JOURNAL OF ORGANIC CHEMISTRY
·
2023
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IF 3.6
Jianyu Dong,Shaofeng Wu,Furong Geng,Yani Yan,Long Liu,Yongbo Zhou
A metal-free and selective oxidative methyl C–H functionalization of BHT with aniline compounds has been developed. This innovative method enables the facile and efficient synthesis of a diverse array of BHT-functionalized N-containing skeletons, including arylamines, benzoxazoles, benzothiazoles, benzimidazoles, quinazolines, and quinazolinones, all of which are challenging to access. The control experiment involving TEMP18O suggests that the radical adduct of TEMPO with the benzyl radical of BHT may serve as an intermediate.
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ACS Applied Materials & Interfaces
·
2016
·
IF 7.145
Wei Ji,Guofeng Liu,Zijian Li,Chuanliang Feng
For CH···O hydrogen bonds in assembled structures and the applications, one of the critical issues is how molecular spatial structures affect their interaction modes as well as how to translate the different modes into the macroscopic properties of materials. Herein, coumarin-derived isomeric hydrogelators with different spatial structures are synthesized, where only nitrogen atoms locate at the ortho, meso, or para position in the pyridine ring. The gelators can self-assemble into single crystals and nanofibrous networks through CH···O interactions, which are greatly influenced by nitrogen spatial positions in the pyridine ring, leading to the different self-assembly mechanisms, packing modes, and properties of the nanofibrous networks. Typically, different cell proliferation rates are obtained on the different CH···O bonds driving nanofibrous structures, implying that tiny variation of the stereo-position of nitrogen atoms can be sensitively detected by cells. The study paves a novel way to investigate the influence of isomeric molecular assembly on macroscopic properties and functions of materials.
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APPLIED CATALYSIS B-ENVIRONMENTAL
·
2020
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IF 16.683
Wei Li,Xiao Wang,Qiong Ma,Fei Wang,Xiao-shan Chu,Xue-chuan Wang,Chuan-yi Wang
Solar light driven hydrogen evolution is a prospective strategy to solve the energy problem. However, the poor photoresponse, low photocurrent density and easy electron-hole recombination remarkably restrict the HER activity of the conventional photocatalyst. Herein, we constructed a CdS@hexagonal boron nitride (h-BN) heterostructure on reduced graphene oxide (rGO) to synthesize a ternary CdS@h-BN/rGO catalyst via a structural reconstruction strategy. The CdS@h-BN heterointerface promoted the electrons transferring to the CdS active centers from the valence band of h-BN under photoinduction, overcoming the wide bandgap defect of pristine h-BN. The easily photoexcited property of CdS cocatalyst resulted in superhigh photocurrent density (2.7·μA cm −2 ) under simulated solar light, which was 3.3-fold greater of pristine CdS NPs. Meanwhile, the interfacial interactions of three components remarkably restrained the carriers recombination. Hence, the resultant ternary hybrid catalyst presented remarkably improved photoresponse and interfacial conductivity, thereby the optimal catalyst represented remarkably enhanced HER activity (6465.33 μmol h −1 g −1 ) under simulated solar light, which was about 10.9-fold greater of the pristine CdS NPs and 218.3-fold greater of the optimal h-BN/rGO hybrid. About 19.8 % of apparent quantum yield was achieved under illumination of λ =420 nm, and the excellent regenerability and durability were represented during six cycles and 20 h of continued illumination. Thereby, this study provides a prospective idea for constructing low-cost nonprecious metal based photocatalyst with highly efficient HER performance.
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JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY
·
2019
·Vol. 95
·期 3
·798-805
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IF 2.659
Dan Luo,Shengnan Liu,Wang Yin,Shuqian Xia
BACKGROUND Fast pyrolysis of lignocellulosics has provided an abundant sugar source for production of value-added chemicals, and levoglucosan is the most representative sugar in pyrolysis liquid (bio oil). This paper explored the potential for producing methyl lactate from levoglucosan by employing the mixed catalysts of zeolite tin beta (Sn-Beta) and zeolite hydrogen beta (H-Beta). RESULTS Under the optimal conditions (at 200 °C and mixed catalysts with H-Beta:Sn-Beta ratio of 1:5), the yield of methyl lactate obtained from levoglucosan conversion was as high as 35%. And the yield was comparable to that of methyl lactate obtained from glucose conversion under the similar conditions (at 200 °C and pure Sn-Beta). In order to investigate the reason, a contrasting experiment with glucose as substrate also was carried out with the mixed catalysts. The results indicated that during the levoglucosan conversion process, ‘the methanolysis of levoglucosan’ was likely to compete with ‘the dehydration of glucose’ for the Brønsted acid sites of H-Beta. In addition, the catalytic functions of H-Beta and Sn-Beta, and the reaction pathway were deeply investigated through tracking and comparing the conversion of levoglucosan over mixed H-Beta/Sn-Beta and over pure Sn-Beta catalysts, respectively. CONCLUSION The appropriately lower ratio of H-Beta:Sn-Beta and relatively higher temperature were favorable for the reaction. H-Beta containing Brønsted acid could remarkably accelerate the conversion of levoglucosan and methyl-glucosides to glucose. Sn-Beta containing Lewis acid mainly promoted the retro-aldol condensation of glucose and formation of methyl lactate. © 2019 Society of Chemical Industry
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Science China-Chemistry
·
2023
·Vol. 67
·期 1
·374-382
·
IF 9.6
Luo Zhongfeng,Jiang Jingxing,Zou Lifang,Zhou Xiaoyu,Liu Junshan,Ke Zhuofeng,Chen Fengjuan,Jiang Huanfeng,Zeng Wei
We disclose the development of the Rh-catalyzed amine-directed remote 5,6-carboamination protocol of pyridines via dual Csp 2 –H functionalizations. A variety of readily available 2-aminopyridines and 1,2,3-triazoles are allowed for coupling cyclization to access polyfunctionalized azaindoles. Mechanistic studies including DFT calculations unveil that relay carbenoid-electrophilic addition to pyridines and the sequential pyridyl Csp 2 –H amination are involved in this transformation. The post-synthetic utility of this methodology is showcased by versatile and site-selective modification of azaindoles.
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Frontiers of Chemical Science and Engineering
·
2024
·Vol. 18
·期 11
·1-11
·
IF 4.3
Gao Huimin,Zhang Jinpeng,Zhang Fangyuan,Jing Jieying,Li Wen-Ying
The photocatalytic reduction of CO 2 into formic acid is a feasible approach to alleviate the effects of global climate change and achieve chemical energy storage. It is important to design highly active photocatalysts to improve the selectivity and yield of formic acid. In this study, TiO 2 -based catalysts were prepared and loaded with Pd nanoparticles via an impregnation process. The Pd/H-TiO 2 catalyst demonstrated superior CO 2 reduction activity and a high formic acid production rate of 14.14 mmol cat ·g −1 ·h −1 . The excellent catalytic performance observed in the presence of a Pd/H-TiO 2 catalyst is ascribed to the synergy between O v and Pd. The presence of O v led to increase in CO 2 adsorption while Pd loading enhanced the photogenerated electron-hole pair separation. Electron transfer from H-TiO 2 to Pd also contributed to CO 2 activation.
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JOURNAL OF ORGANOMETALLIC CHEMISTRY
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2023
·
IF 2.3
Run-Ze Yuan,Peng-Fei Cui,Guo-Xin Jin
Herein, we describe the synthesis of a series pincer-type half-sandwich complexes containing selective B(3)-H activation of m -carborane. Four pincer-type complexes containing Cp*M (M = Ir/Rh) and (η 6 -pcym)Ru metal-corner, ionic Cp*M[ m -C 2 B 10 H 9 (CS 2 CH 3 ) 2 ](CF 3 SO 3 ) (M = Ir ( 2 ), Rh ( 3 )), (η 6 -pcym)Ru[ m -C 2 B 10 H 9 (CS 2 CH 3 ) 2 ](CF 3 SO 3 ) ( 4 ) and neutral solvolysis product Cp*Ir[ m -C 2 B 10 H 9 (CS 2 CH 3 )(COS)] (Complex 5 ), have been prepared. The addition reaction of MeO − toward 2 3 and 4 causes the formation of moderately stable neutral unsymmetrical pincer-type complexes Cp*M{ m -C 2 B 10 H 9 (CS 2 CH 3 )[CS(SCH 3 )(OCH 3 )]} (M = Ir ( 6 ), Rh ( 7 )) and (η 6 -pcym)Ru{ m -C 2 B 10 H 9 (CS 2 CH 3 )[CS(SCH 3 )(OCH 3 )]} ( 8 ). The substitution reaction of 2 3 and 4 have also been also explored, unsymmetrical chelate complexes Cp*M( t BuNC)[ m -C 2 B 10 H 9 (CS 2 CH 3 ) 2 ](BPh 4 ) (M = Ir ( 9 ), Rh ( 10 )) can be obtained by using t BuNC and NaBPh 4 . All of these complexes have been characterized, including X-Ray single crystal diffraction, NMR spectroscopy, IR spectroscopy and elemental analysis methods.
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CHEMICAL ENGINEERING JOURNAL
·
2026
·
IF 12.5
Jingxian Wang,Xueyang Liu,Yixuan Lin,Junjie Wang,Hanwen Zhang,Luoxin Wang,Hua Wang,Siwei Xiong
The integration of ceramic fillers with high thermal conductivity into polymer fiber insulating paper enhances both thermal conductivity and dielectric strength. Nonetheless, elevated filler loadings augment the filler-matrix interface, thereby intensifying phonon scattering. Additionally, filler agglomeration, driven by van der Waals forces, impedes the formation of a continuous thermal network and introduces defects that facilitate electrical treeing. This research draws inspiration from “brick-and-mortar” architectures, employing high-surface-area thermotropic liquid crystal polyarylate (PAR) nanofibers as the continuous mortar and surface-modified hexagonal boron nitride (TMS@h-BN) nanoplates as the bricks. A scalable papermaking process is employed to fabricate high-thermal-conductivity insulating paper with a high filler content. The three-dimensional network structure of PAR nanofibers spatially confines the h-BN nanoplates, effectively preventing their agglomeration. Furthermore, π-π conjugation between the aromatic structures of PAR and the benzene rings of h-BN enhances interfacial bonding by facilitating the diffusion and entanglement of PAR molecular chains during thermal pressing. This results in a dense interfacial structure that provides an efficient pathway for phonon transport, thereby enhancing thermal conductivity and minimizing electrical distortion. At a filler loading of 70 wt%, the TMS@h-BN/PAR nanocomposite paper exhibits superior mechanical performance and flexibility, achieving an in-plane thermal conductivity of 14.19 W·m −1 ·K −1 and a breakdown field strength of 111.17 kV/mm, which represent significant improvements over commercial insulating paper. Additionally, it demonstrates exceptional thermal stability and flame retardancy, with minimal dimensional changes following heat treatment.
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FUEL
·
2023
·
IF 7.4
Muhammad Yousaf,Yuzheng Lu,Majid Niaz Akhtar,Ali Sarosh Khawaja,Khalid Mujasam Batoo,Sajjad Hussain,Asma Noor,Muhammad Akbar,Hu Enyi,M.A.K Yousaf Shah,Naveed Mushtaq,Bin Zhu
Lattice defects in rare earth (RE) doped single-phase semiconductor materials play a key role in structural modifications and physicochemical characteristics, resulting to enhance the ionic conductivity. In this work, we synthesized lanthanum doped samarium oxide with different mole ratios and applied it as a ceramics membrane fuel cell device to enable high peak power density (PPD) at low operational temperatures (520–400 °C). The samples are capable of triple charge H + /O 2− /e − conduction and enhance the catalytic function of the cell in terms of HOR and ORR kinetics by producing lattice defects. The fabricated Sm 1.5 La 1.5 Fe 5 O 12 (2-SLFO) fuel cell device exhibits a high OCV of 1.13 V with a maximum PPD of 864.26 mW/cm 2 at 520 °C. Durability measurement verifies that 2-SLFO-based fuel cell device can be worked for 60 h under fuel cell conditions (H 2 /air) at 520 °C. The first principle calculations using density functional theory (DFT) demonstrate that the higher oxygen vacancy concentration in the 2-SLFO sample may cause to the higher charge-transfer kinetics, subsequent in the enhancement of ions transportation of the fabricated fuel cell device.
研究领域:
材料科学
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电化学
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能源材料
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固态离子学
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燃料电池技术
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JOURNAL OF ALLOYS AND COMPOUNDS
·
2024
·
IF 5.8
Chia-Tse Lee,Haoyuan Zheng,Chen Jin,Hang Che,Li Wang,Yuyuan Zhao,Shixuan He,Xinhua Wang,Yifeng Yu,Mi Yan
Metal nitrogen hydride (Li-Mg-N-H) is regarded as an ideal hydrogen storage material for automotive applications due to its advantages of high hydrogen storage capacity (5.6 wt%), low operating temperature, and good cycling performance, but the comprehensive hydrogen storage performance of this material still could be improved. For this reason, this paper constructed a Li-Na-Mg-N-H composite system by synthesizing NaMgH 3 to replace MgH 2 in the Li-Mg-N-H system. The improvement of the hydrogen absorption and desorption properties of the composite system after the replacement of MgH 2 by NaMgH 3 was investigated. Various properties and test results showed that the composite system after the replacement of MgH 2 by NaMgH 3 showed better hydrogen absorption and desorption properties. The initial/peak hydrogen release temperatures of Li-Na-Mg-N-H decreased from 135 ˚C/245 ˚C to 105 ˚C/145 ˚C, and the apparent activation energy of hydrogen release was reduced from 114.90 to 104.05 kJ/mol which means the kinetics of hydrogen absorption and desorption was greatly improved. The mechanism study shows that NaMgH 3 will react with LiNH 2 and forms the intermediate product Li 3 Na(NH 2 ) 4 during the hydrogen release process, which changes the hydrogen desorption pathway of the composite system and thus the hydrogen absorption and desorption kinetics were improved.
研究领域:
材料科学
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氢气储存
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能源材料
·
固态化学
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IONICS
·
2025
·
IF 2.6
Yong Daming,Kang Xiaomeng,Yin Ming,Wu Qichao
First, a spherical Fe 3 O 4 was synthesized using the hydrothermal method, and subsequently coated with carbon to form a core–shell C/Fe 3 O 4 composite. The Fe 3 O 4 core was then dissolved in an etching solution to create a hollow carbon (H-C) structure. This H-C served as a substrate onto which a Fe 3 O 4 layer was deposited via the hydrothermal method, resulting in a hollow core–shell Fe 3 O 4 /C composite. Finally, the solvothermal method was employed to coat the Fe 3 O 4 /C composite with a layer of hydrogenated titanium dioxide (H-TiO 2 ), resulting in a hollow-structured H-TiO 2 /Fe 3 O 4 /C material. This structure not only ensures the formation of a dual-core shell structure, but also reduces the proportion of carbon material in the composite electrode, thereby enhancing the theoretical specific capacity of the composite electrode. The presence of H-TiO 2 and carbon improved the cyclic stability of Fe 3 O 4 within the composite. This hollow sandwich–structured composite demonstrated excellent electrochemical performance, delivering a discharge specific capacity of 629.5 mAh g −1 after 500 cycles at 0.2 A g −1 , along with a high initial coulombic efficiency of 80.6%.
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ENVIRONMENTAL POLLUTION
·
2022
·
IF 9.988
Jijie Kong,Xiaoyu Cao,Wen Huang,Chao Li,Qiming Xian,Shaogui Yang,Shiyin Li,Cheng Sun,Huan He
The occurrence of nitrated polycyclic aromatic hydrocarbons (NPAHs) in sediments has been widely reported, but research on NPAH bioavailability is lacking. In this study, a self-made zeolite imidazolate framework-8/hexagonal boron nitride (ZIF-8/h-BN) solid-phase microextraction (SPME) fiber and commercial Tenax are compared as efficient tools to predict the bioavailability of NPAHs in sediments with bioassays using Cipangopaludina chinensis . During the process of SPME, the NPAH concentrations on the ZIF-8/h-BN fibers reached extraction equilibrium after 72 h. The fiber extraction of NPAHs in sediments was well-fitted by the pseudo first-order kinetic model with a rate constant of 2 × 10 −2 h −1 (R 2 > 0.98). The extraction rates ranking of NPAHs in sediments was 2-nitrobiphenyl>1-nitropyrene>5-nitroacenaphthene>2-nitrofluorene. Compared with SPME, NPAH concentrations reached equilibrium after 168 h for the Tenax extraction. The orders of magnitude of fast, slow, and very slow desorption rate constants were 10 −1 , 10 −2 , and 10 −4 , respectively. At extraction equilibrium (168 h), the SPME was close to the bioavailability of the NPAHs in sediments to Cipangopaludina chinensis with a slope statistically approximated to one. In addition, the linear regression for SPME (R 2 = 0.7285) was slightly higher than that of the Tenax extraction (R 2 = 0.7168) over a short time (6 h). This could be because the coating material of ZIF-8/h-BN can rapidly adsorb freely dissolved NPAHs, and the SPME fibers can accurately predict the bioaccumulated concentrations of NPAHs in exposed organisms by measuring the concentration of NPAHs in the pore water of sediment. This study provides a time-saving and easy procedure to predict the bioavailability of NPAHs in sediments.
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