Polymer Chemistry
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2022
·Vol. 13
·期 10
·1437-1445
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IF 5.364
Yongjie Zhang,Xiaopei Li,Wenqin Zhu,Pibo Liu,Juntao Ren,Shangtao Chen,Yanming Hu,Guangyuan Zhou
Post-modification of polyolefins by cutting-edge C–H activation has recently emerged as an attractive methodology for the incorporation of precise functionalities, thus expanding their applicability and creating value-added materials. In this report, chromone (CM), the core of naturally occurring molecules possessing manifold biological and pharmacological activities, was incorporated into polyethylene (PE) through the recently developed radical-mediated alkane C–H activation approach. The reaction was conducted in the presence of di-tertbutyl peroxide as the oxidant and a small amount of naphthalene as the solvent or under solvent-free conditions. The produced CM-grafted PEs (CM-PEs) exhibited intriguing antioxidative and fluorescence properties as revealed by thermogravimetric analysis (TGA) and fluorescence microscopy. Moreover, CM-PEs were successfully demonstrated to act as a polymer-bound antioxidant, a fluorescence marker for plastic sorting, and a traceable compatibilizer for the PE/polystyrene blend, revealing that CM-PE is a multi-functional material.
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JOURNAL OF RARE EARTHS
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2022
·
IF 4.632
Feng Lin,Yudan Zhong,Yulong Ma,Yonggang Sun,Xiuqin Men,Yingbo Zhu
Hydrodeoxygenation (HDO) of renewable lignin-derived biomass in aqueous-phase to produce high value-added products is of great significance. However, developing new catalysts with high activity and excellent stability in an aqueous phase faces considerable challenges. Rare earth doping can effectively regulate the water exchange rate constant (WERC) value of the catalyst and play an important role in promoting the hydrolysis of ether bonds. Therefore, in this paper the bimetallic supported catalyst Ni–La 2 O 3 /H-ZSM-5 doped with rare earth metal La 2 O 3 was prepared, and used to catalyze the conversion of the lignin model compound guaiacol to cyclohexanol in the aqueous phase. The conversion of guaiacol catalyzed by 10Ni–3La 2 O 3 /H-ZSM-5 reaches 100%, and the selectivity of the product cyclohexanol is 85%. A series of characterizations illustrate that the doping of La 2 O 3 causes the electron transfer between La 2 O 3 –Ni and changes the distribution of Ni, and a strong metal carrier interaction occurs between the bimetallic Ni–La 2 O 3 and H-ZSM-5. This can effectively promote the hydrolysis of the C–O ether bond in guaiacol and significantly improve the activity of the catalyst. The possible catalytic reaction mechanism of Ni–La 2 O 3 /H-ZSM-5 catalytic conversion of guaiacol was proposed.
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Journal of Advanced Ceramics
·
2021
·Vol. 10
·期 6
·1317-1325
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IF 6.707
Liu Zetan,Zhao Shiqiang,Yang Tian,Zhou Ji
It is possible to improve the machinability of aluminum nitride-hexagonal boron nitride (AlN-h-BN) ceramics while maintaining high strength and high thermal conductivity. The composite ceramics with 0–30 wt% BN as secondary phase were prepared by hot pressed sintering, using yttrium oxide (Y 2 O 3 ) as sintering aid. The phase composition, density, microstructure, mechanical properties, thermal conductivity, and dielectric properties were investigated. The sintering additives were favorable to purify the grain boundaries and improve densification, reacting with oxide impurities on the surface of raw material powder particles. The optimum BN content improved the flexural strength and fracture toughness of composite ceramics with 475 MPa and 4.86 MPa·m 1/2 , respectively. With increasing the amount of BN, the thermal conductivity and hardness of composites gradually decreased, but the minimum value of thermal conductivity was still 85.6 W·m −1 ·K −1 . The relative dielectric constant and dielectric loss tangent of the samples ranged from 6.8 to 8.3 and from 2.4 × 10 −3 to 6.4 × 10 −3 , respectively, in 22–26 GHz.
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高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Cuishuang Jiang,Mingyi Zhang,Guojun Dong,Tong Wei,Jing Feng,Yueming Ren,Tianzhu Luan
It is highly desirable but challenging to control nitrate contamination using photocatalytic reduction technology over non-mental catalysts. Herein, hexagonal boron nitride (h-BN), a typical non-metal catalyst, was employed to photocatalytic denitration in water with formic acid (FA) as a hole scavenger. Compared with a mental catalyst TiO 2 and a non-mental catalyst g-C 3 N 4 , h-BN obtained a more effective reduction performance with nitrate conversion of 97.16% and N 2 selectivity of 95.42%. After three cyclic use, it still presented excellent reduction activity and structure stability. In the h-BN system, the initial pH had a significant effect on the nitrate reduction performance because it determined the surface charge property of the catalyst or the dispersibility in water, and the presence of anions slightly decreased the nitrate conversion process since the competitive adsorption of NO 3 – or NO 2 – . Photocatalytic denitration over h-BN was well according with the Extended-Langmuir-Hinshelwood model. By comparing the average stoichiometric ratio of consumed FA and removed NO 3 – (i.e. experiment value) with the theoretical value, it was determined that there were additional electrons involved in the reduction reaction in addition to CO 2 •- radicals, which was also supported by the quenching experiments. Moreover, CO 2 •- radicals were mainly responsible for the conversion of NO 2 – to N 2 . Exposed B atoms on the h-BN edges behaved as the adsorption sites of nitrogen oxide anions. This study provides a proof-of-concept demonstration of non-mental photocatalyst h-BN for more effective management of nitrate contamination.
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DIAMOND AND RELATED MATERIALS
·
2021
·
IF 3.315
Xiaoyu Zhang,Juan Yi,Yanan Yin,Yiheng Song,Chuanxi Xiong
In recent years, with the increasing demands of portable and high-speed electronic devices, highly integrated equipment attracts people's attention more and more. However, it is a great challenge to guarantee the long-term stability of electronic products at high temperatures. Hexagon boron nitride (h-BN), which owned excellent thermal conductivity and insulation properties , was preferred for electronics. For better compatibility of inorganic fillers and silicone rubber, a biological modification by coating polydopamine (DA) on h-BN was adopted. Herein, the composites based on h-BN@PDA and silicone rubber were fabricated. Compared with h-BN/silicone rubber composites , the thermal conductivity of h-BN@PDA/silicone rubber composites increased and volume resistance of materials had been decreasing. When the amount of h-BN@PDA fillers was 30 wt%, the thermal conductivity of h-BN@PDA/silicone rubber composite increased to 0.95 W m −1 K −1 . The volume resistivity of 30 wt% h-BN@PDA/silicone rubber composite reached 2.5 × 10 11 Ω·cm, which was the lowest one among others, which still exceeded requirements of electronic materials.
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Materials Chemistry Frontiers
·
2020
·Vol. 4
·期 4
·1158-1163
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IF 6.788
Zewen Zhuang,Yu Wang,Zheng Chen,Dingsheng Wang,Chen Chen,Qing Peng,Yadong Li
Densely populated metal atomic site catalysts play a key role in practical catalysis applications. Herein, we report an amorphous nanobox with high-density atomic platinum species which are uniformly dispersed into the ZIF-8 skeleton through cation exchange. During the dispersing process, the ZIF-8 core was gradually etched into the hollow structure though the Kirkendall effect, and a great amount substitutions of Pt with Zn breaks the initial long-range ordered ZIF-8 topology into a distorted skeleton which leads to the significantly unsaturated coordination of atomic Pt species. The high-density atomic Pt nanoboxes exhibit excellent performance in direct C–H bond borylation of arenes which are usually catalyzed by homogeneous complexes. Such high-density atomic site heterogeneous catalysts could serve as a bridge to convert from homogeneous to heterogeneous catalysis.
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EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
·
2020
·Vol. 2020
·期 25
·3889-3895
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IF 2.889
Xinpeng Jiang,Zongchen Zhao,Zhifeng Shen,Keda Chen,Liyun Fang,Chuanming Yu
Graphical A metal-free aerobic oxidative C–H sulfenylation of aryl-fused cyclic amines with various thiols was developed with excellent functional compatibility. While flavin I catalyzed the C–H sulfenylation of indolines to afford 3-sulfenylindoles, flavin II enabled transformations resulting in substitution at the position para to the N atom on the aryl ring to obtain 6-sulfenylquinolines. We report an aerobic oxidative C–H sulfenylation of aryl-fused cyclic amines with various thiols catalyzed by flavin/I 2 for the first time. While flavin I catalyzed the C–H sulfenylation of indolines to afford 3-sulfenylindoles, flavin II enabled transformations resulted in substitution at the position para to the N atom on the aryl ring to obtain 6-sulfenylquinolines. The advantages of this metal-free oxidative C–S coupling approach utilizing ambient oxygen as the terminal oxidant were that it was conducted under mild conditions with good atom-efficiency and excellent functional compatibility.
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APPLIED ORGANOMETALLIC CHEMISTRY
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2020
·Vol. 34
·期 11
·e5925
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IF 3.14
Jie Yao,Yan Wang,Suleiman Sabo Bello,Guangwen Xu,Lei Shi
As it is well known, Brønsted acid sites in 8-MR of H-MOR (mordenite) are selective for dimethyl ether (DME) carbonylation to methyl acetate, whereas those in 12-MR are more prone to methanol to olefin reaction. Interestingly, we observed that the Brønsted acid sites in 12-MR of H-MOR are highly active for dimethoxymethane (DMM) carbonylation to methyl methoxyacetate (MMAc), whereas those in 8-MR led to the formation of DME. A series of modified H-MOR catalysts with accurate regulation of Brønsted acid sites in 12-MR or 8-MR were successfully synthesized by selective Na + exchange or pyridine (Py) adsorption. Fourier-transform infrared (FT-IR) spectra, NH 3 -temperature-programmed desorption, Py-FT-IR, and inductively coupled plasma analyses suggested that Na + first occupied Brønsted acid sites in 8-MR and then replaced those in 12-MR. All Na + -exchanged catalysts exhibited significant acceleration on MMAc selectivity, and the ratio of Brønsted acid amount in 12-MR/total had a positive correlation with MMAc selectivity. The MMAc selectivity (78%) of H-MOR-0.15Na was nearly 2.5 times more than that of untreated H-MOR (31%). However, H-MOR-Py showed almost no carbonylation activity (<1% MMAc) and a highest DME selectivity (98%), indicating that Brønsted acid sites in 12-MR were the only active sites for DMM carbonylation, whereas those in 8-MR tended to accelerate DMM disproportionation to DME.
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JOURNAL OF SOLID STATE CHEMISTRY
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2026
·
IF 3.2
Zheng-Xuan Ni,Wei Bao,Ming-Yang Shi,Jia-Jia Zhao,Li-Zhuang Chen
H/F substitution drives the coordination reconstruction of Mn 2+ in hybrid chlorides. • Isolated [MnCl 4 ] 2- tetrahedra change to face-sharing [Mn 2 Cl 9 ] 5- units. • The four-to-six coordination change enables green-to-red emission centered at 634 nm. • The fluorinated non-centrosymmetric crystal exhibits phase-transition and piezoelectric responses. Regulation of the Mn 2+ coordination environment is an effective approach for tuning the luminescence of Mn-based hybrid halides. However, the use of H/F substitution on organic cations to regulate the coordination environment of Mn 2+ and thereby tune the emission color remains rarely explored. In this work, H/F substitution was introduced into the piperidinium cation, driving the transformation of Mn-Cl coordination units from four-coordinate to six-coordinate structures and yielding the zero-dimensional hybrid chloride (4-F-Hpip) 5 [Mn 2 Cl 9 ]. This material crystallizes in the chiral non-centrosymmetric P 4 1 2 1 2 space group and contains face-sharing dinuclear [Mn 2 Cl 9 ] 5- units with octahedrally coordinated Mn 2+ . The resulting ligand-field change gives rise to broad red emission centered at 634 nm, while the compound also exhibits a reversible phase transition. In addition, a flexible PBAT composite film containing 10 wt% (4-F-Hpip) 5 [Mn 2 Cl 9 ] generates an open-circuit voltage of approximately 4.9 V. Its luminescent and piezoelectric responses were further integrated into a conceptual dual-input information encryption scheme. This work establishes H/F substitution as an effective cation engineering strategy for regulating Mn 2+ coordination and luminescence in hybrid manganese halides. Download: Download high-res image (198KB) Download: Download full-size image
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ANALYTICAL CHEMISTRY
·
2023
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IF 7.4
Jingjing Zhang,Fenglian Guo,Jingfeng Zhu,Zhimei He,Lin Hao,Lixing Weng,Lianhui Wang,Jie Chao
The development of noninvasive and sensitive detection methods for the early diagnosis and monitoring of bladder cancer is critical but challenging. Herein, an ultrasensitive electrochemiluminescence (ECL) immunosensor that uses Ru(bpy)32+–metal–organic framework (Ru-MOF) nanospheres and a DNA tetrahedral (TDN) probe was established for bladder cancer marker complement factor H-related protein (CFHR1) detection. The synthesized Ru(bpy)32+–metal–organic frameworks (Ru-MOFs) served as a linked substrate for immobilization of AuNPs and antibody (Ab2) to prepare the ECL signal probe (Ru-MOF@AuNPs-Ab2), exhibiting a stable and strengthened ECL emission. At the same time, the inherent advantages of TDN probes on the electrode as the capture probe (TDN-Ab1) improve the accessibility of targets to probes. In the presence of CFHR1, the signal probe Ru-MOF@AuNPs-Ab2 was modified on the electrode through immune binding, thereby obtaining an outstanding ECL signal. As expected, the developed ECL immunosensor exhibited splendid performance for CFHR1 detection in the range of 0.1 fg/mL to 10 pg/mL with a quite low detection limit of 0.069 fg/mL. By using the proposed strategy to detect CFHR1 from urine, it showed acceptable accuracy, which can effectively distinguish between bladder cancer patients and healthy samples. This work contributes to a novel, noninvasive, and accurate method for early clinical diagnosis of bladder cancer.
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PubMed
高影响因子
Catalysis Science & Technology
·
2023
·Vol. 13
·期 15
·4489-4497
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IF 5
Kewu Yang,Ke Wang,Xianfeng Shen,Fanxing Zhang,Bei Huang,Keping Yan,Yao Shi,Yi He,Pengfei Xie
The exposed facets of ceria crystals have a profound effect on the reactivity of ceria-supported catalysts owing to the intricate metal–support interactions. In this work, ceria nanorods, nanocubes, and polyhedra, with corresponding exposed (110)/(100), (100), and (111) terminations, were hydrothermally synthesized to support Pd species, with the aim of investigating the in-depth impacts of ceria crystal facets for methane combustion over ceria-supported palladium catalysts. The nanorod sample delivered the highest methane conversion (T50 = 277 °C, GHSV = 200 000 mL h−1 gcat−1) and greater reaction rate (9.59 × 10−4 molCH4 h−1 gcat−1), 1.23 times that of nanocubes and 3.14 times that of polyhedra. Further characterizations revealed that on the (110)/(100) surface planes, PdOx exhibited stronger interactions with CeO2. This led to enhanced formation of Pd4+ and higher reducibility of PdOx species, thus promoting methane activation. This work would supply experimental insights into the relationship between exposed facets and reactivity, as well as guidance for rational catalyst design.
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WEAR
·
2023
·
IF 5
Yuankai Zhou,Zhiyong Wang,Xue Zuo
Babbitt alloy, the common material of the main bearing of marine diesel engines , is prone to adhesive wear in the running-in process. It will shorten the service life and affect the stability of the bearing. To improve the running-in quality of Babbitt alloy, the hexagonal boron nitride (h-BN) was used as a lubricating oil additive. The running-in test was conducted by adding the h-BN with a particle size of 0.1 μm, 0.5 μm, 1 μm, and 5 μm into the base oil. The friction coefficient , wear topography, and recurrence parameters were used to assess the effect of h-BN on running-in quality. The results show that h-BN can reduce friction coefficient , enhance the stability of the friction system and improve surface quality after the running in. The h-BN with large particle size mainly plays the micro-bearing, interlayer sliding, and polishing effects. The h-BN with small particle size plays the micro-bearing, moderating impact, and surface mending effects. According to the actual conditions, one can select the appropriate particle sizes to improve running-in quality.
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