Journal of Materials Chemistry A
·
2020
·Vol. 8
·期 45
·23906-23918
·
IF 11.301
Xiang Zhang,Shibin Wang,Chenshuo Wu,Hong Li,Yi Cao,Shenggang Li,Haibing Xia
In this work, S-doped AuPbPt alloy nanowire-networks (NWNs) are synthesized by conformal growth of Pt onto S-doped AuPb NWNs as templates, which are obtained by NaBH4 reduction of an extended network of 2 nm Au nanoclusters resulting from Pb2+ ion-directed self-assembly. The contents of Pb and S in the S-doped AuPb NWNs are optimized in order to create the appropriate content of PtS in the resulting S-doped AuPbPt alloy NWNs because Pb in both AuPb3 and PbS is involved with the formation of PtS and PbPtx during the conversion of S-doped AuPb NWNs to S-doped AuPbPt alloy NWNs. Moreover, the formation of an optimal content of PtS in the resulting S-doped AuPbPt alloy NWNs remarkably downshifts the d-band center of Pt, on the basis of results from X-ray Photoelectron Spectroscopy (XPS) characterization and density functional theory (DFT) calculations, and then improves the resistance of active Pt sites against oxidation and in turn renders the Pt surfaces more catalytically active for the ORR and more structurally stable. Furthermore, the as-prepared S-doped AuPbPt alloy NWNs indeed exhibit excellent electrocatalytic activity towards both the ORR (e.g., Eonset = 1.047 V and E1/2 = 0.921 V) and HER (Eonset = −2 mV and overpotential of 12 mV at 10 mA cm−2) in acidic media with excellent durability because of the presence of an optimal amount of PtS, based on the results of control experiments and DFT calculations.
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CHINESE JOURNAL OF POLYMER SCIENCE
·
2020
·Vol. 38
·期 7
·685-695
·
IF 3.154
Wang Sheng,Cai Si-Liang,Zhang Jie,Wan Xin-Hua
A series of novel cis poly(phenylacetylene)s (PPAs) substituted at meta -position(s) by two alkoxycarbonyl pendants, i.e. , sP-Me-C8/rP-Me-C8 , P-Me-C12 , sP-Et-C4 , sP-2C4 and sP-Oct-C4 , were synthesized under the catalysis of [Rh(nbd)Cl] 2 (nbd = norbornadiene). The dependence of elongation, screw sense, and stimuli response of helical polyene backbone on the structure of pendant, solvent, and temperature was systematically investigated in both solution and solid states. Because of n → π * interaction between vicinal carbonyl groups, sP-Me-C8/rP-Me-C8 could adopt contracted cis-cisoid helix in THF, toluene, CH 2 Cl 2 , and CHCl 3 . Such an intramolecular interaction was sensitive to the hydrogen bond donating ability of solvent and temperature, but insensitive to the dielectric constant and polarity of solvent. In poly(3-methoxycarbonyl-5-alkoxycarbonylphenylacetylene), the longer the chiral alkyl chain was, the easier the stable cis-cisoid helix could be achieved. However, when the methoxycarbonyl was changed to ethoxycarbonyl, sec -butyloxycarbonyl, and octyloxycarbonyl pendant groups, only cis-transoid helix was obtained at room temperature due to the increased steric hindrance. Moreover, lowering temperature was found to facilitate the stabilization of n → π * interactions, and reversible temperature-dependent stereomutations were achieved in sP-Me-C8 and sP-Et-C4 depending on the solvent where they were dissolved. These results suggested that the long alkyl chain, small pendant size, and lower temperature favored the stabilization of intramolecular n → π * interactions and the formation of contracted, cis-cisoid helices for poly(3,5-diester substituted phenylacetylene)s.
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Bioresources and Bioprocessing
·
2019
·Vol. 6
·期 1
·1-12
·
IF 0
Zhang Can,Song Wei,Liu Jia,Chen Xiulai,Liu Liming
( R )- or ( S )-2-Hydroxy-4-(methylthio)butanoic acid (HMTBA) is used as a poultry nutritional supplement and to treat renal failure disease. Herein, we report an artificially designed biocatalytic cascade process, which uses l -methionine to synthesize ( R )- or ( S )-HMTBA. This biocatalysis cascade comprises a basic module and two different extender modules and operates in a modular assembly manner. The basic module responsible for the transformation of l -methionine to α-keto-γ-methylthiobutyric acid (KMTB) is comprised of the l -amino acid deaminase. Two different extender modules responsible for the transformation of KMTB to ( R )- or ( S )-HMTBA are comprised of the R/S-specific lactate dehydrogenase in combination with the formate dehydrogenase, respectively. Engineered Escherichia coli catalysts, one containing the basic module, the other containing the one of two different extender modules, produced 97.6 g L −1 ( R )-HMTBA and 96.4 g L −1 ( S )-HMTBA with a yield of 96.9% and 95.8% at the large scale (1 L) using a two-stage strategy in one pot, respectively. Therefore, this biocatalytic process lays the foundation for the industrial-scale conversion of low-cost l -amino acids to corresponding high-value enantiopure chiral 2-hydroxy acids.
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JOURNAL OF SOILS AND SEDIMENTS
·
2017
·Vol. 17
·期 8
·2202-2213
·
IF 2.522
Ou Taosha,Guan Mengyun,Mai Yongrui,Deng Peiyan,Xiao Yutang,Deng Dayi
Purpose Surface sediments contaminated with high levels of multiple heavy metal(loid) species are very common environmental problems. Especially, the labile and bioaccessible fractions of heavy metal(loid)s in the sediments are posing serious risks to the biota and the overlaying water quality. This study aimed at developing a potential method to manage the activity of the labile fractions of heavy metal(loid)s in surface sediments. Materials and methods This study assessed the feasibility of adding iron powder, a low-cost industrial by-product, to sediments containing high levels of Pb, As, and Cd to adsorb labile fractions of heavy metal(loid)s onto the sorbent surfaces and to retrieve the heavy metal(loid) laden powders by applying external magnetic field. In addition, the redistribution of Pb, Cd, and As in different sediment fractions, the dissolved fraction and the sorbent-adsorbed fraction, was also investigated and characterized. Results and discussion The results indicate that the bioactive labile fractions (exchangeable and carbonate-bound fractions) of heavy metal(loid)s are prone to concentrating onto iron powders and can be selectively removed from the sediments by magnetic retrieval. In addition, iron addition induces conversion of labile fractions of heavy metal(loid)s into more stabilized fractions. Conclusions Overall, the process can effectively minimize the activity of labile fractions of heavy metal(loid)s in surface sediments.
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ELECTROCHIMICA ACTA
·
2022
·
IF 7.336
Jiaqi Xu,Zongcai Deng,Bo Wu,Meijin Lin,Dongyang Chen
Organic polymers containing redox-active moieties have attracted increasing attention as electrode materials for high-performance rechargeable batteries due to their sustainability, flexibility, environmentally benign, and high stability. Herein, viologen functionalized fluorene-containing poly(arylene ether ketone)s (MV-FPAEKs) were synthesized by polycondensation , bromination, and quaternization in sequence. 1 H NMR was used to monitor the degree of functionalization (DF), which increased with the increasing of the molar ratio of the bromination agent. The MV-FPAEK-96 with a DF of 96% for viologen was used as the active material for polymer cathode. The theoretical specific capacity was calculated to be 87.6 mAh g −1 based on the dual electron transfer per viologen unit. It had been found that the MV-FPAEK-96 battery delivered a discharge specific capacity of 87.1 mAh g −1 at a current rate of 0.1 C, and maintained 32.1 mAh g −1 after 100 galvanostatic cycles. In contrast, the small molecule of dimethyl viologen was highly soluble in the electrolyte, and the corresponding capacity decreased to negligible values after only 20 cycles. Therefore, the attachment of viologen to polymeric backbones is an effective strategy to increase the stability in electrolyte while maintaining the rechargeability, and the MV-FPAEK-96 is a promising redox-active candidate for polymer batteries.
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ACS Applied Energy Materials
·
2023
·
IF 6.4
Jiaqi Xu,Zhoulin Ye,Zongcai Deng,Dongchu Chen,Qilang Lin,Dongyang Chen
Polymer batteries have attracted increasing attention because of their advantages of good flexibility, high compatibility with organic electrolytes, and high environmental friendliness. However, the low utilization rate of the redox-active units buried in polymeric network and the slow kinetics of the electrochemical reactions hinder their development. Herein, mono- and diviologen functionalities are attached to a tetramethylbiphenol-derived poly(arylene ether ketone) (TPAEK) by postmodification to yield two redox-active polymers MV-TPAEK and 2MV-TPAEK, respectively, and polymer electrodes are prepared by mixing them with N-doped carbon nanotubes without binders. When paired with the Li counter electrode, the MV-TPAEK and 2MV-TPAEK electrodes deliver specific discharge capacities of 93.3 and 95.4 mA h g–1, respectively, at a current rate of 0.1 C and maintain 36.1 and 42.3 mA h g–1, respectively, after 100 galvanostatic cycles. When the current rate is increased to 10 C, the specific discharge capacities are lowered to 13.9 and 25.8 mA h g–1, respectively, for the MV-TPAEK and 2MV-TPAEK electrodes due to the increased electrochemical polarizations. All of these results prove that the 2MV-TPAEK electrode is better than the MV-TPAEK electrode. When the counter electrode is changed to Na, the trend remains the same. Given the fact that the two polymers have an identical backbone, the improved electrochemical performance of 2MV-TPAEK may be ascribed to the larger mobility of the extended 2MV pendant, which is beneficial for the formation of more molecular voids and stacked intermediate structures for better charge transfer. This study paves the way for the molecular design of redox-active polymers for high-performance polymer batteries.
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MATERIALS SCIENCE IN SEMICONDUCTOR PROCESSING
·
2023
·
IF 4.1
Zhengqiaoruo Zhu,Nan Zhou,Yakun Li,Xiaoli Zhang,Linlin Zhang
Due to their unique persistence in the environmental cycle, pharmaceuticals and personal care products (PPCPs) are increasing concern in the scientific community. Therefore, the development of new energy-saving and environmentally compatible technologies to remove these pollutants is highly requested. In this work, an S-scheme photocatalytic nanoreactor was synthesized by Fe 2 O 3 nanoparticles to S doped carbon nitride nanosheets . The unique structure of S-scheme Fe 2 O 3 /SCN heterojunction enhances its optical absorption and has a large number of active sites and photogenerated carrier separation. Consequently, the Fe 2 O 3 /SCN demonstrated excellent photo-Fenton degradation activities under visible light irradiation. Remarkedly, 5 mg/L of norfloxacin is completely photo-Fenton degraded following 25 min under visible light irradiation. It further shows that ·OH and ·O 2− play an important role in the photo-Fenton catalytic reaction , leading to the decomposition of norfloxacin. The degradation of tetracycline further demonstrates that this photo-Fenton catalytic system can be effectively used to remediate pharmaceutical and personal care product contamination in environmental waterways.
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Journal of Biomedical Nanotechnology
·
2024
·Vol. 20
·期 6
·1041-1048
·
IF 2.9
Li Shizheng,Lv Yanwei,Liu Xiaoying,Yuan Yuan
Chronic wounds in diabetic patients have become a common complication. However, current wound management tends to yield unsatisfactory outcomes and may give rise to complications. Therefore, we prepare a nano-structured lipid carrier by incorporating a 20(S)-Protopanaxadiol (PPD)-loaded
lipid nanoparticles (PPD-N) into a silicone elastomer (PPD-NS) for treating chronic diabetic wounds and assess its therapeutic efficacy in promoting diabetic wound healing and vascular regeneration in a mouse model. Our findings revealed that the prepared PPD-N showed uniform distribution
with spherical morphology and an average diameter of approximately 130 nm. Moreover, PPD-NS exhibited a wound closure rate of 92.1% after 48 hours of treatment and demonstrated enhanced vascular regeneration. Therefore, it can be concluded that the prepared PPD-NS can effectively be used in
diabetic wound repair and vascular regeneration. This study provides a promising potential therapeutic option for diabetic wounds.
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Processes
·
2022
·Vol. 10
·期 7
·1359
·
IF 3.352
Xiaoyu Huo,Chao Jia,Shanshan Shi,Tao Teng,Shaojie Zhou,Mingda Hua,Xiangdong Zhu,Shicheng Zhang,Qunjie Xu
Potassium thiocyanate (KSCN), a highly efficient “three birds with one stone” activator, might work with inorganic activators to produce excellent N/S co-doped porous carbon (NSC) materials for environmental remediation. However, the effects of inorganic activators on cooperative activation are unclear. As a result, the influence of inorganic activators on the synthesis of NSC materials was investigated further. This study shows that the surface areas of the NSC materials acquired through cooperative activation by potassium salts (KOH or K2CO3) were considerably higher than those acquired through KSCN activation alone (1403 m2/g). Furthermore, KSCN could cooperate with K2CO3to prepare samples with excellent specific surface area (2900 m2/g) or N/S content. The as-prepared NSC materials demonstrated higher adsorption capability for chloramphenicol (833 mg/g) and Pb2+(303 mg/g) (pore fitting, complexation). The research provides critical insights into the one-step synthesis of NSC materials with a vast application potential.Keywords:N/S co-doping;porous carbon;chloramphenicol adsorption;Pb2+removal
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CRYSTENGCOMM
·
2016
·Vol. 18
·期 20
·3703-3710
·
IF 3.849
Qingshuang Liang,Keke Huang,Xiaoru Ren,Wei Zhang,Renguo Xie,Shouhua Feng
In this work, Cu–Sb–S nanocrystals (NCs) with various compositions and crystal structures are realized by only tuning the amount of 1-dodecanethiol (DDT). When the DDT amount is 3.6, 5.5, 20.5, and 25.6 mmol, pure tetragonal Cu3SbS4, cubic Cu12Sb4S13, orthorhombic CuSbS2, and orthorhombic Cu3SbS3 NCs are respectively obtained. Systematic investigations demonstrate that different amounts of DDT are responsible for formation of the different compositions and crystal structures of the initial Cu2−xS seeds, which results into the formation of various Cu–Sb–S NCs. This reaction path is further verified by control experiments from successful preparation of Cu–Sb–S NCs comparable to that of the as-prepared ones directly from the reaction of Sb2S3 NCs with Cu2−xS seeds. The current study not only provides a facile and economical way to synthesize high-quality Cu–Sb–S NCs, but also opens a new route for preparation other I–V–VI multicomponent chalcogenides NCs, such as Cu–Bi–S systems.
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Polymer Chemistry
·
2019
·Vol. 11
·期 6
·1211-1219
·
IF 4.76
Fu-Rong Zeng,Jing Xu,Lin-Hao Sun,Jimei Ma,Hong Jiang,Zi-Long Li
Poly(ester amide)s (PEAs) attract considerable attention owing to their intriguing properties. However, the establishment of precise structure–property relationship for PEAs is hindered by the ambiguous primary structures of these biologically important polymers. Herein, we propose polyesterification as an efficient strategy for the synthesis of copolymers of ε-caprolactone (CLo) and ε-caprolactam (CLa). Two sorts of AB-type monomers bearing halogen and carboxylic acid terminal groups, namely 6-bromohexanoic acid (1) and 6-(6-bromohexanamido)hexanoic acid (2), underwent nucleophilic substitution in a step-growth manner to furnish P(CLo) (P0) and P(CLo-alt-CLa) (P5), respectively. Moreover, random copolymers P1–P4 were also synthesized by copolymerization of 1 and 2 in predetermined feed ratios. Thermal properties, crystal structure, surface wettability, thermal responsiveness and degradation profiles of P0–P5 along with P(CLa) (P6) were investigated. The melting ranges of polymers P0–P6 become narrowed if the structural regularity is pronounced, and the melting temperatures (Tms) are fundamentally determined by chemical composition and sequence distribution. The crystal structures and morphologies of P0–P6 are influenced by their chemical compositions, and the unit cell changes from orthorhombic to α-monoclinic while increasing the molar fraction of the CLa unit. Moreover, alternating copolymer P5 shows upper critical solution temperature (UCST) behavior in dimethyl sulfoxide (DMSO).
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FUEL
·
2019
·
IF 5.128
Tengfei Yang,Congcong Liu,Chuan Li,Liyong Gan,Wenan Deng,Qingshan Niu
Nickel sulfide is regarded as one of the most promising substitutes for the best-performing disposable molybdenum catalyst in the hydrogenolysis of lignite and heavy residue, but its practical application is hindered severely by insufficient catalytic activity and a prohibitively large dosage. Herein, we report that the issues of activity and cost of nickel sulfide can be addressed simultaneously by employing a combination of iron incorporation and a dispersing strategy via oil-soluble ligands. Motivated by first-principles calculations where iron incorporation in nickel sulfide would lead to a better activity towards the rate-limiting step of hydrogenolysis compared with nickel sulfide alone, we successfully prepared a well-dispersed Fe-Ni-S catalyst by coordinating active metal salts with carboxylate ligands and a subsequent essential sulfurization. The synthesized Fe-Ni-S catalyst outperformed not only the monometallic nickel catalyst but also the commercial molybdenum catalyst in the hydrogenolysis of lignite and heavy residue, and exhibited a high conversion efficiency, hydrogen consumption, hydrogen/carbon product atomic ratio, and dispersibility of solid residues, with an economic nickel dosage of as low as ~250 μg·g −1 . Structural changes of raw coal and solid residues further confirmed the role of the Fe-Ni-S catalyst in facilitating the hydrogenolysis of lignite and heavy residue.
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危险品化学品经营许可证（带存储）