Journal of Materials Chemistry A
·
2021
·Vol. 9
·期 21
·12807-12817
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IF 12.732
Hao Zhang,Chaohai Wang,Wuxiang Zhang,Ming Zhang,Junwen Qi,Jieshu Qian,Xiuyun Sun,Brian Yuliarto,Jongbeom Na,Teahoon Park,Hassanien Gomaa Abdien Gomaa,Yusuf Valentino Kaneti,Jin Woo Yi,Yusuke Yamauchi,Jiansheng Li
Carbon-based electrodes play important roles in constructing efficient capacitive deionization (CDI) devices. Therefore, the rational design of carbon materials with optimized structure, composition, and morphology is crucial for further improving the CDI performance. Herein, a novel N, P co-doped eave-like hierarchical porous carbon (NP-EHPC) for CDI is reported. To prepare the NP-EHPC, the core–shell ZIF-8@AF particles are first prepared through the kinetically-controlled growth of zeolitic imidazolate framework-8 (ZIF-8) and polymerization of p-aminophenol and formaldehyde (AF), followed by subsequent pyrolysis and post-doping with phosphorus. Owing to the unique eave-like morphology, presence of abundant mesopores, and co-doping of P and N, the NP-EHPC exhibits a high desalination capacity of 24.14 mg g−1 in 500 mg L−1 NaCl solution at 1.2 V and long cycling stability of over 150 cycles. Moreover, the density functional theory (DFT) calculation results reveal that the co-doping of N and P atoms can greatly enhance the binding energies for Na and Cl atoms and lead to superior electrosorption capacity. This work provides a new insight into the design of high-performance carbon materials for the desalination of brackish water.
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Polymers
·
2021
·Vol. 13
·期 8
·1270
·
IF 4.329
Mengyuan Zhang,Zhonghua Chang,Xiaofeng Wang,Qian Li
Biodegradable and bioabsorbable polymers have drawn considerable attention because of their mechanical properties that mimic human soft tissue. Poly(l-lactide-co-ε-caprolactone) (PLCL), the copolymer of L-lactic (LA) and ε-caprolactone (CL), has been applied in many tissue engineering and regenerative medicine fields. However, both the synthesis of PLCL and the structure-activity relationship of the copolymer need to be further investigated to allow tuning of different mechanical properties. The synthesis conditions of PLCL were optimized to increase the yield and improve the copolymer properties. The synthetic process was evaluated by while varying the molar ratio of the monomers and polymerization time. The mechanical properties of the copolymer were investigated from the macroscopic and microscopic perspectives. Changes in the polymerization time and feed ratio resulted in the difference in the LA and CL content, which, in turn, caused the PLCL to exhibit different properties. The PLCL obtained with a feed ratio of 1:1 (LA:CL) and a polymerization time of 30 h has the best toughness and elasticity. The developed PLCL may have applications in dynamic mechanical environment, such as vascular tissue engineering.Keywords:poly(l-lactide-co-ε-caprolactone);synthesis;segment;toughness;elasticity
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PubMed
高影响因子
Journal of Physical Chemistry C
·
2021
·
IF 4.126
Pengfei Yao,Jing Cao,Xue Gong,Ce Han,Mingbo Ruan,Ping Song,Weilin Xu
The development of catalysts free of platinum-group metals with a high performance for the oxygen reduction reaction (ORR) in proton exchange membrane fuel cells is a grand challenge. Herein, we report zeolitic imidazolate framework-8-based Co, N, and S tridoped carbon frameworks (Co–N–S CFs) with high ORR catalytic activity and remarkable durability in an alkaline medium. Results indicate that the high ORR performance of the Co–N–S CFs could be attributed to the unique 3D structure of carbon frames, the synergistic effect among Co, N, and S, and its high electron conductivity. It is also found that the N and S doped heteroatoms can anchor Co atoms by forming CoNx and CoSx active sites for a highly efficient ORR. The results obtained here can help in the design and understanding of the cost-effective highly active Pt-free electrocatalysts.
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Inorganic Chemistry Frontiers
·
2021
·Vol. 8
·期 11
·2725-2734
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IF 6.569
Di Li,Yingying Xing,Changjian Zhou,Yikai Lu,Shengjie Xu,Xiangli Shi,Deli Jiang,Weidong Shi
Due to the low-carbon economy requirement in large-scale industrial applications, exploration of active, robust, resourceful, low-cost and efficient oxygen evolution reaction (OER) electrocatalysts is urgently needed. In this work, we report a Fe–N co-doped cobalt selenide nanosheet array (Fe–N–CoSe2) on nickel foam (NF) as a highly efficient OER electrocatalyst via an anion and cation co-doping strategy using a metal–organic framework (MOF) as the precursor. The nanosheet arrays grown on NF without an additional binder are not only beneficial for accelerating the charge transfer, but also for suppressing electrocatalyst shedding. Furthermore, the nanosheet structure constructed using nanograins could promote electrolyte penetration and gas diffusion and increase the active sites. More importantly, the Fe and N element doping can further provide additional active sites, regulate the electronic structure and boost the OER kinetics. In view of the abovementioned points, the as-prepared Fe–N–CoSe2 electrocatalyst exhibits outstanding OER performance and long-term durability. It affords a current density of 50 mA cm−2 at a small overpotential of 270 mV with a Tafel slope of 62.7 mV dec−1, and the Fe–N–CoSe2 electrocatalyst has only a small attenuation of 1.9% after a 100 h constant test at 100 mA cm−2 in alkaline solution, which is superior to the commercial RuO2 electrode. These results offer a potential approach for the preparation of effective and robust OER electrocatalysts as substitutes to replace the expensive commercial electrocatalysts based on element doping.
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DYES AND PIGMENTS
·
2021
·
IF 4.889
Xiaofeng Sun,Hui Wang,Jinpeng Qi,Shengju Zhou,Hongguang Li
In recent years, it is heartening to witness that carbon dots (CDs), a rising star in the family of carbon nanomaterials , have displayed tremendous applications. However, the investigations toward self-assembly of CDs are still in their infancy. Tannic acid (TA) is a naturally derived polyphenolic compound with special molecular structure. Here, the co-assembly of CDs and TA in aqueous solutions has been investigated. The CDs/TA binary mixtures exhibited rich phase behavior, which went through the process of transparent phase-turbid phase-transparent phase. We focus on investigating the morphologies of the samples. As the concentration of TA increases, the aggregates evolve from the network structures to the spherical aggregates, and finally become the vesicles. Through systemic analysis of changes of zeta potential , morphologies and size distributions at varying temperature and pH, the mechanism of aggregate formation is proposed. The effect of adding TA on the fluorescence properties of CDs aqueous solutions was studied. After integration into aggregates, the potential applications of the CDs in biology and life sciences could be significantly expanded.
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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
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2021
·
IF 5.816
Chunyu Zhang,Guozhu Liu,Bo Ning,Shuairen Qian,Danning Zheng,Li Wang
The electrochemical oxygen reduction reaction (ORR) via two-electron pathway is a sustainable way of producing hydrogen peroxide. Nanostructured carbon materials are proved to be effective catalysts for 2e − ORR. Herein, a series of mesoporous carbon with tunable nitrogen species and oxygen functional groups were synthesized by varying the added amount of dopamine hydrochloride as nitrogen and oxygen source. The modified catalysts exhibited higher content of pyrrolic-N and ether C–O groups which are confirmed by a series of characterization. Raman spectra and correlation analysis revealed that the increased proportion of defect sites in carbon materials are closely related to the introduced pyrrolic-N and ether C–O groups. And the rotating ring-disk electrode (RRDE) measurement carried out in 0.1 M KOH electrolyte showed the H 2 O 2 selectivity increased with the content of defect sites. Among them, the optimized catalyst (NOC-6M) exhibited a selectivity of 95.2% and a potential of 0.71 V vs. RHE at −1 mA cm −2 . Moreover, NOC-6M possessed the high H 2 O 2 production rate of 548.8 mmol g cat −1 h −1 with faradaic efficiency of 92.4% in a two-chamber H-cell. Further mechanistic analysis revealed that the introduction of pyrrolic-N and ether C–O are likely to improve the binding energy of the defect sites toward ∗OOH intermediate, resulting in a more favorable 2e − ORR pathway for H 2 O 2 production.
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POLYMER TESTING
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2020
·
IF 3.275
Lidong Feng,Sheng Xiang,Yanlong Liu,Xinchao Bian,Gao Li,Xuesi Chen
An analytical method was developed to quantitatively determine residual monomers, namely, lactide (LA) and ε -caprolactone (CL), in poly(lactide- co - ε -caprolactone) (PLCL) using an internal-standard method of gas chromatography (GC). PLCL and diphenyl ether (DPE) as an internal standard were initially dissolved in dichloromethane (DCM), and then PLCL was precipitated in cyclohexane. The residual LA and CL monomers in PLCL, as well as DPE, were extracted into cyclohexane from the polymer solution. The resulting solution was directly injected into a GC system. This method was practical for measuring the residual LA and CL contents in PLCL. The relative standard deviation ( RSD ) ( n = 5) denoting the repeatability of this method was less than 5.6% and 4.3% for the LA and CL measurements, respectively, indicating that the method was sufficiently precise. The recovery rate of standard addition was 96.5%–101.5% and 98.4%–104.2% for the determination of LA and CL in PLCL, respectively. The RSD of the recovery of standard addition ( n = 5) was not more than 2.0%, indicating that the method was sufficiently accurate.
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高影响因子
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
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2020
·
IF 4.947
Xiu Li,Yimin Xuan,Qiang Li
Conventional microchannels provide effective chip cooling with constant flow rate and this comes at the cost of high pumping power consumption. Considering the dynamic heat load in reality, a self-adaptive microchannel cooling is desired for regulating the flow rate to diminish the operational cost while preserving the inherent cooling effectiveness. Taking the advantages of easy synthesis, well tunable lower critical solution temperature (LCST) and remarkable mechanical strength, this paper reports the self-adaptive microchannel cooling with the thermal-sensitive nanocomposite (NC) P(MEO 2 MA- co -OEGMA) hydrogel. A novel route is developed to integrate the hydrogel with the chip using template-aided imprint molding and in situ polymerization. Circular hydrogel is elaborately designed and anchored firmly in the channel. The cooling performance is tested with a custom test vehicle under different operating conditions. The hydrogel acts as a smart valve and tailors the flow rate from 0.14 mL/s to 0.46 mL/s based on heat load variation. Compared with conventional channels, heat flux of 100 W/cm 2 can be extracted with similar temperature rise while the coefficient of performance (COP) is improved by an order of magnitude. The transient characteristics and repeatability are also validated. The self-adaptive scheme offers both effective and economical liquid cooling for modern electronic devices.
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Crystals
·
2020
·Vol. 10
·期 10
·922
·
IF 2.404
Xiao Juan Liu,Yang Zhang,Xue Zhong Wang
In situ ATR-FTIR spectroscopy and imaging and image analysis were applied to the study of the multicomponent co-crystallization process involvingS-valsartan and sacubitril in which LCZ696 crystals were formed. LCZ696 is a combination drug for use in heart failure that was approved by the FDA in 2015 following development by Novartis Pharmaceuticals. Though much work was reported on LCZ696 about its pharmacokinetic and pharmacodynamic effects in the evaluation and clinical testing, less attention was paid to study on the co-crystallization process. LCZ696 crystals have shown difficulties in filtration mainly due to the small particle size. In this work, LCZ696 crystals were prepared successfully byS-valsartan and sacubitril, and characterized by SEM, XRPD, TG-DSC and ATR-FTIR. ATR-FTIR and imaging and image analysis were used to monitoring solution concentration and investigating the co-crystallization mechanism. It revealed that the nucleation process was very slow compared with the transformation process, which is indication that the co-crystallization was controlled by nucleation. LCZ696 crystals are composed of very thin hexagonal plates, which seems indicating that LCZ696 crystals grow mainly in two size dimensions. Stirrer speed and crystal seeds were found to have noticeable effect on the induction time, transformation time and crystal size distribution. The Johnson-Mehl-Avrami equation was found to be able to describe the co-crystallization process.Keywords:S-valsartan and sacubitril co-crystallization;LCZ696;ATR-FTIR;On-line process imaging
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JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
·
2021
·
IF 8.067
Guanglu Li,Chang Liu,Zhao Zhang,Baihua Cui,Yanan Chen,Yida Deng,Wenbin Hu
Oxygen evolution and oxygen reduction are considered as essential processes in the energy conversion devices. The progress of cost-effective bifunctional catalysts has become a critical issue to be solved. Here, we report that Co(OH) 2 @N-doped carbon (NC) was facilely synthesized through the impregnation strategy of metal-organic frameworks derived carbon and cobalt ions. N-doped carbon with porous structure and cobalt hydroxide nanosheets play a synergistic effect role, representing excellent catalytic performance toward oxygen evolution and reduction reactions. The obtained Co(OH )2 @NC exhibits remarkable activity in terms of a lower overpotential of 330 mV@10 mA cm −2 for OER and a more positive half-wave potential (E 1/2 = 0.84 V) for ORR in alkaline medium, outperforming IrO 2 and Pt/C. Due to its superior bifunctional catalytic performance, Co(OH) 2 @NC catalyst is applied into a promising air electrode of Zn-air battery. This presented strategy of impregnation synthesis in this work provides a new design direction for practical electrochemical energy devices.
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JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2020
·Vol. 104
·期 6
·2860-2867
·
IF 3.502
Da-Wang Tan,Zhen-Yong Lao,Zhan Zhang,Wei-Ming Guo,Shi-Kuan Sun,Hua-Tay Lin
B 4 C-TiB 2 ceramics (TiB 2 ranging 5~70 vol%) with Mo-Co-WC as the sintering additive were prepared by spark plasma sintering. In comparison with B 4 C-TiB 2 without additive, the enhanced densification was evident in the sintered specimen with Mo-Co-WC additive. Core-rim structured grain was observed around TiB 2 grains. The interface of the rim between TiB 2 and B 4 C phases demonstrated different feature: the inner borderline of the rim exhibited a smooth feature, whereas a sharp curved grain boundary was observed between the rim and the B 4 C grain. The formation mechanism is discussed: the epitaxial growth of (Ti,Mo,W)B 2 rim around the TiB 2 core may occur as a result of the solid solution and dissolution-precipitation between TiB 2 phase and the sintering additive. It was revealed that the fracture toughness increased as the content of TiB 2 content increased, alongside the decreased hardness. B 4 C-30 vol% TiB 2 specimen demonstrated the optimal combination of mechanical properties, reaching Vickers hardness of 24.3 GPa and fracture toughness of 3.33 MPa·m 1/2 .
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MATERIALS CHEMISTRY AND PHYSICS
·
2020
·
IF 3.408
Huimin Guo,Chao Li,Hongxin Hu,Xiaoyan Yu,Kimiyoshi Naito,Qingxin Zhang
Nanodiamonds are novel carbon nanoparticles , which have wide application prospect around various fields owing to the excellent properties. However, nanodiamonds exhibit great tendency to aggregate and this phenomenon extremely limits the application of nanodiamonds. Two simple and green approaches of “grafting from” and “grafting to” are conducted to modify nanodiamonds covalently with copolymer of poly(ϵ-caprolactone) and polyethylene glycol . The characterizations of FT-IR, Raman spectra and TGA indicate that the copolymers are covalently linked on nanodiamonds surface through “grafting from” and “grafting to” methods successfully and the grafting rates are 13.35% and 20.87%, respectively. Moreover, the modified nanodiamonds present smaller particle diameter, less aggregation and better dispersion in organic solvent according to the dynamic light scattering particle size analyzer, transmission electron microscopic analysis and natural sedimentation experiment, which may have potential application at many fields.
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高影响因子
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