SOLAR ENERGY MATERIALS AND SOLAR CELLS
·
2023
·
IF 6.9
Xuefeng Shao,Yeke Chenxu,Binrui Wang,Nan Zhang,Yanping Yuan
Towards latent heat storage for days, or even extending to months in the context of solar energy utilization, the exploration of phase change materials (PCMs) with stable supercooling and the following crystallization triggering are carried out. The present work confirmed the persistent supercooling property of the xylitol/erythritol eutectic mixture. The coupled technique combining mechanical agitation with seeding was proposed to trigger crystallization, so as to facilitate the heat retrieval whenever heat is in demand. The xylitol/erythritol eutectic keeps supercooling state without crystallization at ambient temperature for at least 10 days, thus it can serve as applicable PCM for controllable heat retrieval. Such severe supercooling is mainly attributed to the particular molecular structure of polyalcohols and dramatic increase of dynamic viscosity . In particular, on the basis of secondary nucleation principle, the coupled technique combining mechanical agitation and seeding can be a preferable technique to efficiently trigger crystallization of the present eutectic PCM , so as to realize controllable heat retrieval. Such combined technique has main advantages of high efficiency and reproducible crystallization process . The agitation duration is shortened to 1.8 min with seeding, in comparison to a longer value of 43.3 min without seeding. Although the single technique of mechanical agitation can also trigger the crystallization, the agitation is found to be time-consuming and the triggered crystallization process is in poor consistency among parallel specimens. Furthermore, the crystallization initiating is greatly advanced with high agitation rate (300 r/min), and the agitation duration to sufficiently activate crystallization can be significantly shortened. The results suggest that appropriately high agitation rate favors the efficient heat retrieval. The obtained results are helpful to gain a better understanding on the supercooled PCMs based controllable heat retrieval.
研究领域:
材料科学
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热能存储
·
物理化学
·
能源材料
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传热学
✓ 已验证
DOI
高影响因子
INORGANICA CHIMICA ACTA
·
2023
·
IF 2.8
Tian-Yu Zhang,Xue-Qian Wu,Heng-Yu Ruan,Yi Yuan,Le Wang,Ya-Pan Wu,Qing-Wen Han,Ruan Chi,Dong-Sheng Li
Designing economical and efficient anode catalysts is critical for the commercial use of direct alcohol fuel cells (DAFCs). In this work, a novel Ni(II)-based metal–organic framework (MOF), {[Ni 3 ( μ 3 -OH)(TMBTI)(1,4-bib)(H 3 O)} n (H 6 TMBTI = 2,4,6-trimethylbenzene-1,3,5-triylisophthalate, 1,4-bib = 1,4-bis(1-imidazoly)benzene) (CTGU-38, CTGU = China Three Gorges University), was successfully synthesized through solvothermal method. Structural analyses reveal that the CTGU-38 possesses a unique Ni 6 ( μ 3 -OH) 2 (COO) 12 cluster and 3D porous framework with a rare (6,16)-connected topology. Further electrochemical experiments demonstrate that the CTGU-38 exhibits good electrocatalytic oxidation performance towards various alcohol fuel molecules, including the methanol oxidation reaction (MOR), ethanol oxidation reaction (EOR), n -propanol oxidation reaction (NPOR), and isopropanol oxidation reaction (IPOR), with peak current densities ranging from 26.9 to 54.46 mA cm −2 in alkaline solution. These results indicate that the CTGU-38 appears to be a potential non-noble metal-based electrocatalyst for DAFCs, and this work provides new insights into the design of more efficient electrocatalysts at the atomic scale for energy conversion.
研究领域:
材料科学
·
电化学
·
能源转换
✓ 已验证
DOI
高影响因子
Scientific Reports
·
2015
·Vol. 5
·期 1
·1-11
·
IF 5.578
Feng Yan,Ye Feng,Liu Hui,Yang Jun
Mastery over the structure of nanoparticles might be an effective way to enhance their performance for a given application. Herein we demonstrate the design of cage-bell nanostructures to enhance the methanol tolerance of platinum (Pt) nanoparticles while remaining their catalytic activity for oxygen reduction reaction. This strategy starts with the synthesis of core-shell-shell nanoparticles with Pt and silver (Ag) residing respectively in the core and inner shell regions, which are then agitated with saturated sodium chloride (NaCl) solution to eliminate the Ag component from the inner shell region, leading to the formation of bimetallic nanoparticles with a cage-bell structure, defined as a movable Pt core enclosed by a metal shell with nano-channels, which exhibit superior methanol-tolerant property in catalyzing oxygen reduction reaction due to the different diffusion behaviour of methanol and oxygen in the porous metal shell of cage-bell structured nanoparticles. In particular, the use of remarkably inexpensive chemical agent (NaCl) to promote the formation of cage-bell structured particles containing a wide spectrum of metal shells highlights its engineering merit to produce highly selective electrocatalysts on a large scale for the cathode reaction of direct methanol fuel cells.
研究领域:
材料科学
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电化学
·
纳米技术
✓ 已验证
DOI
PubMed
高影响因子
ELECTROCHIMICA ACTA
·
2020
·
IF 6.215
Chongyang Zhang,Xigui Yue,Jiashuang Luan,Peiyao Li,Shuling Zhang,Jun Liu,Guibin Wang
In light of the essential role of typical reinforced PEMs (Gore-SELECT®) in pursuing novel alternatives, we demonstrate for the first time the potent capability of pore-filled semi-crystalline poly (ether ether ketone) membranes that represent by far the most effective polymer materials for methanol blocking of direct methanol fuel cells. The stable structure of poly (ether ether ketone) matrixes contributes to a low swelling behavior so as to restrain the methanol permeation across membranes in high concentration methanol solutions. Porous matrixes are endowed with the ability to conduct protons by an inorganic modifier of phosphotungstate-ionic liquid. In order to improve the interaction of phosphotungstate-ionic liquid and inert matrixes, the porous matrix is pre-modified by a co-deposition reaction of polydopamine and polyethyleneimine. The anchored modifier of polydopamine and polyethyleneimine in the matrix decelerates the leakage of ionic liquid and phosphotungstate. The developed composite membrane performs a heightened proton conductivity up to 0.11 S cm −1 at 80 °C to benefit from the superior proton conductive capacity of the phosphotungstate-ionic liquid, and exhibits extremely low methanol crossover (4.5 × 10 −7 cm 2 s −1 ) and favorable selectivity (12.22 × 10 4 S s cm −3 ) compared to those of Nafion 117. Especially, an excellent single cell performance with a maximum power density of 107 mW cm −2 is carried out under 10 M methanol at 70 °C.
研究领域:
材料科学
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能源工程
✓ 已验证
DOI
高影响因子
SYNTHETIC COMMUNICATIONS
·
2024
·
IF 1.8
Haiyan Xu,Yuanyuan Huang,Yinchun Liang,Nan Wang,Dejun Dong,Mengke Wang,Weichun Huang,You Zi,Zhanping Yang
Herein, we present an efficient synthesis method utilizing Bi quantum dots (QDs) as catalysts for the photochemical oxidative coupling of thiols to disulfides under mild conditions. The protocol offers low catalyst loading, simplicity in reaction setup as well as high efficiency. Aromatic thiols and aliphatic thiols are successfully transformed into disulfides with good to quantitative yields, demonstrating tolerance to various substituents and heterocycles. Additionally, the protocol extends to the synthesis of asymmetric disulfides and allows for gram-scale synthesis.
研究领域:
催化
·
有机化学
·
纳米技术
✓ 已验证
DOI
高影响因子
Molecular Catalysis
·
2022
·
IF 5.089
Shengnan Zhao,Song Song,Yong You,Yingtian Zhang,Wei Luo,Kaijie Han,Tong Ding,Ye Tian,Xingang Li
Heterogeneous photocatalytic C-C coupling is a green and efficient approach to producing valuable chemicals. The strategies for guiding effective photocatalyst design are desired but still limited. Here, we report visible-light-driven highly selective photocatalytic C-C coupling of benzyl alcohol over surfactant-modified Zn 3 In 2 S 6 semiconductors. A complete switch of product selectivity from benzyl aldehyde (91.5 %) to C-C coupling products (96.5 %) is obtained by the modification of Zn 3 In 2 S 6 with stearyl trimethyl ammonium bromide (STAB). This modification assists the formation of sulfur vacancies on Zn 3 In 2 S 6 to enhance charge carrier separation, thereby increasing the photocatalytic activity. The selectivity switch is mainly attributed to increasing conduction band position of Zn 3 In 2 S 6 by surfactant modification which strengthens the reduction ability of photogenerated electrons to induce the reversible reduction of benzyl aldehyde to ketyl radicals, and partially to the poor oxidation ability of the material that inhibits the oxidation of ketyl radicals to benzyl aldehyde. Encouragingly, this universal protocol has been successfully applied to a series of aromatic alcohols and biomass-derived furanic alcohols to selectively produce C-C coupling products.
研究领域:
化学
·
材料科学
·
光催化
·
环境科学
✓ 已验证
DOI
高影响因子
JOURNAL OF ELECTROANALYTICAL CHEMISTRY
·
2020
·
IF 3.807
Yifu Wang,Dan Wang,Jilin Wang,Lulu Wang
Ammonium functionalized anion exchange silica precursor (AESP) is synthesized by 3-(2-Aminoethylamino) propyltriethoxysilane and (2, 3-epoxypropyl) trimethylammonium chloride. Then the corresponding series of membranes based on pyridine functionalized polyvinyl alcohol (PVA-Py) with varying AESP content are prepared using sol-gel method. Obtained membranes show ion exchange capacities (IEC) ranging from 0.54 mmol·g −1 to 0.92 mmol·g −1 , but the opposite trend of water uptakes (WU) from 123.97% down to 69.09% because of the formation of organic-inorganic network. The hybrid membranes also exhibit good thermal stability (>140 °C), excellent mechanical properties (25.37 MPa) and high OH − conductivity (9.63 × 10 −2 S·cm −1 , 80 °C). Compared with the commercial Nafion®-117 membrane, the prepared hybrid membrane performs a much lower methanol permeability (7.57 × 10 −8 cm 2 ·s −1 for prepared membrane, 2.00 × 10 −6 cm 2 ·s −1 for Nafion®-117 membrane, 3 M methanol solutions, 30 °C). Only 10.7% decreases in OH − conductivity can be observed in 6 M 80 °C NaOH solutions after 360 h immersions, exhibiting excellent alkaline stability. The highest peak power density of the single cell with 5 M KOH + 3 M methanol fuel is 52.56 mW·cm −2 at 80 °C and 0.2 MPa O 2 .
研究领域:
材料科学
·
能源工程
✓ 已验证
DOI
高影响因子
COMPOSITES SCIENCE AND TECHNOLOGY
·
2017
·
IF 4.873
Chunmei Li,Jiaojun Tan,Junwei Gu,Ying Xue,Lei Qiao,Qiuyu Zhang
A novel method was developed to encapsulate 1-benzyl-2-methylimidazole (1B2MZ) to produce microcapsule-type latent curing agent using thiol-click reaction in an oil/water emulsion. The fabrication process was significantly simplified and required reaction time was greatly shortened due to the efficiency of click chemistry. In the oil phase, 1B2MZ was mixed with reactive monomers , 1,3,5-tri-2-propenyl-1,3,5-triazine-2,4,6 (1H, 3H, 5H)-trione (TTT) and tris[2-(3-mercaptopropionyloxy)ethyl] isocyanurate (TEMPIC) which would polymerize to result in polythioether shell of microcapsules by following a photoinitiated thiol-ene mechanism. Polyvinyl alcohol (PVA) aqueous solution acted as water phase. The whole reaction process lasted for 20 min, which was enough for almost full conversions of monomers . The generated latent curing agent had good spherical shapes with smooth outer surfaces and the mean diameter distributed in the range of 105.7 to 18.17 μm by adjusting PVA concentration or viscosity of oil phase. The curing behavior, kinetics and releasing mechanism of latent curing agent were studied by differential scanning calorimetry (DSC) and scanning electron microscope (SEM). This microcapsule-type latent curing agent had a long storage life for 30 days when mixed with epoxy resin at 20 °C, and the mixture could be cured at 100 °C within 1 h.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
JOURNAL OF POWER SOURCES
·
2014
·
IF 5.211
Mingyu Li,Gang Zhang,Shuai Xu,Chengji Zhao,Miaomiao Han,Liyuan Zhang,Hao Jiang,Zhongguo Liu,Hui Na
A novel type of cross-linked proton exchange membrane of lower methanol permeation and high proton conductivity is prepared, based on a newly synthesized sulfonated cross-linker: carboxyl terminated benzimidazole trimer bearing sulfonic acid groups (s-BI). Compared to membranes cross-linked with non-sulfonated cross-linker (BI), SPEEK/s-BI-n membranes show higher IEC values and proton conductivities. Meanwhile, oxidative stability and mechanical property of SPEEK/s-BI-n membranes are obviously improved. Among SPEEK/s-BI-n membranes, SPEEK/s-BI-2 exhibits high proton conductivity, low swelling ratio (0.122 S cm −1 and 15.2% at 60 °C, respectively) and low methanol permeability coefficient. These results imply that the cross-linked membranes prepared with the newly sulfonated cross-linker are promising for the direct methanol fuel cells (DMFCs) application.
研究领域:
材料科学
·
能源工程
✓ 已验证
DOI
高影响因子
ACS Omega
·
2017
·
IF 0
Shuyi Wu,Yang Zhang,Jiarui Han,Zhining Xie,Jun Xu,Baohua Guo
To improve the properties of poly(butylene succinate) (PBS), a series of poly[(butylene succinate)-co-poly(tetramethylene glycol)]s (PBSTMGs) with different poly(tetramethylene glycol) (PTMG) contents were successfully prepared by the catalyzed melt polycondensation process. The effect of introducing flexible PTMG segments on the properties was investigated, and they were compared to those of PBS. The differential scanning calorimetry results indicated that the melting temperature, crystallization temperature, and crystallinity of PBSTMG copolymers were slightly lower than those of PBS. Furthermore, these thermal parameters decreased gradually with the increase of PTMG content. Dynamic mechanical analysis showed that there was a significant decline of storage modulus (E′) in the overall temperature range of copolymers compared to that of PBS. The incorporation of PTMG did not modify the crystal lattice of PBS according to the wide-angle X-ray diffraction analysis. Because of copolymerization, the size of the spherulites was reduced at high PTMG contents. The soft domain in the copolymers might contribute to the enhanced tear strength of PBSTMG. The elongation at break and impact strength of PBSTMG copolymers were greatly improved as a result of the phase separation structure and lower degree of crystallinity. Especially, when the PTMG content was 10 mol %, the impact strength of the copolymer reached up to 4.5 times that of PBS. In addition, with more soft segments introduced, the biodegradability of the copolymers became much better than that of PBS.
研究领域:
材料科学
·
高分子化学
✓ 已验证
DOI
JOURNAL OF CHROMATOGRAPHY B-ANALYTICAL TECHNOLOGIES IN THE BIOMEDICAL AND LIFE SCIENCES
·
2018
·
IF 2.441
Xiaoyu Lu,Min Fang,Yu Dai,Yue Yang,Ali Fan,Jiaqiu Xu,Zhiying Qin,Yang Lu,Di Zhao,Xijing Chen,Ning Li
PEGylation techniques have been increasingly employed in drug delivery system and chemical modification of compounds with low aqueous solubility. Triacontanol (TA) is a natural product with several pharmacological activities, but its low aqueous solubility significantly limited its application. PEGylated triacontanol (PEG-TA) was designed as the prodrug to improve the aqueous solubility and pharmacokinetic properties of TA. On the basis of salting-out assisted liquid-liquid extraction (SALLE) and saponification sample preparation procedure, a reliable gas chromatography tandem mass spectrometric (GC–MS/MS) method was developed and validated for the quantification of PEG-TA and its metabolite TA in rat plasma after separation and transformation. Acetonitrile-methanol (9:1, v/v) and ammonium acetate (10 M) were utilized to separate PEG-TA and TA (including conjugated TA with fatty acid). Saponification facilitated the complete conversion of PEG-TA into TA, so PEG-TA could be indirectly quantified. The results revealed that the GC–MS/MS method had excellent selectivity, accuracy and linearity. Calibration curves were linear (R 2 >0.99) within the range of 20.0–1000.0 ng/mL for TA and 100.0–10,000.0 ng/mL for PEG-TA. The intra- and inter-day precision of quality control samples were within 15%, and their accuracy values varied from 93.54% to 113.38%. This analytical method has been successfully applied to pharmacokinetic study of PEG-TA. This study can facilitate the further exploration and quantification of PEGylated prodrugs.
研究领域:
药物化学
·
分析化学
·
药理学
✓ 已验证
DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
·
2020
·Vol. 45
·期 2
·705-713
·
IF 3.288
Samuthirarajan Senthilkumar,Wei Zhong,Mookan Natarajan,Chunxin Lu,Binyu Xu,Xiaoming Liu
An efficient and green protocol for aerobic oxidation of benzylic alcohols in ethanol using CuI–Y zeolite catalysts assisted by TEMPO (TEMPO = 2,2,6,6-tetramethyl-1-piperidine-N-oxyl) as the radical co-catalyst in the presence of atmospheric air under mild conditions is reported. The CuI–Y zeolite prepared via ion exchange between CuCl and HY zeolite was fully characterized by a variety of spectroscopic techniques including XRD, XPS, SEM, EDX and HRTEM. The incorporation of Cu(I) into the 3D-framework of the zeolite rendered the catalyst with good durability. The results of repetitive runs revealed that in the first three runs, there was hardly a decline in activity and a more substantial decrease in yield was observed afterwards, while the selectivity remained almost unchanged. The loss in activity was attributed to both the formation of CuO and the bleaching of copper into the liquid phase during the catalysis, of which the formation of CuO was believed to be the major contributor since the bleaching loss for each run was negligible (<2%). In this catalytic system, except TEMPO, no other additives were needed, either a base or a ligand, which was essential in some reported catalytic systems for the oxidation of alcohols. The aerobic oxidation proceeded under mild conditions (60 °C, and 18 hours) to quantitatively and selectively convert a wide range of benzylic alcohols to corresponding aldehydes, which shows great potential in developing green and environmentally benign catalysts for aerobic oxidation of alcohols. The system demonstrated excellent tolerance against electron-withdrawing groups on the phenyl ring of the alcohols and showed sensitivity to steric hindrance of the substrates, which is due to the confinement of the pores of the zeolite in which the oxidation occurred. Based on the mechanism reported in the literature for homogenous oxidation, a mechanism was analogously proposed for the aerobic oxidation of benzylic alcohols catalysed by this Cu(I)-containing zeolite catalyst.
研究领域:
化学
·
催化
·
绿色化学
·
材料科学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）