REACTIVE & FUNCTIONAL POLYMERS
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2021
·
IF 3.975
Zhitao Hu,Xiaohui Cao,Huahua Huang,Yongming Chen
Poly( ε -caprolactone) (PCL) has been one of the most important biomaterials, but its instinct hydrophobicity and slow biodegradation limit its broad applications. Herein, copolymerization of CL and a hydrophilic macrolactone, 2-oxo-15-crown-5 ether (O15C), was achieved through ring opening polymerization catalyzed by 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) using benzyl alcohol as the initiator at room temperature . A series of poly(CL- co -O15C) copolymers with different O15C contents were prepared by simply tuning the feeding ratio of [CL]/[O15C]. They showed molecular weights ranging from 11.0 to 20.6 kg mol −1 , and polydispersity index between 1.4 and 1.6, characterized by SEC (Size Exclusion Chromatography). Analysis of 1 H NMR indicated that the copolymers belong to a random copolymer structure. The introduction of O15C had a significant influence on thermal stability, hydrophilicity and degradability of the copolymers. With increasing the O15C content, the crystalline ability of PCL segment among the copolymers reduced, while the hydrophilic property was improved obviously. Through hydrolysis experiment, the poly(CL- co -O15C) with O15C content of 38 mol% exhibited a much faster degradable rate than that of the copolymer with O15C content of 10 mol%. Therefore, copolymerization of CL with a crown ether monomer via organic catalyst mediated ROP will be a feasible strategy for modification of polyester materials.
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MACROMOLECULAR CHEMISTRY AND PHYSICS
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2021
·Vol. 223
·期 12
·2100321
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IF 2.527
Guanchen He,Heng Li,Junpeng Zhao
One-step synthesis of well-defined block copolymer is of great fundamental and practical values. Here, an aromatic-aliphatic block copolyester is one-step synthesized from the mixture of phthalic anhydride (PA), cyclohexene oxide (CHO), and δ -valerolactone ( δ -VL) at room temperature in the presence of a metal-free Lewis pair catalyst consisting of triethylborane and excess phosphazene base. Alcohol-initiated ring-opening alternating copolymerization of PA and CHO occurs first and selectively because of the overwhelmingly higher activity of PA than CHO and δ -VL toward the reaction with base-activated hydroxy species. Only after full conversion of PA is reached can ring-opening polymerization of δ -VL occur from the terminus of the aromatic polyester so that a well-defined (AB) n C m type block copolyester is formed. The two polymerizations are both highly chemoselective without homopolymerization of CHO or extensive transesterification reactions. Owing to the sequence-selective and living characteristics of the terpolymerization, hepta- and undecablock copolyesters with controlled molar mass and low dispersity are obtained through addition of the three-component monomer mixture in batches. Applicability of the method to propylene oxide and ε -caprolactone is also examined.
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CHEMICAL ENGINEERING JOURNAL
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2021
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IF 13.273
Jiaqing Liu,Jun Wan,Lin Liu,Weijie Yang,Jingxiang Low,Xiaoming Gao,Feng Fu
Aiming to the unwanted photocatalytic hydrogen production systems using sacrifice agents, a well-design S-scheme O-ZnIn 2 S 4 /TiO 2- x heterojunction was fabricated to realize photocatalytic hydrogen production via water reduction coupled with organic oxidative dehydrogenation. As supported by DFT calculations and experimental analysis, owing to the synergistic effect of oxygen defect and doping engineering, a tailored energy band structure alignment with higher redox potentials and larger Fermi level potential difference are achieved, resulting in more efficient S-scheme interface charge transfer and separation efficiency, thus improving the photocatalytic activity of O-ZnIn 2 S 4 /TiO 2- x . The optimal O-ZnIn 2 S 4 /TiO 2- x photocatalyst shows remarkable H 2 and benzaldehyde production rate of 2584.9 μmol g -1 h −1 and 2880.5 μmol g -1 h −1 under visible light, which are 52.5 and 66.4 times as high as those over blank TiO 2 . Interestingly, this coupled reaction system also displays superior H 2 evolution activity compared to sacrificial reagent systems of Na 2 SO 3 /Na 2 S and triethanolamine. Further quenching and EPR experiments reveal that both water and organic molecules provide protons for H 2 production.
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NANOTECHNOLOGY
·
2021
·Vol. 33
·期 10
·105501
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IF 3.874
Yunxia Yang,Qian Liu,Yisong Zhao,Jianmin Chen,Bing Chen,Yanling Yan,Faming Gao
The electrode material is vital for the performance of the electrochemical biosensor. Lately, many nanomaterials have been developed to improve the sensitivity and detection efficiency of the biosensors. In this work, a kind of one-dimensional nanomaterials, the CuPt alloy nanotubes with an open end (CuPt alloy NTs-AOE), was explored. The nanotubes with an open end can provide a larger electrochemical active surface area and more active sites for the immobilization of enzyme. The CuPt alloy displays excellent conductivity and catalytic activity. In addition, the Cu shows the great affinity to thio-compounds, which can greatly enhance the detection efficiency and sensitivity. As a result, the prepared biosensor demonstrates the wider linear range of 9.98 × 10−10–9.98 × 10–5 g l−1 for fenitrothion and 9.94 × 10−11–9.94 × 10–4 g l−1 for dichlorvos (as model OPs ) and with the lower detection limit of 1.84 × 10–10 g l−1 and 6.31 × 10–12 g l−1 (S/N = 3), respectively. Besides, the biosensor has been used to detect the real samples and obtains satisfactory recoveries (95.58%–100.56%).
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APPLIED CATALYSIS B-ENVIRONMENTAL
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2021
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IF 19.503
Yingtong Zou,Yezi Hu,Andrej Uhrich,Zewen Shen,Baoxiang Peng,Zhuoyu Ji,Martin Muhler,Guixia Zhao,Xiangke Wang,Xiaoxiang Xu
We provide a distinct understanding on the role of oxygen vacancies (OVs) for visible light-triggered aerobic oxidation of alcohols via comparative studies on three kinds of Nb 2 O 5 , i.e., undoped, Ti-doped and Ce-doped Nb 2 O 5 . With benzyl alcohol and 5-hydroxymethylfurfural as representative alcohol substrates, we show that fast alcohol oxidation with high selectivity can be achieved on these doped Nb 2 O 5 containing abundant OVs. However, the functionality of OVs is dependent on the properties of dopants as Ce-doped Nb 2 O 5 exhibits a better performance than Ti-doped one. Investigations indicate that the Ce dopants incur little distortion to the structure of Nb 2 O 5 and induce more accessible OVs than Ti dopants for the dissociative chemisorption of alcohol molecules which supports favorable interfacial electron migration process. The present work not only reveals the difference of oxygen vacancies caused by varied metal doping but provides a unique insight in the relation between OVs structure and photocatalytic alcohol oxidation.
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JOURNAL OF COLLOID AND INTERFACE SCIENCE
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2021
·
IF 8.128
Ziqiang Zheng,Ting Wang,Fang Han,Qing Yang,Benxia Li
The development of visible light responsive photocatalysts for simultaneous production of hydrogen (H 2 ) fuel and value-added chemicals is greatly promising to solve the energy and environmental issues by improving the utilization efficiency of solar energy. Herein, the three-component Ni/(Au@CdS) core–shell nanostructures were constructed by the hydrothermal synthesis followed with photodeposition. The intimate integration of plasmonic Au nanospheres and visible-light responsive CdS shells modified with Ni cocatalyst facilitated the generation and separation of electron-hole pairs as well as reduced the overpotential of hydrogen evolution. The Ni/(Au@CdS) photocatalyst exhibited excellent performance toward the selective transformation of benzyl alcohol under anaerobic conditions, and the yields of H 2 and benzaldehyde reached up to 3882 and 4242 μmol·g −1 ·h −1 , respectively. The apparent quantum efficiency (AQE) was determined to be 4.09% under the irradiation of 420 nm. The systematic studies have verified the synergy of plasmonic effect and metal cocatalyst on enhancing the photocatalysis. This work highlights the desirable design and potential application of plasmonic photocatalysts for solar-driven coproduction of H 2 fuel and high-value chemicals.
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APPLIED CATALYSIS B-ENVIRONMENTAL
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2021
·
IF 19.503
Xiaoli Li,Ting Wang,Ziqiang Zheng,Qing Yang,Can Li,Benxia Li
Developing photocatalysts for coproduction of hydrogen fuel and valuable chemicals is highly desired but still challenging. Herein, Pd-modified defective HNb 3 O 8 photocatalyst (denote as Pd/HNb 3 O 8 -H 2 ) consisting of dispersive Pd sites and abundant surface oxygen vacancies (V O s) was prepared via the thermal treatment of Pd 2+ -incorporated HNb 3 O 8 in H 2 /Ar gas. The existence of Pd favors the formation of V O s on HNb 3 O 8 , enabling the synchronous construction of Pd and V O dual active sites. The spectroscopy and photoelectrochemical studies demonstrate the advantages of Pd/HNb 3 O 8 -H 2 photocatalyst in promoting the separation and migration of photoinduced charge carries. The Pd/HNb 3 O 8 -H 2 photocatalyst exhibits the outstanding performance toward photocatalytic proton reduction coupled with selective benzyl-alcohol oxidation , achieving the optimal production rates of H 2 and benzaldehyde as high as 3.17 and 2.76 mmol·g cat −1 h −1 , respectively. The experimental and theoretical investigations have expounded the synergistic mechanism of Pd and V O dual active sites in boosting photocatalytic coproduction of H 2 and benzaldehyde.
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Journal of Materials Chemistry A
·
2021
·Vol. 9
·期 26
·14710-14721
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IF 12.732
He Huang,Wanyue Ye,Caicheng Song,Yingcen Liu,Xiaotong Zhang,Yu Shan,Yuzhen Ge,Shufen Zhang,Rongwen Lu
The selective oxidation of primary carbon–hydrogen bonds in the methyl group of toluene to corresponding oxygenates is of immense significance. This transformation, however, remains challenging and often requires either extensive optimization of the present chemical operating processes or, more importantly, the design and development of novel catalysts. In this paper, we achieve the confinement of uniform Au nanoparticles by using Silicalite-1 (Au@Silicalite-1) via an improved impregnation method for solvent-free oxidation of toluene by oxygen to benzaldehyde. In situ Ar+ etching XPS experiments revealed that in the evolution of Au0 and Au3+ species in a single Au@Silicalite-1 crystal the proportion of the Au3+ species becomes enriched from 0 on the surface to >80% in the center. In the synergetic catalysis between Au0 and Au3+ species, it was observed that the electron-rich Au0 species activated oxygen to form superoxide anion radicals, while the electron-deficient Au3+ species promoted activation of the primary carbon–hydrogen bond in toluene and enabled efficient desorption of the desired product benzaldehyde with selectivity >90%. For comparison, Silicalite-1 or SiO2 supported Au0-rich catalysts exhibited strong adsorption of benzaldehyde, generating overoxidized benzoic acid as the main product.
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Biomaterials Science
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2021
·Vol. 9
·期 9
·3348-3361
·
IF 6.843
Yaomin Zhai,Juan Wang,Liyan Qiu
The in vivo delivery of nanomedicine is severely hampered by the limited enhanced permeability and retention effect (EPR) in tumors. Aiming at overcoming this limitation and achieving high anti-tumor effect of chemotherapeutics, we specially addressed an available strategy from a viewpoint of increasing the drug loading of nano-carriers. Here, we constructed a novel pH-responsive polymersome based on the drug-driven self-assembly of amphiphilic polyphosphazenes PAP containing the ortho ester group ABD and mPEG2000. Due to the non-covalent attractive forces between PAP and doxorubicin hydrochloride (DOX·HCl), DOX·HCl can induce the self-assembly of PAP via embedding itself in the lamella to form vesicles and the subsequent location in the center aqueous chamber of the resultant nano-vesicles, which resulted in the high drug loading content of 35.77 wt%. In addition, with the incorporation of cholesteryl hemisuccinate (CholHS), the premature leakage of DOX·HCl was significantly inhibited under physiological conditions. Meanwhile, the pH-sensitive drug release occurred at pH 5.5 by the advantage of the pH-sensitive biodegradation of ABD in PAP. Consequently, this CholHS-incorporated DOX·HCl-driven PAP vesicle achieved excellent anti-tumor effect with tumor growth inhibition up to 82.4% in S180 tumor-bearing mice. Taken together, our newly developed drug-driven vesicles may promote the development of efficient drug delivery systems for application in cancer therapy.
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DALTON TRANSACTIONS
·
2021
·Vol. 50
·期 30
·10501-10514
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IF 4.39
Xuqiang Hao,Dingzhou Xiang,Zhiliang Jin
Herein, a novel amorphous monodisperse Co3O4 quantum dots/3D hexagonal CdS single crystals (0D/3D Co3O4 QDs/CdS) p–n heterojunction was constructed by a simple hydrothermal and electrostatic self-assembly method. The amorphous monodispersed Co3O4 QDs (≈4.5 nm) are uniformly and tightly attached to the surface of the hexagonal CdS single crystals. The sample, 0.5% CQDs/CdS exhibits outstanding hydrogen evolution activity of 17.5 mmol h−1 g−1 with a turnover number (TON) of 4214, up to 10.3 times higher than that of pure CdS. The enhanced photocatalytic activity can be attributed to the synergistic effect of the p–n heterostructure and the quantum confinement effect of Co3O4 QDs, which significantly promoted the separation efficiency of photo-generated electrons and holes. Additionally, the sulfur vacancy also can act as electron trappers to improve carrier separation and electron transfer. The photoelectrochemical and time-resolved fluorescence (TRPL) results further certify the effective spatial charge separation. This work gives an insight into the design of the 0D/3D Co3O4 QDs/CdS p–n heterostructure for a highly efficient photocatalysis.
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ELECTROPHORESIS
·
2021
·
IF 3.535
Hui Jiang,Hao Zhang,Shi-Jun Yin,Min Lu,Xu Wang,Feng-Qing Yang
Profiling of lipid–water partition coefficients ( K L/W ) of drugs is an essential issue during the early stage of drug development. In this study, two liposomes, including 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) + cholesterol (Chol) (DSPC/Chol liposomes) and soybean lecithin (SPC) + Chol (SPC/Chol liposomes), were prepared for the liposome electrokinetic chromatography (LEKC) analysis, and the logarithm of lipid–water partition coefficients (log K L/W ) of neutral and ionic drugs were determined based on an iterative method. The log K L/W values determined by the SPC/Chol or DSPC/Chol liposomes LEKC were linearly fitted, which showed a good fitting coefficient ( R 2 = 0.89). Furthermore, the linear relationship between the data obtained from LEKC system and octanol–water system, immobilized artificial membrane, Caco-2 cell model, and software prediction was analyzed, respectively. Results illustrated that DSPC/Chol liposomes or SPC/Chol liposomes had a good linear relationship with Caco-2 cell model, and R 2 was 0.81 and 0.72, respectively. Moreover, the linear free energy relationship analysis suggested that the solute volume, hydrogen bond basicity, and J – were the main descriptors that drove the partition process of solutes in the SPC/Chol or DSPC/Chol LEKC system. In addition, the normalized properties of the SPC/Chol and DSPC/Chol LEKC systems through linear free energy relationship analysis were very close. In short, DSPC/Chol liposomes are more suitable for simulating cell membranes than SPC/Chol liposomes, and the developed LEKC is an effective partitioning model for measuring the log K L/W of drugs.
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FOOD CONTROL
·
2021
·
IF 5.548
Dandan Qi,Aiqing Miao,Wei Chen,Wenwen Wang,Xiugu He,Chengying Ma
Broken oolong-black tea is an innovative tea in China produced by applying characteristic manufacture crafts of broken oolong tea (bruising) and broken black tea (fermentation) on the manufacture of tea and it has both aroma features of broken oolong tea and broken black tea. The aim of this study is to investigate the differences of the volatile compounds among broken oolong-black, broken oolong and broken black tea made by Huangzhixiang (HZX) and Huangdan (HD) varieties by gas chromatography-mass spectrometry (GC-MS) combined with chemometirc analysis. The results suggested significant differences on both aroma quality and volatile compounds profile of three kinds of tea. Chemometric analysis showed that 47 and 52 differential volatile compounds were identified to distinguish three kinds of teas made by HZX and HD, respectively, and the differences of volatile compounds among the tea samples were mostly quantitatively rather than qualitatively. Besides, compounds with floral and fruity aroma increased in broken oolong-black tea compared with the others, while compounds with green aroma decreased in broken oolong-black tea. Quantitative descriptive analysis of the aroma showed that sweet aroma was a new trait of broken oolong-black tea compared with broken oolong tea while green aroma disappeared compared with broken black tea. Our results provide the theoretical and practical meaning for the application of two characteristic crafts from different tea manufacture on the innovation of tea manufacture.
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