EUROPEAN JOURNAL OF ORGANIC CHEMISTRY
·
2024
·
IF 2.5
Fumeng Yin,Shan Hu,Shuwei Zhu,Shifeng Xing,Hongjun Zhu
Graphical Using mesoporous graphitic carbon nitride (mpg-C 3 N 4 ) as a metal-free heterogeneous photocatalyst was developed for thiocyanation of alkenes under visible light irradiation with oxygen as green oxidant and without any other additives. The present protocol has excellent functional group tolerance and the desired tetrasubstituted alkenyl thiocyanides were obtained in moderate to good yields. Moreover, the recyclable mpg-C 3 N 4 catalyst could be used at least 6 times without significant loss of activities. Using mesoporous graphite carbon nitride (mpg-C 3 N 4 ) as metal-free heterogeneous catalyst, the thiocyanation of ketene dithioacetals was achieved under visible light irradiation with oxygen as green oxidant and without any other additives. The present protocol has excellent functional group tolerance and the desired tetrasubstituted alkenyl thiocyanides were obtained in moderate to good yields. Moreover, the recyclable mpg-C 3 N 4 catalyst could be used at least 6 times without significant loss of activities. A series of mechanistic validation experiments indicated that the reaction involves a radical process.
研究领域:
有机化学
·
催化化学
✓ 已验证
DOI
高影响因子
Research
·
2020
·
IF 0
Jiapeng Ji,Ying Sha,Zeheng Li,Xuehui Gao,Teng Zhang,Shiyu Zhou,Tong Qiu,Shaodong Zhou,Liang Zhang,Min Ling,Yanglong Hou,Chengdu Liang
The shuttle effect hinders the practical application of lithium-sulfur (Li-S) batteries due to the poor affinity between a substrate and Li polysulfides (LiPSs) and the sluggish transition of soluble LiPSs to insoluble Li2S or elemental S. Here, we report that Ni hexatomic clusters embedded in a nitrogen-doped three-dimensional (3D) graphene framework (Ni-N/G) possess stronger interaction with soluble polysulfides than that with insoluble polysulfides. The synthetic electrocatalyst deployed in the sulfur cathode plays a multifunctional role: (i) selectively adsorbing the polysulfides dissolved in the electrolyte, (ii) expediting the sluggish liquid-solid phase transformations at the active sites as electrocatalysts, and (iii) accelerating the kinetics of the electrochemical reaction of multielectron sulfur, thereby inhibiting the dissolution of LiPSs. The constructed S@Ni-N/G cathode delivers an areal capacity of 9.43 mAh cm-2 at 0.1 C at S loading of 6.8 mg cm-2, and it exhibits a gravimetric capacity of 1104 mAh g-1 with a capacity fading rate of 0.045% per cycle over 50 cycles at 0.2 C at S loading of 2.0 mg cm-2. This work opens a rational approach to achieve the selective adsorption and expediting of polysulfide transition for the performance enhancement of Li-S batteries.
研究领域:
材料科学
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能源化学
·
电化学
✓ 已验证
DOI
MATERIALS LETTERS
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2014
·
IF 2.269
Yu Zou,Jiang Jiang
We report the colloidal synthesis of monodisperse phase pure chalcostibite CuSbS 2 nanocrystals in high boiling point solvent. The use of dodecanethiol as ligands had an advantage over oleylamine on avoiding the hydrolysis of Sb precursor. The effect of reaction temperature and Cu/Sb feed molar ratio on the synthesis of copper antimony sulfide nanocrystals in dodecanethiol system was investigated. As a result of the reactivity difference between Cu and Sb precursors, the formation of CuSbS 2 nanocrystals involves the preferential nucleation of Cu-rich nanocrystals and their subsequent reaction with remaining Sb precursors. The band gap of the resulting CuSbS 2 nanocrystals was measured to be ~1.59 eV.
研究领域:
材料化学
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纳米科学
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无机化学
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半导体材料
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胶体化学
✓ 已验证
DOI
高影响因子
ELECTROCHIMICA ACTA
·
2015
·
IF 4.504
Xiaogang Li,Mumin Rao,Dongrui Chen,Haibin Lin,Yanlin Liu,Youhao Liao,Lidan Xing,Weishan Li
We report a novel composite, sulfur supported by multi-walled carbon nanotubes and coated with polyaniline (denoted as MWCNTs-S@PANI), as cathode of lithium-sulfur battery. MWCNTs-S is prepared by loading sulfur on MWCNTs via chemical deposition and coated with polyaniline via in situ polymerization under the control of ascorbic acid. The physical and electrochemical performances of the resulting MWCNTs-S@PANI are investigated by nitrogen adsorption-desorption isotherms, X-ray powder diffraction, thermogravimetric analysis, scanning electron microscopy, transmission electron microscopy, electrochemical impedance spectroscopy, and charge/discharge test. It is found that MWCNTs-S@PANI exhibits good cyclic stability and rate capability compared to MWCNTs-S as cathode of lithium-sulfur battery.
研究领域:
电化学
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材料科学
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能源存储
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纳米材料
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电池技术
✓ 已验证
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE
·
2018
·Vol. 53
·期 15
·11062-11077
·
IF 2.993
Xue Mingzhe,Chen Chen,Tan Yan,Ren Zhiwei,Li Bing,Zhang Cunman
Porous carbon with various structures from micropores (< 2 nm) to hierarchical pores (0–4 nm) was synthesized from biomass waste mangosteen peels via KOH activation process. Microporous carbon was obtained mainly at a low activation temperature of 700 °C or a low alkali/carbon of 3. Hierarchical porous carbon with ultrahigh surface area (> 3000 m 2 g −1 ) and pore volume (> 1.4 cm 3 g −1 ) was obtained at alkali/carbon ratio higher than 3.5 and activation temperature of 800 °C. Sulfur with a high content of 65 wt% was able to be fully accommodated into the pores of hierarchical porous carbon to form C/S composite cathode for lithium sulfur battery while in the case of microporous carbon, residual sulfur on carbon surface was detected. High specific discharge capacities of more than 800 mAh g −1 were achieved from hierarchical porous carbon/S composites at 0.5 C, and the sample synthesized at alkali/carbon of 4 and activation of 800 °C exhibits the best cycling performance. After 500 cycles at 0.5 C, a high discharge capacity of 509 mAh g −1 was maintained, indicating an excellent capacity retention. Relationship between pore characteristics of porous carbon and the electrochemical performance of its sulfur composite was discussed.
研究领域:
材料科学
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电化学
·
能源存储
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纳米材料
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可持续材料
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电池技术
✓ 已验证
DOI
高影响因子
Batteries & Supercaps
·
2020
·Vol. 3
·期 9
·892-899
·
IF 0
Wantang Li,Yifang Zhang,Huan Li,Zijin Chen,Tongxin Shang,Zhitan Wu,Chen Zhang,Jia Li,Wei Lv,Ying Tao,Quan-Hong Yang
The shuttle effect of lithium polysulfides (LiPSs) from sulfur cathode to lithium (Li) anode is one of the main obstacles for lithium-sulfur (Li−S) batteries. The severe corrosion of Li metal anode by the dissolved LiPSs bottlenecks the efficient operation of Li−S batteries, however, the anode part has not been received much attention compared to those extensive efforts related to the cathode designs. Herein, we show that the interface between Ti 3 C 2 T x (T=−OH, −F)-based MXene and reduced graphene oxide (rGO) is able to guide uniform Li nucleation, promoting highly reversible and dendrite-free Li plating/stripping. Such the Li anode demonstrates excellent cycling stability for more than 1000 hours even under ultra-high rate (10 mA cm −2 ) and high areal capacity (3 mAh cm −2 ). More importantly, the well-designed 2D layered structure by coupling the Ti 3 C 2 T x with a graphene scaffold, is highly efficient to block the shuttled polysulfides and inhibit the corrosion of the lithium metal anode. As a result, the Li−S full battery exhibits a stable cycling stability with a high Coulombic efficiency of 99.8 % over 300 cycles. This work suggests the design strategy of Li metal anode especially targeting at the sulfur cathode, and we hope it can provide valuable inspirations for the future design of Li metal anodes for more practical Li−S batteries. Graphical MXene shield : The rGO/Ti 3 C 2 T x interfaces favor Li nucleation and deposition, contributing to dendrite-free Li plating/stripping behaviors inside the scaffold. The membrane also mitigates the side reactions of Li by blocking the shuttled lithium polysulfides, which promotes the efficient cycling of Li−S batteries.
研究领域:
材料科学
·
电化学
·
能源存储
·
纳米材料
·
电池技术
✓ 已验证
DOI
MINERALS ENGINEERING
·
2018
·
IF 2.707
Wencui Chai,Yanfang Huang,Weijun Peng,Guihong Han,Yijun Cao,Jiongtian Liu
The existence of sulfide minerals (mainly pyrite) limits the use of high-sulfur bauxite in the production of Bayer alumina. In this work, the reverse flotation desulfurization using 2-mercaptobenzimidazole (MBI) as the collector was studied by L 9 (3 4 ) orthogonal tests. The interaction mechanisms of MBI with pyrite were investigated by advanced analysis technologies including scanning electron microscopy, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), contact angle testing and zeta potential analysis. Results indicate that the sulfur content of bauxite is decreased from 2.87% to 0.26% by one roughing and one cleaning flotation under the optimized conditions of collector dosage of 100 g/t, activator dosage of 60 g/t, frother dosage of 200 g/t and pulp pH at 3. MBI exhibits superior hydrophobic behavior on the pyrite surface under the acid solution than under the alkaline solution, which favors the flotation of pyrite under the acidic condition. The zeta potential, FTIR and XPS results reveal that the interaction mechanisms of MBI with pyrite are electrostatic forces and chelation by forming N Fe S coordination bonds. MBI is an efficient collector of pyrite in the flotation desulfurization of high-sulfur bauxite and is expected to be used in other oxide or sulfide ores to separate pyrite.
研究领域:
矿物加工工程
·
冶金工程
·
表面化学
·
资源综合利用
·
浮选化学
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2018
·
IF 6.735
Mantang Chen,Zhimin Zhang,Lihua Zhu,Nan Wang,Heqing Tang
The present work aimed at using bisulfites (HSO 3 − ) to enhance the oxidative degradation of bisphenol A (BPA) in a Fenton process based on the Fe 3+ -H 2 O 2 reagents. It was confirmed that both the degradation and mineralization of BPA were drastically enhanced by the addition of HSO 3 − . Typically, the use of 0.1 mmol L −1 Fe 3+ , 0.3 mmol L −1 HSO 3 − and 10 mmol L −1 H 2 O 2 achieved a complete degradation of BPA (0.05 mmol L −1 ) in only 2 min. The addition of HSO 3 − increased the BPA degradation rate constant from 0.045 min −1 in the Fe 3+ -H 2 O 2 system to 2.71 min −1 in the Fe 3+ -HSO 3 − -H 2 O 2 system by 60 times. This drastic enhancement effect of HSO 3 − was attributed to its complexing and reducing abilities. The formation of FeSO 3 + complex prevented the precipitation of Fe 3+ and accelerated the cycling of Fe 3+ /Fe 2+ ; the reducing ability of HSO 3 − further favored the transformation of Fe 3+ to Fe 2+ . Several reactive species, including OH, SO 3 − and SO 4 − were responsible for the degradation of BPA, among which OH was the dominant one. The proposed Fe 3+ -HSO 3 − -H 2 O 2 system is suggested be able to act as the followed stage of a traditional Fe 2+ -H 2 O 2 system in the engineering setting.
研究领域:
环境科学
·
化学工程
·
污染控制
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2018
·
IF 3.057
Jinghui Zhu,Rosaiah Pitcheri,Tuo Kang,Ya Guo,Jing Li,Yejun Qiu
Shuttle effect of the dissolved polysulfide is a main disadvantage for Li-S batteries, which has been explored by several polar materials to absorb lithium polysulfide with physical and chemical effect. Herein, for the first time, a composite of carbon nanofibers decorated with MnO nanoparticles (CNF-MnO) has been prepared by the facile electrospinning method followed by thermal treatment. SEM and TEM characterization delivered that the MnO NPs on CNF did not change the morphology but decrease the electronic conductivity of CNF-MnO composite. The CNF-MnO composite exhibited excellent electrochemical cyclic stability because of its strong chemical absorption for polysulfide. Interestingly, CNF-MnO composite served as both cathode as well interlayer for Li-S batteries. The CNF-MnO-S as cathode material showed an initial discharge capacity of 683.2 mAh g -1 at 1.0 C and remained 592.0 mAh g -1 even after 250 cycles with the capacity decay of 0.053% per cycle. As well, CNF-MnO as interlayer delivered superior cycling stability even at high current density of 3.0 C, where the capacity still maintained 542.2 mAh g -1 over 200 cycles.
研究领域:
材料科学
·
能源存储
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2018
·
IF 6.735
Lei Wang,Deren Fang,Yisen Wang,Hui Tian,Jie Liu,Wanzhong Ren
For fluid catalytic cracking naphtha, there exists a complex co-existing gas–liquid-solid three-phase system in the catalyst bed under deep hydrodesulfurization (HDS) conditions representative of industrial practice. The system is extremely crucial and could influence and even determine the finished HDS reaction result. The paper reports that owing to the diffusion at the gas/liquid interface of the above system, thiophene rather than slow-reacting benzothiophene and its alkylated derivatives remains in the final product, which is against with common-sense knowledge about the relative reactivity of sulfur compounds. Two designed experiments which investigate impacts of solvents and sulfur-containing compounds under different temperatures further corroborate the above conclusion. Meanwhile, they reveal that elimination of the diffusion through making gas/liquid two phases into one gas or liquid phase effectively improves the efficiency of desulfurization even under the same reaction conditions. It could be concluded that for the deep HDS reaction, diffusion at the gas/liquid interface is the rate-determining step of whole reaction, which is also proved by the resulting data under conditions (production of Euro-5 gasoline).
研究领域:
化学工程
·
石油加工
·
催化反应
✓ 已验证
DOI
高影响因子
ATMOSPHERIC ENVIRONMENT
·
2024
·
IF 4.2
Chunyan Zhang,Qingxin Ma,Peng Zhang,Tianzeng Chen,Yonghong Wang,Biwu Chu,Hao Li,Jikun Li,Chuncheng Chen,Jincai Zhao,Hong He
As the main source of atmospheric sulfate aerosol , the aqueous-phase oxidation of SO 2 has been of great concern. Traditionally, the aqueous-phase oxidation of SO 2 is considered a consumption process of atmospheric oxidation capacity; however, we report here that •OH radicals and other reactive oxygen species (ROS) can be generated in the photochemical reactions of bulk HSO 3 − solution. This •OH production pathway results in the fast sulfate formation in the photooxidation of dissolved SO 2 . The photochemical process is determined to be pH-dependent in which sulfate formation is promoted by decreasing pH. Hence, a light - driven acidic positive feedback mechanism is proposed that the oxidation of dissolved SO 2 and the formation of •OH radicals have a synergistic promoting effect. These results indicate that the photochemistry of dissolved SO 2 could be a missing source of aqueous •OH radicals as well as sulfate at regional to global scales.
研究领域:
大气科学
·
环境化学
✓ 已验证
DOI
高影响因子
ELECTROCHIMICA ACTA
·
2017
·
IF 4.798
Zhenhua Wang,Xiaodong Wang,Wang Sun,Kening Sun
Lithium sulfur (Li-S) batteries are highly prospective for future generations of transportation and grid storage due to their high energy density and low cost. However, the Li dendrite growth from the anode and the “polysulfide shuttle” from the cathode may cause poor cycling performance and safety concerns, hindering the practicality of Li-S batteries. Herein, we demonstrate a novel separator design by coating three-dimensional (3D) carbon nanofiber (CNF) interlayers on both sides of the separator to achieve a high performance Li-S battery. The CNF interlayer can not only render a uniform Li deposition on the anode by eliminating the “tip effect”, but also restrain the polysulfide diffusion on the cathode with its porous and highly conductive 3D architecture, enhancing the utilization of S-related species significantly. So an average Coulombic efficiency of the Li metal anode protected by a CNF interlayer is up to 95% for 100 cycles at 0.5 mA cm −2 . Moreover, Li-S batteries with CNF interlayers can exhibit remarkable cycle performance, presenting an initial specific capacity of 1207.4 mAh g −1 at 0.5C and retaining at 828.1 mAh g −1 after 100 cycles. In addition, the low-cost raw materials and the simple preparation for CNF interlayers is suitable for industrial scale-up.
研究领域:
材料科学
·
能源存储技术
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）