RSC Advances
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2020
·Vol. 10
·期 71
·43599-43606
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IF 3.119
Xiaomeng Dou,Wenzhi Li,Chaofeng Zhu,Xiao Jiang,Hou-min Chang,Hasan Jameel
Efficient cleavage of aryl–ether linkages is a key strategy for generating aromatic chemicals and fuels from lignin. Currently, a popular method to depolymerize native/technical lignin employs a combination of Lewis acid and hydrogenation metal. However, a clear mechanistic understanding of the process is lacking. Thus, a more thorough understanding of the mechanism of lignin depolymerization in this system is essential. Herein, we propose a detailed mechanistic study conducted with lignin model compounds (LMC) via a synergistic Co–Zn/Off-Al H-beta catalyst that mirrors the hydrogenolysis process of lignin. The results suggest that the main reaction paths for the phenolic dimers exhibiting α-O-4 and β-O-4 ether linkages are the cleavage of aryl–ether linkages. Particularly, the conversion was readily completed using a Co–Zn/Off-Al H-beta catalyst, but 40% of α-O-4 was converted and β-O-4 did not react in the absence of a catalyst under the same conditions. In addition, it was found that the presence of hydroxyl groups on the side chain, commonly found in native lignin, greatly promotes the cleavage of aryl–ether linkages activated by Zn Lewis acid, which was attributed to the adsorption between Zn and the hydroxyl group. Followed by the cobalt catalyzed hydrogenation reaction, the phenolic dimers are degraded into monomers that maintain aromaticity.
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JOURNAL OF RADIOANALYTICAL AND NUCLEAR CHEMISTRY
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2020
·Vol. 326
·期 3
·1867-1877
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IF 1.137
Xie Xiaoqing,Wang Yanfei,Xiong Zeng,Li Hongzheng,Yao Chen
Poly(cyclotriphosphazene- co -polyethyleneimine) microspheres with the solid structure were synthesized by precipitation polymerization method for the separation of highly toxic uranium(VI). The structure and morphology of the prepared microspheres were analyzed via FTIR, SEM–EDS, TEM and BET. The optimal adsorption conditions were also investigated, and the maximum adsorption capacity was 274.2 mg g −1 . The experimental results showed that the adsorption kinetics conformed to the pseudo-second-order kinetics and was in good agreement with the Langmuir adsorption isotherm model. Removal of uranium(VI) ions was achieved by the complexation between the amino groups on the adsorbent and uranyl ions.
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JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
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2020
·Vol. 32
·期 1
·1061-1072
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IF 2.22
Wang Yan,Di Xiaochuang,Lu Zhao
Lightweight absorbers with strong broadband microwave absorption are highly desired in military and civil fields. In this work, a 3D interpenetrating network formed from a Co@C@ MWCNTs composite was synthesized via a combined wet chemical and pyrolysis route. Because of strengthening interfacial polarization, suitable impedance matching and synergistic effects, the Co@C@MWCNTs hierarchical composite exhibited outstanding microwave absorption properties. An optimal reflection loss reached − 55.7 dB at 8.7 GHz and its effective bandwidth ( R L < − 10 dB) achieved 4 GHz (7.4–11.4 GHz) at an absorber thickness of 3 mm with a low filler content of 10 wt%. Furthermore, an effective bandwidth of 12.4 GHz (4.5–16.9 GHz) was obtained by varying the thickness from 2 to 4.5 mm. The superior microwave absorption performance originated from the enhanced interfacial polarization, multiple reflections, conductive network, synergistic effects and an improved impedance matching between Co–C and MWCNTs. This work provides a strategy to rationally design novel lightweight absorbers with strong microwave absorption.
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KOREAN JOURNAL OF CHEMICAL ENGINEERING
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2020
·Vol. 37
·期 12
·2143-2151
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IF 2.69
Shi Guangyu,Wang Yuanhao,Cao Yafeng,Cai Weijie,Tan Fengzhi
A Ni/Ce 0.8 Zr 0.2 O 2 catalyst (NiCeZr-N) was synthesized by a facile co-nanocasting technique for syngas production from ethanol dry reforming. In addition, a series of characterization techniques, such as transmission electron microscopy (TEM), X-ray diffraction (XRD), inductive coupled plasma Emission Spectrometer (ICP), X-ray photoelectron spectroscopy (XPS), Raman and hydrogen temperature programmed reduction (H 2 -TPR) were selected to evaluate the physicochemical features of the as-prepared catalysts. Indeed, the results indicated that NiCeZr-N catalyst prepared by co-nanocasting method had a smaller particle size (<5 nm), relatively higher specific surface area (39 m 2 /g) and stronger metal-support interaction in comparison with another model catalyst obtained from conventional co-precipitation method (NiCeZr-P). Expectedly, these positive factors enabled NiCeZr-N catalyst to exhibit better activity and stability. Typically, ethanol is completely converted by using NiCeZr-N as catalyst and heating to 700 °C, and CO 2 conversion was as high as 65.3%. Interestingly, H 2 /CO was close to 1.1 at 650 °C, which could be used as feedstocks of Fischer-Tropsch process. Particularly, no obvious fluctuation of ethanol conversion and the product selectivity was observed during 40 h time-on-stream stability test.
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Expert Opinion on Drug Delivery
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2020
·
IF 4.838
Pu Guo,Chao Pi,Shijie Zhao,Shaozhi Fu,Hongru Yang,Xiaoli Zheng,Xiaomei Zhang,Ling Zhao,Yumeng Wei
Background A novel nanoemulsion (CU/FU-LN) was developed as an oral 5-fluorouracil and curcumin co-delivery system for synergistic efficacy against liver cancer.Methods MTT assay, confocal laser scanning microscope, and H&E staining were utilized to establish the efficacy and safety of CU/FU-LN.Results The AUC(0-t) of CU/FU-LN was 8.85-fold and 8.59-fold greater than those of CU and FU, respectively. The IC50 of CU/FU-LN was 4.6-fold and 4.9-fold lower than those of FU and CU in HepG2 cells, respectively. In vivo anti-tumor trials, the tumor inhibition rate was significantly elevated by CU/FU-LN (49.29%), compared 24.84% and 4.72% for FU and CU, respectively. Ki-67 immunohistochemical analysis revealed that CU/FU-LN had an obvious anti-proliferation effect. The IC50 of CU/FU-LN in L02 cells was 1.51-fold and 2.60-fold higher than those of CU and FU, respectively. Certain vital organs in the mice of the CU/FU-LN group showed markedly fewer lesions than those of the CU, FU, and CU+FU groups. The CU/FU-LN treatment caused no significant change in mouse body weight relative to the control group (P > 0.05). Conclusions We successfully prepared a promising co-delivery platform for the synergistic treatment of liver cancer and it has a comparatively enhanced efficacy and mitigated toxicity.
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Journal of Materials Chemistry B
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2021
·Vol. 9
·期 33
·6691-6702
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IF 6.331
Xiangji Liu,Yihang Ma,Minjiang Chen,Jiansong Ji,Yuhang Zhu,Qingsan Zhu,Min Guo,Peibiao Zhang
Hydroxyapatite (HA) is the most commonly used orthopedic implant material. In recent years, the emergence of cationic doped hydroxyapatite has revealed more possibilities for the biological application of HA. Conventional HA does not promote new bone formation because of its poor osteoinductive activity, and has a similar density to that of bone, leading to difficulty in distinguishing both via imaging. Magnesium ions are useful for regulating the cellular behavior and promoting bone regeneration. Ba ion related compounds, such as BaSO4, have a strong X-ray shielding effect. In this study, Ba/Mg@HA was synthesized to prepare Ba/Mg@HA/PLGA composites, and we aimed to investigate if Ba/Mg@HA/PLGA composites enhanced bone repair on osteoblasts and tibial defects, as well as the X-ray and CT imaging ability of bone implants in rats. The in vitro experimental results showed that the Ba/Mg@HA/PLGA composites significantly improved the attachment and osteogenic differentiation of MC3T3-E1 cells. These include the promotion of mineral deposition, enhancement of alkaline phosphatase activity, upregulation of OCN and COL-1 gene expression, and increase in COL-1 and OCN protein expression in a time- and concentration-dependent manner. The in vivo experimental results showed that the Ba/Mg@HA/PLGA composites significantly increased the rate of bone defect healing and the expression of BMP-2 and COL-1 in the bones of rats. X-ray and CT imaging results showed that the Ba/Mg@HA/PLGA composites enhanced the X-ray imaging ability. These findings indicate that the Ba/Mg@HA/PLGA composites can effectively promote bone formation and improve the X-ray and CT imaging abilities to a certain extent.
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SEPARATION AND PURIFICATION TECHNOLOGY
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2020
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IF 5.774
Dandan Cao,Qingyao Wang,Yue Wu,Shuxu Zhu,Yao Jia,Renliang Wang
Bi/Bi 2 MoO 6 /TiO 2 NTs photocatalysts were synthesized on the basis of TiO 2 NTs by a solvothermal method using glucose as the reducing agent. The removal of organic dyes such as RhB and MB and heavy metal ions like Cr(VI) were used to simulate industrial wastewater for the photocatalytic activity assessment of Bi/Bi 2 MoO 6 /TiO 2 NTs. Na 2 S/Na 2 SO 3 solution was used as sacrificial agent to study the photocatalytic hydrogen generation performance of samples. The results showed that Bi 3+ was successfully reduced to metal Bi and deposited on the surface of Bi 2 MoO 6 . The removal efficiencies of RhB, MB and Cr(VI) reached 73.21%, 92.98% and 70.54%, respectively, which confirmed the excellent photocatalytic activity of samples. The photocatalytic hydrogen production performance of the sample was also remarkable and the hydrogen generation rate reached 173.41 μmol·h −1 ·cm −2 . The active species and photocatalytic mechanism of pollutant degradation and hydrogen generation were proposed based on the photoelectrochemical data. The excellent photocatalytic performances of Bi/Bi 2 MoO 6 /TiO 2 NTs will exhibit prospective guidance for the preparation and photocatalytic water splitting of bismuth-based photocatalysts.
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COLLOID AND POLYMER SCIENCE
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2020
·Vol. 298
·期 6
·629-636
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IF 1.536
Yang Xu,Li Wenbo,Sun Zhaojie,Yang Chunhui,Tang Dongyan
In this work, pH/temperature dual-sensitive polymers of P(NVCL-co-MAA) with the increased low critical solution temperature (LCST) values of about 37 °C that differed from that of ~ 32 °C of pure poly(N-vinyl caprolactam) (PNVCL) were synthesized via radical polymerization. Then the nanofibers of P(NVCL-co-MAA) and its cospinned nanofibers with nifedipine (NIF) as drug model were fabricated by electrospinning method. Structures and the interactions within the components were detected by FT-IR, NMR, and XPS methods. The dual-responsive properties and the controlling release of the drug were investigated by water contact angle tests and in vitro drug release tested by UV-vis spectrophotometer. SEM was conducted to demonstrate the morphology of the nanofibers and the obvious improved stabilized morphology of the modified system within the aqueous media. The maintained morphology within the media and the obvious elongated releasing period of over 150 min at 37 °C and with pH of 1.99 both proved the promising prospects of the fabricated nanofibers as excellent carrier in drug delivery system.
Graphical abstract
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JOURNAL OF HAZARDOUS MATERIALS
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2020
·
IF 9.038
Jingju Cai,Minghua Zhou,Xin Xu,Xuedong Du
Anode materials are crucial to anodic oxidation for wastewater treatment. In this regard, stable boron and cobalt co-doped TiO 2 nanotube (B, Co-TNT) was prepared for the first time, and its lifetime was found increased significantly while electrocatalytic activity decreased with the increase of Co(NO 3 ) 2 in preparation from 1 to 10 mM. Characterized by scanning electron microscope (SEM), X-Ray Diffraction (XRD) and X-ray Photo-electronic Spectroscopy (XPS), B and Co content were optimized and successfully doped on TNT, which was more smooth without ripple with Co content of 0.038 mg/cm 2 in a valence of +2, and B atomic content of 2.17 at.% in form of Ti-B-O. This optimized anode enhanced electrode lifetime 122.8 times while the electrochemical activity decreased slightly when compared to the undoped TNT. The effects of current density, initial pH and initial 2,4-dichlorophenoxyacetic acid (2,4-D) concentration were investigated, and the mainly responsible radical for degradation was confirmed to be the surface OH on B, Co-TNT anode. This anode had better performance on the TOC removal, mineralization current density (MCE) and energy consumption (Ec) when compared with BDD, PbO 2 , DSA and Pt anodes, and it also presented a very stable degradation for 10 cycles oxidation of 20 mg/L 2,4-D with allowable Co leaching. Therefore, B, Co-TNT anode is a promising, stable, safety and cost-effective anode for application in electrochemical advanced oxidation processes (EAOPs).
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Journal of Materials Chemistry A
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2020
·Vol. 8
·期 8
·4369-4375
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IF 11.301
Lulu Chen,Yelong Zhang,Lile Dong,Wenxiu Yang,Xiangjian Liu,Ling Long,Changyu Liu,Shaojun Dong,Jianbo Jia
Rational design of isolated metal atom doped carbon catalysts is essential for revealing the essence of high activity for the oxygen reduction reaction (ORR), which can promote the development of robust catalysts for clean energy conversion devices. Herein, we report a simple one-step strategy to prepare Fe and Co atomically supported on N-doped nanocarbon (FeCo-IA/NC) from metal–organic frameworks with excellent ORR activity. The isolated Fe–N4 and Co–N4 sites are characterized by atomic-resolution aberration-corrected scanning transmission electron microscopy and X-ray absorption fine structure spectroscopy. The electrochemical results and density functional theory calculations indicate that the synergetic effect between Fe–N4 and Co–N4 accounts for the enhanced ORR activity. Benefiting from the large BET surface area, microporous feature, and high content (85%) of pyridinic and graphitic N, the well-designed catalyst exhibits better ORR activity (half-wave potential of 0.88 V) and Zn–air battery performances (higher open circuit potential and power density) than commercial Pt/C. This work may lay a foundation for further exploring efficient non-precious metal-based catalysts for the ORR and developing clean energy conversion devices.
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APPLIED SURFACE SCIENCE
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2020
·
IF 6.182
Qiang Liu,Zhuo Li,Qiuwen Liu,Chuchu Cheng,Mingxia Song,Caijin Huang
The Co@BN core–shell nanostructure of Co core and boron nitride (BN) shell was prepared through a facile one-step thermal treatment. The as-prepared Co@BN nanocomposites exhibited excellent dye-sensitized photocatalytic hydrogen evolution activity (13.78 mmol h −1 g −1 ) with visible light and the apparent quantum yield was 1.15%. The enhanced adsorption of EY on the BN shell and the Co/BN Schottky junction facilitate the tandem transfer of photo-generated carriers to the Co surface. Moreover, the core–shell interface serves as a nanoreactor boosting the reduction of H + to H 2 on the Co surface. Additionally, the magnetic recyclability makes Co@BN favorable for its practical application. This work extends the application of the “photocatalysis under shell” and has potential in dye-sensitized solar cell.
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JOURNAL OF MATERIALS SCIENCE
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2020
·Vol. 55
·期 17
·7417-7431
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IF 3.553
Meng Xingtong,Jia Shuai,Mo Lanlan,Wei Jie,Wang Feijun,Shao Ziqiang
Nowadays, it has become a trend to prepare porous carbon as electrode materials for supercapacitors by using biomass and its derivatives by virtue of its low cost, abundant source and environmental friendliness. Carboxymethyl cellulose ammonium (CMC-NH 4 ), a kind of cellulose derivative, is used as a carbon precursor and O/N source to prepare carbon material through cross-linking with aluminum ions, lyophilization, carbonization and activation. The as-prepared O/N-co-doped carbon samples (ONAC-500, ONAC-600 and ONAC-700) exhibit hierarchically porous structure with different size pores in carbon framework, ensuring electrolyte ions effective transport and diffusion. Meanwhile, the ONAC-600 reveals a high specific surface area of 2658 m 2 g −1 , abundantly porous structure with pore volume of 1.32 cm 3 g −1 and effective O/N-doping, which ensure a high capacitance of 465.0 F g −1 at 1 A g −1 in 3 M KOH three-electrode system. It also shows better rate capability and good stability after 10000 cycled under 10 A g −1 . Besides, the assembled all-solid-state supercapacitor with ONAC-600 delivers an acceptable energy density of 7.8 Wh kg −1 at a power density of 124.2 W kg −1 .
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