CHEMICAL ENGINEERING JOURNAL
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2023
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IF 15.1
Chenxiao Yin,Zhi-Xiong Fei,Jingrui Sun,Lin Weng,Xu Wang,Ke-Ke Yang,Ling-Ying Shi
Low-temperature solid–liquid organic phase change materials (OPCMs) offer tremendous opportunities in thermal management techniques but suffer from leakage problems above the melting temperature. Here, inspired with the universal hydro/organogels using three-dimensional polymer networks capable of holding large amounts of liquid solvents, a kind of form-stable high-enthalpy biphasic phase change organogels (BPCOGs) were developed by the integration of hydrophobic association for synthesizing intrinsic phase change matrices and H-bonding interaction for binding OPCM liquids. The porous phase separated poly(acrylamide-octadecyl acrylate) (P(AM- co -OA)) matrices with uniformly dispersed thermal conductive carbon nanotubes were fabricated from the hydrophobically associating hydrogels (HAHs), in which POA segments provide the phase change energy storage microdomains and the PAM network is capable of binding a series of melted OPCMs by hydrogen bond engineering. The fabricated BPCOGs possess form-stability, high phase change enthalpy (high up to 215.5 J g −1 ) and high energy storage efficiency (>90%), and show excellent electrical/optical-thermal energy conversion as well as shape memory performances. This study provides a universal strategy to prepare flexible biphasic OPCMs suitable for a variety of solid–liquid OPCMs including fatty alcohols, fatty acids and polyethylene glycol, and demonstrates the great potentials of these BPCOGs in solar energy utilization and functional flexible devices.
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Journal of Materials Chemistry A
·
2019
·Vol. 7
·期 25
·15137-15144
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IF 10.733
Lei Hu,Li Gao,Xiaoming Yan,Wenji Zheng,Yan Dai,Ce Hao,Xuemei Wu,Gaohong He
An advanced ion-selective membrane containing a dynamic hydroxyl-based 3D H-bond network is first proposed for improved efficiencies and stability in flow battery applications. The 3D H-bond network structure is constructed by the nanoscale aggregation of hydrophilic dense-hydroxyl side chains anchored to hydrophobic polybenzimidazole. This unique dynamic H-bond network creates proton transport highways as well as vanadium permeation barriers across the membrane, leading to an ultralow vanadium ion permeability (<10−9 cm2 s−1) and remarkably low area resistance (0.32 Ω cm−2). This membrane exhibits high coulombic efficiencies (CE: 98.0–99.2%) and energy efficiencies (EE: 88.9–77.9%) at high current densities (80–200 mA cm−2), together with a long lifetime of over 800 cycles (about 42 days) at 120 mA cm−2 in vanadium flow batteries. The design of dynamic 3D H-bond networks provides a promising strategy for the development of highly ion-selective and stable membranes for flow battery application.
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JOURNAL OF CATALYSIS
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2019
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IF 7.723
Xiaoyue Wan,Qi Zhang,Mingming Zhu,Yi Zhao,Yongmei Liu,Chunmei Zhou,Yanhui Yang,Yong Cao
Site-selective deoxygenation of hydroxyl groups represents essential processes to access valuable functionalized bio-based compounds with industrial potential. One of the challenging tasks in this context is to convert biodiesel-derived glycerol in the presence of abundant water directly to 1,3-propanediol (1,3-PDO), a key component of the emerging polymer industry. Herein, a monometallic iridium supported on H-ZSM-5 in the absence of Re oxophilic metal oxides was prepared via grinding-assisted impregnation procedures and attempted as an effective and recyclable catalyst for the aqueous-phase selective hydrogenolysis of glycerol toward 1,3-PDO in the absence of acid additives. The results revealed the necessity to control the Ir domain dispersions, Ir 0 /Ir 3+ ratio and the amounts of overall acid/Brönsted acid sites. Activity depended linearly on the amount of overall and Brönsted acid sites, and 1,3-PDO selectivity increased in the presence of Ir-induced Brönsted acid sites, denoted as Ir-O(H)-H-ZSM-5. We speculate that Ir-O(H)-H-ZSM-5 are generated by the interfacial synergistic interaction between IrO x and H-ZSM-5 through hydrogen spillover and reverse hydrogen spillover according to the reported literatures. The reaction mechanism to elucidate the role of Ir-O(H)-H-ZSM-5 sites in glycerol hydrogenolysis was also postulated based on extensive characterization and catalytic reaction results.
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RARE METALS
·
2024
·
IF 9.6
Li Zhao-Yang,Zhao Wei-Jun,Sun Yu,Zhou Bing,Feng Yue-Zhan,Liu Chun-Tai
The pressing demand for ultrathin and flexible shields to counter electromagnetic interference (EMI) has sparked interest in Ti 3 C 2 T x MXene materials due to their exceptional electrical conductivity, tunable surface chemistry, and layered structure. However, pure Ti 3 C 2 T x MXene films often lack the mechanical properties required for practical engineering applications, and traditional reinforcement methods tend to reduce electrical conductivity. This work demonstrates an effective strategy to enhance the alignment and densely packed layered structure of Ti 3 C 2 T x MXene films by regulating the acidity and alkalinity of Ti 3 C 2 T x MXene aqueous solutions. This approach simultaneously improves mechanical strength and electromagnetic interference shielding effectiveness (EMI SE). Compared with original Ti 3 C 2 T x MXene films, MXene films modified with ammonia solution (NH 3 ·H 2 O) via OH − show a significant improvement in tensile strength (27.7 ± 1.9 MPa). Meanwhile, MXene films treated with hydrochloric acid (HCl) via H + reach an even higher tensile strength of 39 ± 1.5 MPa. Moreover, the EMI SE values of the treated MXene films increase significantly, each reaching 66.2 and 58.4 dB. The maximum improvements in EMI SE values for the acid- and alkali-treated samples are 17.9% and 4%, respectively. In conclusion, the simultaneous enhancement of mechanical strength and EMI shielding efficacy highlights the potential of acid- and alkali-treated Ti 3 C 2 T x MXene films for applications in ultrathin and flexible EMI shielding materials. Graphical abstract
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CEMENT AND CONCRETE RESEARCH
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2024
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IF 10.9
Binmeng Chen,Xu Fang,Yuyang Zhao,Zongjin Li
In recycling and reusing construction waste, carbonation of recycled concrete fine (RCF) has been successfully applied to produce value-added products, such as silica nanoparticles, via the breaking of calcium silicate hydrate (C-S-H) structure and condensation of silicate chains. However, the intricacies of carbonation of RCF with varying calcium to silicon (C/S) ratios and their implications on the size of generated silica nanoparticles remain unknown. In this work, we developed an optimized carbonation method at high water to solid ratio to fabricate silica nanoparticles from C-S-H with different C/S ratios. The particle size of silica nanoparticles was found to gradually decrease with the increased C/S ratio of C-S-H. Since as C/S ratio increased, silicate in Q 3 state shifted to Q 1 state and the silicate chain became shorter, shifting from long-range, disordered to short-range, ordered. As the disordered self-seeding growth of long silicate chains derived from C-S-H continued, the Si-O-Si network of silica nanoparticles became chaotic, leaving more unreacted Si-OH on its surface. On the contrary, the short silicate chains displayed higher possibility of condensation, making nanoparticles with a smaller diameter.
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JOURNAL OF PHYSICAL ORGANIC CHEMISTRY
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2012
·Vol. 26
·期 1
·23-29
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IF 1.963
Chang-Di Chen,Wen-Bing Sheng,Guo-Jun Shi,Can-Cheng Guo
The regioselective hydroxylation of the aromatic C–H bond on a series of naphthalenes with different β-substituent R (R = H, Me, Et, i -Pr, OMe, COOH, Br, etc.) was studied, and the substituent effect on the regioselectivity was investigated. The electron-donating substituent afforded the aromatic C–H bond hydroxylation at the 1α position with more than 80% selectivity, while the electron-withdrawing substituent afforded the aromatic C–H bond hydroxylation at the 4α position with more than 60% selectivity of β-substituted naphthalene hydroxylated with metachloroperbenzoic acid catalyzed by tetrakis(pentafluorophenyl)porphyrin manganese(III) chloride. The research showed that the steric and electronic effects of the substituent appeared to play a significant role in determining the regioselectivity, and the electronic effect was of more importance than the steric effect of the substituent in the current situation. The studies may provide additional proofs for the stepwise mechanism of the aromatic C–H bond hydroxylation through a cationic intermediate. Copyright © 2012 John Wiley & Sons, Ltd.
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JOURNAL OF ALLOYS AND COMPOUNDS
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2017
·
IF 3.133
Chuanling Sun,Dajiang Mei,Jingli Xu,Yuandong Wu
Two new mixed bismuth (III) tellurite nitrate/sulfate, H[Bi 3 O(Te 3 O 9 )](NO 3 ) 2 and [Bi 2 (TeO 3 ) 2 ](SO 4 ) were synthesized under hydrothermal conditions. H[Bi 3 O(Te 3 O 9 )](NO 3 ) 2 crystallizes in the hexagonal space group P 6 ¯ 2 m (No. 189) with lattice parameters a = 9.8465(4), b = 9.8465(4), c = 4.1917(4) Å, V = 351.95(4) Å 3 , Z = 1, while [Bi 2 (TeO 3 ) 2 ](SO 4 ) crystallizes in the monoclinic space group C 2/ c (No. 15) with lattice parameters a = 15.7657(13), b = 7.4285(5), c = 8.0959(6) Å, β = 112.693(2) ° , V = 874.75(11) Å 3 , Z = 4. The structure of H[Bi 3 O(Te 3 O 9 )](NO 3 ) 2 features one-dimensional cationic 1 ∞ [Bi 3 O(Te 3 O 9 )] + chains along c axis, which are composed of [BiO 7 ] and [TeO 4 ] polyhedra by sharing corners and edges, whereas [Bi 2 (TeO 3 ) 2 ](SO 4 ) possesses a new three-dimensional framework consisting of two-dimensional zigzag layers of 2 ∞ [Bi 2 (TeO 3 ) 2 ] 2+ that are linked by SO 4 2- anions. Title compounds were characterized by single-crystal X-ray diffraction, powder X-ray diffraction, Raman spectra, infrared spectra and solid state UV-vis-NIR diffuse reflectance spectroscopy .
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ORGANIC & BIOMOLECULAR CHEMISTRY
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2014
·Vol. 12
·期 18
·2969-2978
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IF 3.487
Jiajun Zhang,Pinhua Li,Lei Wang
A novel KOAc-promoted α-position C–H activation and alkynylation of ethers with alkynyl bromides to 2-alkynyl ethers has been developed under transition-metal-free and simple reaction conditions. In addition, this methodology can also be extended to the vinylation of ethers with vinyl bromides in excellent regio- and stereo-selectivity. A wide range of direct C(sp)–C(sp3) and C(sp2)–C(sp3) bonds has been formed through this protocol, which offers a new and alternative route.
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PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2015
·
IF 4.321
Lei Yue,Guangqian Li,Guijin He,Yongsheng Guo,Li Xu,Wenjun Fang
The precise investigations on modeling properties and performance of practical fuels are usually complicated because of the multi-component nature. On the basis of hydrogen to carbon ratio (H/C), as a simple and overall characterization parameter for hydrocarbon fuels, this work provides a comprehensive insight into the study of kerosene-based hydrocarbon fuels (H/C = 1.6–2.3). The fundamental properties and supercritical cracking performance of hydrocarbon fuels are influenced intrinsically by their H/C values and molecular weights ( M ) due to the compositional and structural effects. Thus, a new combined parameter, (H/C)/ M a , is proposed to model the performance of hydrocarbon fuels. It is found that the hydrocarbon fuel with a higher H/C has a higher net heating value, and that with a higher (H/C)/ M 0.1 has a lower density. The viscosity decreases with the increase of (H/C)/ M 0.5 . The flash point shows a decreasing trend against the increase of (H/C)/ M 2 . The densities, viscosities and net heating values of 23 hydrocarbon fuels are calculated by means of the regression equations with the H/C and M data, and they are in agreement with the corresponding experimental values with the relative errors less than 2.5%, 10% and 1.5%, respectively. As investigated in an electrically heated tube reactor, the hydrocarbon fuel with a higher H/C performs thermal cracking more easily, absorb more heat and form fewer cokes. As a result, the cracking performance of hydrocarbon fuels can be predicted reasonably to a certain extent on the basis of H/C values.
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ORGANIC & BIOMOLECULAR CHEMISTRY
·
2014
·Vol. 12
·期 21
·3493-3498
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IF 3.487
Yaping Zhao,Lu Sun,Tieqiang Zeng,Jiayi Wang,Yanqing Peng,Gonghua Song
Copper-catalyzed direct olefination of benzaldehydes into 1,3-diarylpropenes by a novel domino Knoevenagel-decarboxylation-Csp3-H activation sequence is reported. This method provides a concise and effective route toward the synthesis of unsymmetrical 1,3-diarylpropene derivatives.
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PubMed
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CERAMICS INTERNATIONAL
·
2016
·
IF 2.758
Fengrui Zhai,Shuang Li,Jialin Sun,Zhongzhou Yi
h -BN-SiC ceramic composites with different SiC contents were fabricated by spark plasma sintering . The results indicate that the addition of hard SiC particles has a remarkable effect on the densification, microstructure, mechanical properties and thermal shock resistance of the composites. Compared with pure h -BN ceramic, the relative density and mechanical properties of h -BN-SiC ceramic composites were improved obviously. The optimal properties of h -BN-SiC ceramic composites were obtained at SiC content of 25%, and the relative density, flexural strength and fracture toughness reached 97.8%, 289.2 MPa and 3.45 MPa m 1/2 , respectively. Moreover, the relationship of fracture toughness and fracture mode was discussed. The thermal shock test results showed that the h -BN-SiC ceramic composite with the SiC content of 25% exhibited excellent thermal shock resistance, presenting critical temperature difference up to 900 °C. The high temperature oxidation of h -BN and SiC on material surface led to the formation of borosilicate glass phase, which could heal the surface microcracks and then improve the thermal shock resistance.
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POLYMER
·
2024
·
IF 4.1
Zaoxia Wen,Liang Xu,Xingyu Liu,Linxuan Fang,Lianbin Wu
A novel method was developed for constructing cross-linked silsesquioxane, utilizing Q-type H-POSS as a precursor. The Piers-Rubinsztajn (P–R) like reaction of Q-type H-POSS was catalyzed by B(C 6 F 5 ) 3 , resulting in the production of a prepolymer containing partial Si–H. Upon heating at high temperature in air, the prepolymer transformed into an insoluble and infusible cross-linked polymer, named Cured poly(H-POSS). This polymer exhibited high thermostability, with a 5 % weight loss temperature ( T 5d ) of 709 °C and a residue of 92 % at 800 °C. Additionally, Cured poly(H-POSS) exhibited high transparency, with a transmittance of 90 % in the 400–800 nm wavelength range, and favorable dielectric properties, with a dielectric constant ( D k ) of 2.88 at 14 GHz.
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