PROGRESS IN REACTION KINETICS AND MECHANISM
·
2017
·
IF 0.682
Hua Song,Shengnan Li,Hualin Song,Feng Li,Huapeng Cui
A number of Zn–S2O82–/ZrO2–Al2O3 (Zn(x)–SZA) catalysts with different Zn mass fractions were synthesised and characterised by using X-ray diffraction, the Brunauer–Emmett–Teller method, and H2 temperature-programmed reduction. The structure and isomerisation performance of Zn(x)–SZA catalysts were studied using n-pentane as a probe reaction. The results showed that a pure tetragonal ZrO2 phase was formed on Zn(x)–SZA, and the ZrO2 crystallite sizes of the tetragonal phase increased in the order: Zn(0.5)–SZA < Zn(1.0)–SZA < Zn(1.5)–SZA < Zn(2.0)–SZA < SZA. Zn can strengthen the interaction between persulfate ions and the support, promote the formation of stronger acidity, lead to a better dispersion of sulfate ions on the surface, and improve the redox performance of the catalysts. The Zn(1.0)–SZA catalyst exhibited the best catalytic activity for n-pentane isomerisation. At a temperature of 170 °C, a reaction pressure of 2.0 MPa, a molar H2/n-pentane ratio of 4:1, and a weight hourly space velocity of 1.0 h−1, the isopentane yield reached 58.0%.
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CHEMICAL PHYSICS
·
2020
·
IF 1.771
Shenghai Zhou,Hongbo Xu,Jinyu Liu,Yajun Wei,Xinhuan Ma,Zhimin Han,Hongli Chen
N-doped carbon nanopipe-arrayed mesoporous carbon (N-CMK-5) with double-pore system, large surface area (992 m 2 /g), and high nitrogen amount (5.2 at.%) was synthesized by a simplified template route. In this route, mesoporous silica was directly used instead of using time-consuming aluminosilicate as a template and the carbonization process occurred in a nitrogen atmosphere instead of a vacuum. Furthermore, CMK-3, N-doped CMK-3, and CMK-5 ordered mesoporous carbons (OMCs) were compared with the as-prepared N-doped CMK-5 (N-CMK-5) to investigate the effect of microstructure on the electrochemical activity of OMCs. N-CMK-5 exhibited higher electrochemical activity than the other OMCs because it has more exposed defective sites and nitrogen active species. The developed N-CMK-5-based electrochemical sensor showed good practical application for the electrochemical detection of pesticide amitrole in real water sample. This work contributes a simplified route to synthesize tubular N-CMK-5 carbon and provides valuable information on the design of high-performance carbon electrode materials.
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JOURNAL OF MEMBRANE SCIENCE
·
2019
·
IF 7.015
Heng Mao,Shen-Hui Li,Ao-Shuai Zhang,Li-Hao Xu,Jiao-Jiao Lu,Zhi-Ping Zhao
With the help of density functional theory calculations, a unique MOF-capped nanotube architecture was initially conceived in this study based on the solution-diffusion mechanism. Then, the novel ZIF-8-capped halloysite nanotubes (ZHNTs) were prepared and incorporated in the polydimethylsiloxane (PDMS) bulk to achieve the mixed matrix membranes (MMMs) for n -butanol permselective pervaporation . The remarkable characteristic of this membrane was that the HNT lumen (∼25 nm) in ZHNTs provided the exquisite diffusion highway for the penetrants that were first selected through the capping ZIF-8 layer. Simultaneously, the close connection of ZIF-8 layer on external surface of ZHNTs created the relatively continuous pathways for molecular permeation. As expected, the embedding ZHNTs significantly improved the separation performances of the membranes. Impressively, the as-obtained membrane acquired a high separation factor of 61.3 (58.7% higher than that of PDMS control membrane) with a comparable flux of 683 g m -2 h -1 (2.43-fold as much as that of PDMS control membrane) at 40 °C in the separation of 1 wt% n -butanol aqueous solution. Moreover, the presence of ZHNTs conferred excellent interfacial compatibility, mechanical properties, and good long-term stability on the resultant membranes. This study may shed light on the rational design of high-performance MMMs for biofuels recovery from fermentation broths .
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ELECTROCHIMICA ACTA
·
2016
·
IF 4.803
Yujing Sun,Zhicai Xing,Shu Jiang,Hexin Zhang,Gang Wei,Zhuang Li,Xuequan Zhang
We demonstrated here the crosslinked N-doped graphene (NG) can be rapidly prepared through a one-step burning process of graphene oxide . The doping process completed within 3 minutes and the N content in the obtained NG reached to 5.6%. The obtained crosslinked NG shows mesoporous structure with relatively high specific area, large pore volume and various N types. As a supercapacitor , the resultant NG exhibits rapid diffusion of electrolyte ions and shows superior capacitive performance, excellent specific capacitance (317.5 F/g at the current density of 1 A/g) and high cycling stability (93% retention after 5000 cycles). The obtained results indicate that the crosslinked NG is a promising candidate for creating supercapacitors with high performance and relatively low cost.
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高影响因子
ENVIRONMENTAL TECHNOLOGY
·
2021
·
IF 3.247
Yangyang Wang,Qiang Ren,Wenhao Zhan,Kaixuan Zheng,Qi Liao,Zhihui Yang,Yansong Wang,Xinling Ruan
A previous isolated Gordonia sp. (Lff) was used to degrade di-n-octyl phthalate (DOP) contamination in both aqueous solution and soil. The influence of temperature, pH, inoculum size, salt content and initial concentration of DOP on DOP degradation by Lff were analysed. The response of soil bacterial community to DOP and Lff was also analysed by Illumina MiSeq sequence method. Results showed that the optimal temperature, pH, inoculum size and salt content were 35oC, 8.0, 5% and <5%, respectively. Under the optimal condition, more than 91.25% of DOP with different initial concentrations (100–2000 mg/L) could be degraded by Lff. Kinetics analysis indicated that biodegradation of DOP by Lff could be described by first-order kinetics (R2 > 0.917) with the half-life (t1/2) changing irregularly between 0.58 and 0.83 d. In addition, Lff enhanced the removal of DOP in soil and alleviated the toxicity of DOP on soil microorganisms. Furthermore, its influence on soil bacterial community is not obvious. These results suggested that Lff was effective in remediating DOP contamination in different environments.
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NEW JOURNAL OF CHEMISTRY
·
2024
·Vol. 49
·期 1
·132-140
·
IF 2.7
Rumeng Feng,Lu Chen,Liping Huang,Haihong Wu,Yuanyu Ge,Jiani Xu,Min Zeng,Wenyao Li
The synergistic effect between the transition metal sulfide alloy core, the N-doped graphene shell, and the internal interfacial potential serves to regulate the electronic structure and facilitate electron transfer. We used Fe-based Prussian blue analogues as a single precursor to prepare a N-doped graphene-coated metal core–shell structure (FeNi@NG) through hydrothermal and high-temperature solid phase reactions. The S source was then introduced and annealed, yielding a S, N co-doped graphene-encapsulated metal core–shell structure (FeNi–S@NG). Finally, a nitrogen-doped graphene-coated metal core–shell structure with S defects (S–FeNi@NG) was obtained through NaBH4 liquid-phase reduction. The synergistic effect between the transition metal sulfide alloy core and the N-doped graphene shell, in conjunction with the internal interfacial potential regulate the electronic structure and facilitate electron transfer. Numerous sulfur vacancies accelerate electron transfer and enhance OER catalytic performance. The optimized material, S–FeNi@NG, exhibited excellent OER catalytic performance, with an overpotential of 250 mV (at 10 mA cm−2) and a Tafel slope of 90.95 mV dec−1 in an alkaline electrolyte.
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SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Yu Wang,Ruoyu Hu,Wenli Liu,Zhaoyou Zhu,Yinglong Wang,Jingwei Yang,Jianguang Qi,Peizhe Cui
In the process of producing low-carbon alcohols from coal, azeotropic waste containing ethanol and n-hexane is generated. To prevent environmental risks and resource waste from solvent loss, this study selected green solvent ionic liquids (ILs) for their separation. First, we screened five anions with high selectivity based on the conductor-like screening model for realistic solvents (COSMO-RS), and through various quantum chemical calculations, we found that the anions play a significant role in the separation of the two components, with [HSO 4 ] − showing the best separation performance. Second, we predicted the phase equilibrium data for ILs containing [HSO 4 ] − in the azeotropic system, considering practical factors such as price and viscosity, and selected [EMIM][HSO 4 ], [BMIM][HSO 4 ], and [HMIM][HSO 4 ] for experiments. The results indicated that simpler cation side chains enhance the separation capability of the system. Then, a toxicity analysis of the ILs ensured their biocompatibility and feasibility. Finally, we established the extraction distillation process and visualized the interactions between the ILs and the azeotropic system through molecular dynamics simulations. This work provides theoretical guidance for the separation of alcohols and alkanes in the industry.
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NANOTECHNOLOGY
·
2019
·Vol. 30
·期 30
·305402
·
IF 3.399
Tong Wu,Yaying Li,Yuntong Li,Jing Hong,Haiyang Wu,Jie Mao,Yuzhe Wu,Qipeng Cai,Conghui Yuan,Lizong Dai
Simultaneous introduction of both transition metal and other inorganic elements into the carbon matrix has attracted great attention in the fabrication of carbon materials with high electrochemical properties. Herein, rational design of ligand-iron coordinative supramolecular precursors is achieved for the fabrication of Fe-N/C catalysts, which possess high oxygen reduction reaction (ORR) performance. A series of precursors are prepared by a simple coordination reaction between a three armed catechol monomer and iron ions. Particular interest is focused on tuning the doping species, surface area and morphology of the Fe-N/C catalysts through a simple selection of iron resources. We show that an Fe-N/C catalyst derived from Fe2(SO4)3 at a carbonization temperature of 800 °C, has the optimized ORR performance with an onset potential of 0.930 V and half-wave potential of 0.801 V. Detailed investigation indicates that the synergistic effect among doping elements of nitrogen and sulfur and the unique carbon structure determines the performance of the Fe-N/C catalysts. Our findings may be of significance for the fabrication of doped carbon materials using coordinative supramolecular polymers as precursors.
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CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Qian Yu,Jingshu Wang,Haibo Li,Ruiqing Li,Suyuan Zeng,Rui Li,Qingxia Yao,Hongyan Chen,Konggang Qu,Yao Zheng
In the electrocatalytic oxygen reduction and hydrogen evolution reactions (ORR/HER), metal-free carbon-based materials presented great potentials as alternatives to Pt because of their flexible adjustability of electronic and geometric properties. The pursuit of high-performance carbons demand for high-level doping, large surface area and high graphitization, but the improvement of the former two aspects would inevitably impair the third one, which seems a contradictive proposition. Herein, by a facile “mix-and-pyrolyze” method, natural DNA was first developed to synthesize N, P, S-tridoped carbons (NPSC) with porous sheet structures, high graphitization, large surface areas and abundant high-quality dopants simultaneously. Thus, the newly-prepared NPSC displays superior alkaline ORR performance comparable to Pt/C together with excellent acidic activity and better stability. Meanwhile, NPSC is one of most active acidic HER catalysts and the best alkaline HER catalyst among carbon counterparts. Density function theory computation reveled the origins of superior performance are attributed to positively charged C sites neighboring to S for ORR and P sites for HER because of DNA-derived advantaged structural features. The as-fabricated rechargeable zinc–air battery based on current tridoped carbon has closed peak power density and specific capacity but much better charge–discharge stability compared with Pt/C.
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Journal of Material Cycles and Waste Management
·
2023
·Vol. 25
·期 4
·2485-2497
·
IF 3.1
Wei Jie,Liu Zhanwei,Yan Hengwei,Yang Wanzhang
Herein, fluorine fixation, nitrogen removal, and the alkaline solution recovery of alumina were studied using calcium-based high-temperature soda roasting. In addition, the effects of roasting conditions, dissolution conditions, and additives (carbon alkali and calcium salt) on fluorine fixation and alumina recovery were studied. The results show that when the roasting temperature was 1100 ℃ and the roasting time was 2 h, the dissolution temperature was 80 °C, while the dissolution time was 20 min. The ratio of soda to dross was 1.0, and 30 wt% CaCO 3 had been added as a fluorine fixing agent. The Al extraction rate from aluminum dross (AD) reached 86.21%, the denitrification rate reached 99.54%, the concentration of soluble fluoride ion was reduced to 0.111 g·L −1 , and the fluoride fixation rate was 75.04 wt%. CaF 2 is the main component of the leaching residue, which can be added as an insulation material for electrolysis. Alkaline oxidation roasting and calcium-based fluoride fixation are effective methods to separate aluminum, fluoride, and nitrogen. This study provides a new method for the safe and efficient utilization of AD.
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JOURNAL OF ALLOYS AND COMPOUNDS
·
2022
·
IF 6.371
Sijun Yang,Jie Yu,Chengli Yao,Shikuo Li,Anjian Xie
The development of efficient non-precious-metal catalysts for oxygen reduction reaction (ORR) is greatly important for accelerating the commercial application of fuel cells. Herein, polystyrene (PS) nanospheres are used as templates for the growth of zeolitic imidazolate framework (ZIF) complex precursors with variable molar ratios of Fe 3+ to Zn 2+ in situ. Through carbonization at a high temperature, the hierarchical porous carbon (HPC) materials with different proportions (xFeyZn-HPC, x + y = 100) have been prepared. The typical product 5Fe95Zn-HPC is composed of nitrogen (N)-doped hierarchical porous carbon loaded with Fe/Fe 5 C 2 nanoparticles obtained at optimal molar ratio. As an electrocatalyst, the 5Fe95Zn-HPC shows a positive onset potential of 0.92 V (vs. RHE), half-wave potential of 0.77 V (vs. RHE) and limiting current density of 5.60 mA cm −2 at 0.055 V (vs. RHE). The hydrogen peroxide yield is less than 4.2%, and the electron transfer numbers are between 3.91 and 3.99 at 0.055 V~1.055 V in the catalytic ORR, which indicate that the reaction is dominated by four-electron reduction. The 5Fe95Zn-HPC has higher stability and methyl alcohol resistance in alkaline and acidic solutions. The above results indicate the excellent catalytic ORR performance of the 5Fe95Zn-HPC, almost as the commercial Pt/C. Additionally, 5Fe95Zn-HPC has the capacity to catalyze oxygen evolution reaction (OER) and adsorb methylene blue pollutants. Therefore, this work provides a practical method to design the hierarchical porous carbon-based material with outstanding multi-functions.
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TALANTA
·
2015
·
IF 3.545
Xiaohua Zhou,Xiaole Li,Aijuan Cao,Qiao Lijun,Ajuan Yu,Shusheng Zhang,Yangjie Wu
A new stationary phase for high-performance liquid chromatography was prepared by covalently bonding N-ferrocenyl(benzoyl)amino-acid esters (L 1 ) onto silica gel using 3-aminopropyltriethoxysilane as coupling reagent. The structure of new material was characterized by infrared spectroscopy , elemental analysis and thermogravimetric analysis . The chromatographic behavior of the phase was illustrated in reversed-phase (RP) and normal-phase (NP) modes using polycyclic aromatic hydrocarbons (PAHs), aromatics positional isomers, amines, 5-nitroimidazoles, organophosphorus pesticides and phenols as probes. Multiple mechanisms including hydrophobic, hydrogen bonding , π–π, dipole–dipole, charge-transfer and acid–base equilibrium interactions are involved. Thus, multi-interaction mechanisms and mixed-mode separation of the new phase can very likely guarantee its excellent chromatographic performance for the analysis of complex samples. The L 1 AminoSil column was successfully employed for the analysis of organophosphorus pesticides in vegetable.
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危险品化学品经营许可证（带存储）