CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Cuishuang Jiang,Mingyi Zhang,Guojun Dong,Tong Wei,Jing Feng,Yueming Ren,Tianzhu Luan
It is highly desirable but challenging to control nitrate contamination using photocatalytic reduction technology over non-mental catalysts. Herein, hexagonal boron nitride (h-BN), a typical non-metal catalyst, was employed to photocatalytic denitration in water with formic acid (FA) as a hole scavenger. Compared with a mental catalyst TiO 2 and a non-mental catalyst g-C 3 N 4 , h-BN obtained a more effective reduction performance with nitrate conversion of 97.16% and N 2 selectivity of 95.42%. After three cyclic use, it still presented excellent reduction activity and structure stability. In the h-BN system, the initial pH had a significant effect on the nitrate reduction performance because it determined the surface charge property of the catalyst or the dispersibility in water, and the presence of anions slightly decreased the nitrate conversion process since the competitive adsorption of NO 3 – or NO 2 – . Photocatalytic denitration over h-BN was well according with the Extended-Langmuir-Hinshelwood model. By comparing the average stoichiometric ratio of consumed FA and removed NO 3 – (i.e. experiment value) with the theoretical value, it was determined that there were additional electrons involved in the reduction reaction in addition to CO 2 •- radicals, which was also supported by the quenching experiments. Moreover, CO 2 •- radicals were mainly responsible for the conversion of NO 2 – to N 2 . Exposed B atoms on the h-BN edges behaved as the adsorption sites of nitrogen oxide anions. This study provides a proof-of-concept demonstration of non-mental photocatalyst h-BN for more effective management of nitrate contamination.
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Journal of Advanced Ceramics
·
2021
·Vol. 10
·期 6
·1317-1325
·
IF 6.707
Liu Zetan,Zhao Shiqiang,Yang Tian,Zhou Ji
It is possible to improve the machinability of aluminum nitride-hexagonal boron nitride (AlN-h-BN) ceramics while maintaining high strength and high thermal conductivity. The composite ceramics with 0–30 wt% BN as secondary phase were prepared by hot pressed sintering, using yttrium oxide (Y 2 O 3 ) as sintering aid. The phase composition, density, microstructure, mechanical properties, thermal conductivity, and dielectric properties were investigated. The sintering additives were favorable to purify the grain boundaries and improve densification, reacting with oxide impurities on the surface of raw material powder particles. The optimum BN content improved the flexural strength and fracture toughness of composite ceramics with 475 MPa and 4.86 MPa·m 1/2 , respectively. With increasing the amount of BN, the thermal conductivity and hardness of composites gradually decreased, but the minimum value of thermal conductivity was still 85.6 W·m −1 ·K −1 . The relative dielectric constant and dielectric loss tangent of the samples ranged from 6.8 to 8.3 and from 2.4 × 10 −3 to 6.4 × 10 −3 , respectively, in 22–26 GHz.
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Asian Journal of Organic Chemistry
·
2018
·Vol. 7
·期 8
·1626-1634
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IF 2.496
Wen-Jing Pan,Zhong-Xia Wang
Graphical Cut my bonds into pieces : The C−H benzylation of oxazoles and benzoxazoles with benzyl trimethylammonium triflates was performed under mild conditions via Pd-catalyzed C−H/C−N cleavage. The method exhibits a wide scope of substrates and good compatibility of functional groups. The C−H benzylation of oxazoles and benzoxazoles with benzylic ammonium triflates was performed in reasonable to good yields via Pd-catalyzed C−H/C−N cleavage. The method exhibits a wide scope of azoles and benzylic ammonium triflates. A range of functional groups including F, CF 3 , COOEt, C(O)NMe 2 , OMe, OPh, pyridyl and thienyl groups can be tolerated.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2013
·
IF 2.596
Quancai Li,Chunxia Li,Cheng Yang,Chenchang Liu,Guangli Yu,Huashi Guan
Three derivatives of polymannuronic acid (PM) were prepared by chemically polyanionic modification. PM was substituted with phosphate ( OPO 3 2− ), H-phosphonate ( OPO 2 H − ) and sulfate ( OSO 3 − ) groups with the degree of substitution (DS) of 0.41, 1.42 and 1.04, respectively. The structures of all PM derivatives were characterized by FT-IR, 31 P NMR and 13 C NMR spectroscopy . The weight average molecular weight (Mw) was determined by high performance gel permeation chromatography (HPGPC). The antioxidant activities of PM and its derivatives were evaluated in vitro. The results indicated that both phosphate and H-phosphonate groups improved the hydroxyl radical scavenging activity, while sulfate group enhanced the superoxide radical scavenging activity. However, all of the derivatives scavenged DPPH less effectively than PM. The mechanism for how the different anionic substituent groups influenced the antioxidant activities was discussed.
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DYES AND PIGMENTS
·
2015
·
IF 3.966
Bin Shan,Xing Tong,Wei Xiong,Wenzhu Qiu,Bingtao Tang,Rongwen Lu,Wei Ma,Yi Luo,Shufen Zhang
A new kind of reactive dyes containing both monoazo and anthraquinone chromophores was obtained by using 1,4-bis((4-aminophenyl)amino)anthrancene- 9,10-dione as diazo component and 1-amino-8-naphthol-3,6-disulfonicacid (H-acid) derivatives as coupling components. The dyes were characterized by UV–Vis, IR, MS, 1 H NMR and 13 C NMR. The results showed that the maximum absorption wavelengths of the dyes were all about 590 nm, which indicated that they were a kind of blue dyes. 1 H NMR and 13 C NMR results revealed that there were two kinds of tautomerisms in dye structure and a new conjugated system formed between the anthraquinone ring and the phenyl azo linkage. Density functional theory (DFT) calculations also proved the formation of the new larger conjugated system from which the blue colour was generated. The fixations of the dyes on cotton were over 88% and the light fastness reached 5 grade.
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JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2016
·Vol. 99
·期 8
·2615-2624
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IF 2.787
Zhaoju Yu,Pei Zhang,Yao Feng,Shuang Li,Yaxing Pei
We present a template-free synthesis of Fe 3 O 4 /SiOC(H) nanocomposites with in situ formed Fe 3 O 4 nanoparticles with a size of about 50 nm embedded in a nanoporous SiOC(H) matrix obtained via a polymer-derived ceramic route. Firstly, a single-source precursor (SSP) was synthesized by the reaction of allylhydridopolycarbosilane (AHPCS) with Fe-acetylacetonate [Fe(acac) 3 ] at 140°C. The SSP was heat-treated at 170°C to generate Fe 3 O 4 nanocrystals in the cross-linked polymeric matrix. Subsequently, the SSP was pyrolyzed at 600°C–700°C in argon atmosphere to yield porous Fe 3 O 4 /SiOC(H) nanocomposites with the high BET surface area up to 390 m 2 /g, a high micropore surface area of 301 m 2 /g, and a high micropore volume of 0.142 cm 3 /g. The Fe-free SiOC(H) ceramic matrix derived from original AHPCS is nonporous. The in situ formation of Fe 3 O 4 nanoparticles embedded homogeneously within a nanoporous SiOC(H) matrix shows significantly enhanced catalytic degradation of xylene orange in aqueous solution with H 2 O 2 as oxidant as compared with pure commercial Fe 3 O 4 nanoparticles.
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RSC Advances
·
2016
·Vol. 6
·期 107
·105814-105820
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IF 3.289
Zuhuang Wen,Yijuan Long,Lili Yang,Jiangang Hu,Ning Huang,Yuan Cheng,Li Zhao,Huzhi Zheng
Nanoparticles have the great potential to act as drug delivery carriers, and such systems must effectively deliver the drug to the cancer cells, and provide intracellular drug release. In this research, two types of H+-triggered bubble generating nanosystems (BGNS) were developed which were obtained using hollow mesoporous silica nanoparticles loaded with doxorubicin and subsequently treated with bubble generating agents, i.e., sodium bicarbonate (SBC) and ammonium carbonate (AC). These were named BGNS-SBC and BGNS-AC. After internalization by the tumor cells, the H+ reacts with bicarbonate or carbonate to generate carbon dioxide bubbles quickly in an acidic environment of endo/lysosomes, which results in lysosomal membrane permeabilization (LMP). Then, the enhanced LMP induced cancer cell death by an apoptosis-like pathway because of the release of caspase-3 from the lysosome into the cytoplasm. In addition, BGNS-SBC and BGNS-AC possessed remarkable cytotoxicity against MCF-7 cells and efficiently overcame the multidrug resistance (MDR) of MCF-7/adriamycin cells. Therefore, these bubble generating nanosystems could be a promising nanocarrier for the treatment of tumors.
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Foods
·
2024
·Vol. 13
·期 17
·2652
·
IF 4.7
Na Li,Xiao Wu,Qin Yin,Zeng Dong,Lele Zheng,Yihui Qian,Yulu Sun,Ziping Chen,Kefeng Zhai
The extraction of total flavonoids fromHylotelephium spectabile(Boreau) H. Ohba (H. spectabile) leaves was studied through the use of a double enzyme-assisted ultrasonic method, and the extraction process was optimized using the Box–Behnken design. Eight different macroporous resins were screened for purification in single-factorial experiments, and the flavonoid compounds in the extract ofH. spectabileleaves were identified using HPLC-MS. Through the evaluation of the total reducing capacity and capacity for reducing 1,1-diphenyl-2-trinitrophenylhydrazine (DPPH), hydroxyl radicals (·OH), and 2,2’-biazobis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS), the in vitro antioxidant activities of the crude extracts of the total flavonoids and purified total flavonoids ofH. spectabileleaves were investigated. The results showed that the most efficient conditions for flavonoid extraction were an ultrasonic extraction time of 60 min, an ethanol concentration of 35%, a liquid-to-material ratio of 20:1 mL/g, and an amount of enzyme (cellulose/pectinase = 1:1) of 1.5%, formingH. spectabilepowder. Under these conditions, the total flavonoid extraction rate in theH. spectabileleaf extract was 4.22%. AB-8 resin showed superior performance in terms of purification, and the optimal adsorption and desorption times were 1.5 h and 3 h, respectively. The recommended parameters for purification included a liquid volume of 5.5 BV, a flow rate of 1.2 BV/min, a pH of 5, and a concentration of 0.8 mg/mL. The observed order for reducing capacity was ascorbic acid (VC) > rutin > purified total flavonoids > crude extract of total flavonoids. The purified total flavonoid extract fromH. spectabileshowed a good scavenging ability against DPPH, ·OH, and ABTS·+, suggesting strong antioxidant activity. Therefore, this study can serve as technical support and reference data for the further development and utilization ofH. spectabileresources.
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IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT
·
2024
·
IF 5.6
Qi Wang,Hao-Yue Wang,Nuerguli Kari
Rapid and incredibly sensitive analyte detection is crucial in a variety of settings, including medical diagnostics. However, conventional surface plasmon resonance (SPR) sensors cannot effectively solve the issue of low sensitivity when assaying trace analytes. In this work, the rare Earth oxide Lu2O3 is first introduced to modify fiber optic SPR sensor. By utilizing the inherent advantages of Lu2O3, including high dielectric constant, high breakdown field strength, and high photoelectric conversion efficiency, the electric field around the sensor is effectively increased and high sensitivity detection is achieved. Experimental results show sensitivity of the sensor modified with Lu2O3 nanomaterial reaches 12133.78 nm/RIU in the interval of 1.3614–1.3756. The hexagonal boron nitride (h-BN) is subsequently introduced to further enhance electric field using the charge transfer mechanism. The sensitivity reaches 15065.92 nm/RIU, 3.96 times better than conventional U-shaped fiber SPR sensors. The sensor is compact designed with high sensitivity. There is significant potential for improving the sensitivity aspect of analyte detection.
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SOLAR ENERGY MATERIALS AND SOLAR CELLS
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2024
·
IF 6.3
Ziqiang Cheng,Gang Xu,Yong Liu,Gaorong Han
Benefitting from large-sized ion tunnels and stable crystalline structures, hexagonal WO 3 (h-WO 3 ) is a promising electrochromic (EC) material. However, long reaction times and highly controlled reaction conditions for preparation hinder the practical application. Here, a novel method with a simple process and moderate condition, named topotactic layer-to-tunnel crystallization (TLTC), to prepare h-WO 3 films is reported. The hexagonal tunnel structure is transformed from a layered structure by annealing, assisted by the structure director. The ACTEM with atomic resolution reveals the position of the structure director in the crystal lattice, which is left in the hexagonal tunnel. The mechanism of TLTC has been studied by the characterization of samples at different formation stages, and the key is the structure director, which maintains the hexagonal tunnel by steric effect. The prepared h-WO 3 film exhibits significant optical modulation (65.8 % at 633 nm and 72.8 % at 1200 nm) and outstanding cyclic stability (98.1 % of initial optical modulation remained over 600 cycles). The TLTC method is based on the structure transition to construct large tunnels in lattice, providing a new technical route to prepare h-WO 3 and showing great potential for EC materials manufacturing.
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INORGANIC CHEMISTRY COMMUNICATIONS
·
2024
·
IF 4.4
Han Song,Jiasheng Fan,Shengkai Liu,Boyu Chen,Jin Huang,Yujie Fu,Zhiguo Liu
In this study, we synthesized DOX-loaded H-ZIF-8@CaCO 3 -PEG nanocarrier, which combined with calcium overload and photothermal therapy (PTT) for synergistic therapy. The nanocarrier comprised a PEG modified calcium carbonate (CaCO 3 ) shell and a hollow imidazolate zeolite skeleton (H-ZIF-8) core, in which the chemotherapy drug doxorubicin hydrochloride (DOX) and photosensitizer indocyanine green (ICG) were simultaneously co-loaded. In vitro cellular experiments revealed that the lethality of DOX&ICG@H-ZIF-8@CaCO 3 -PEG against tumor cells was significantly higher than that of the single chemotherapy owing to the combination with chemotherapy and photothermal therapy as well as calcium overloading. This drug-loaded nanocarrier exhibits notable characteristics such as exceptional stability, elevated drug loading capacity and efficient release of the loaded drug, which provides a promising perspective for efficient synergistic therapy.
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Nature Communications
·
2025
·Vol. 16
·期 1
·1-12
·
IF 15.7
Hu Yaqi,Liu Runze,Lu Kaiyun,Wu Daoning,Gao Pan,Hou Guangjin,Zhang Hongbo,Dai Weili
Hydrated hydronium ions formed in the pores/cages of zeolite catalysts are suggested as the active species that could impact the adsorption of reactant, the stability of intermediates or transition states, and the reaction mechanism in the aqueous phase alcohol dehydration. Nevertheless, under a typical vapor phase reaction condition, the relevant situation is still debatable. Herein, the promotion of water on cyclohexanol (CyOH) adsorption and dehydration under a vapor phase condition was clarified by in situ 1 H MAS NMR, 2D 1 H DQ MAS NMR and 2D 1 H- 27 Al HMQC NMR spectroscopy, systematic kinetic studies, isotope tracing and thermodynamic measurements. The water promoting effects were ascribed to water facilitating the formation of H 3 O + cluster (H 3 O + (H 2 O) n-1 ), and per Brønsted acid site (BAS) could be saturated by about 5 water at ambient temperature. The CyOH dehydration pathway was found to be highly dependent on the water concentrations, and a dimer reaction route with the C-H bond rupture as the kinetically relevant step (KRS) was verified as the main reaction pathway at high water concentrations. All these findings provide the deep insights into how water regulating the zeolite catalyzed dehydration reaction at a molecular level.
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