA
·
2021
·Vol. 188
·期 11
·1-9
·
IF 5.833
Chen Shuqin,Huang Mengna,Huang Mianli,Feng Liang
A strategy based on CsPbBr 3 quantum dots (QDs) is described for the determination of ziram pesticide. A facile and inert gas-free method was used for the synthesis of CsPbBr 3 QDs. The obtained CsPbBr 3 QDs displayed turn-off fluorescence behavior for ziram. The fluorescence intensity of the CsPbBr 3 QDs ( E x / E m = 365/516 nm) was inversely proportional to the concentration of ziram (0.10 to 50.0 ppm) with a detection limit of 0.086 ppm. Notably, satisfactory recoveries (100 ± 0.25 to 107 ± 5.72%) were obtained in spiked fruit samples, which demonstrated that this method is capable of detecting ziram in real samples. In addition, the mechanism for the detection of ziram was investigated in detail. According to the results, this mechanism can be tentatively explained by fluorescence quenching originating from the increased surface defects and the structural changes of the CsPbBr 3 QDs. The detection ability of this strategy shows promising applicability in food safety. Graphical abstract
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高影响因子
危险品化学品经营许可证（带存储）