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Unraveling the degradation mechanism of LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2) at the high cut-off voltage for lithium ion batteries 被引量:3
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作者 Liming Wang Qingmei Su +10 位作者 Bin Han Weihao Shi Gaohui Du Yunting Wang Huayv Li Lin Gu Wenqi Zhao Shukai Ding Miao Zhang Yongzhen Yang Bingshe Xu 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2023年第2期428-437,I0011,共11页
LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)layered oxides have been regarded as promising alternative cathodes for the next generation of high-energy lithium ion batteries(LIBs)due to high discharge capacities and energy ... LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)layered oxides have been regarded as promising alternative cathodes for the next generation of high-energy lithium ion batteries(LIBs)due to high discharge capacities and energy densities at high operation voltage.However,the capacity fading under high operation voltage still restricts the practical application.Herein,the capacity degradation mechanism of NCM811 at atomic-scale is studied in detail under various cut-off voltages using aberration-corrected scanning transmission electron microscopy(STEM).It is observed that the crystal structure of NCM811 evolution from a layered structure to a rock-salt phase is directly accompanied by serious intergranular cracks under 4.9 V,which is distinguished from the generally accepted structure evolution of layered,disordered layered,defect rock salt and rock salt phases,also observed under 4.3 and 4.7 V.The electron energy loss spectroscopy analysis also confirms the reduction of Ni and Co from the surface to the bulk,not the previously reported only Li/Ni interlayer mixing.The degradation mechanism of NCM811 at a high cut-off voltage of4.9 V is attributed to the formation of intergranular cracks induced by defects,the direct formation of the rock salt phase,and the accompanied reduction of Ni^(2+)and Co^(2+)phases from the surface to the bulk. 展开更多
关键词 Ni-rich layered cathode Electrochemical performance Degradation mechanism Crack Atomic scale
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Stabilized Nickel-Rich-Layered Oxide Electrodes for High-Performance Lithium-Ion Batteries
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作者 Zahra Ahaliabadeh Ville Miikkulainen +7 位作者 Miia Mäntymäki Mattia Colalongo Seyedabolfazl Mousavihashemi Lide Yao Hua Jiang Jouko Lahtinen Timo Kankaanpää Tanja Kallio 《Energy & Environmental Materials》 SCIE EI CAS CSCD 2024年第6期60-73,共14页
This work made use of the Aalto University Otanano-Nanomicroscopy Center and RAMI infrastructures.Financial support from Business Finland NextGenBat[grant number 211849]is greatly acknowledged.The tomography experimen... This work made use of the Aalto University Otanano-Nanomicroscopy Center and RAMI infrastructures.Financial support from Business Finland NextGenBat[grant number 211849]is greatly acknowledged.The tomography experiment was performed at the beamline ID16B of the European Synchrotron Radiation Facility(ESRF),Grenoble,France,in the frame of proposal CH-6644.The patent titled“Stabilized Positive Electrode Material to Enable High Energy and Power Density Lithium-Ion Batteries”(IPD3173)is pertinent to this manuscript.It was filed by Zahra Ahaliabadeh and Tanja Kallio,and the patent rights are held by Aalto University. 展开更多
关键词 degradation mechanisms electrolyte decomposition hybrid coatings lithium-ion battery lithium-ion kinetics molecular layer deposition NMC811
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Carboxylates as green corrosion inhibitors of magnesium alloy for biomedical application
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作者 A.S.Gnedenkov S.L.Sinebryukhov +3 位作者 A.D.Nomerovskii V.S.Marchenko A.Yu.Ustinov S.V.Gnedenkov 《Journal of Magnesium and Alloys》 SCIE EI CAS CSCD 2024年第7期2909-2936,共28页
The efficiency of the green inhibitors(sodium salts of fumarate,glycolate and gluconate)in suppressing corrosion of the structural MA8 magnesium alloy(Mg–Mn–Ce)and the biomedical Mg–0.8Ca alloy was studied using th... The efficiency of the green inhibitors(sodium salts of fumarate,glycolate and gluconate)in suppressing corrosion of the structural MA8 magnesium alloy(Mg–Mn–Ce)and the biomedical Mg–0.8Ca alloy was studied using the hydrogen evolution measurements,mass loss test,EIS,PDP,SVET/SIET.The analysis of the morphology,chemical composition,and growth kinetic of corrosion films formed in 0.9 wt%NaCl solution with and without corrosion inhibitors was carried out.The most compact surface film with the smallest thickness was formed in a saline solution with sodium fumarate.The Mg alloy samples exhibited the highest polarization resistance,the lowest localized electrochemical activity,and the lowest corrosion rate in saline with the addition of sodium fumarate and sodium glycolate.The efficiency of the applied inhibitors was up to 81%.The model of the corrosion mechanism based on the sorption of molecules of organic inhibitors is proposed.The results show the high compatibility of the used inhibitors with the calcium-phosphate PEO-matrix,indicating the possibility of forming a self-healing coating by means of these active substances. 展开更多
关键词 Magnesium and its alloys Organic inhibitor Electrochemical behavior PEO-coatin Bioresorbable implant Degradation mechanism
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Microwave photocatalytic degradation of Rhodamine B using TiO_2 supported on activated carbon:Mechanism implication 被引量:23
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作者 HE Zhong,YANG Shaogui,JU Yongming,SUN Cheng State Key Laboratory of Pollution Control and Resource Reuse,School of the Environment,Nanjing University,Nanjing 210093,China. 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2009年第2期268-272,共5页
The photocatalytic degradation of Rhodamine B (RhB) was carried out using TiO2 supported on activated carbon (TiO2-AC) under microwave irradiation. Composite catalyst TiO2-AC was prepared and characterized using X... The photocatalytic degradation of Rhodamine B (RhB) was carried out using TiO2 supported on activated carbon (TiO2-AC) under microwave irradiation. Composite catalyst TiO2-AC was prepared and characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM) and Brunauer-Emmett-Teller (BET). In the process of microwave-enhanced photocatalysis (MPC), RhB (30 mg/L) was almost completely decoloured in 10 min, and the mineralization efficiency was 96.0% in 20 min. The reaction rate constant of RhB in MPC using TiO2-AC by pseudo first-order reaction kinetics was 4.16 times of that using Degussa P25. Additionally, according to gas chromatography/mass spectrometry (GC/MS) and liquid chromatography/mass spectrometry (LC/MS) identification, the major intermediates of RhB in MPC included two kinds of N-de-ethylation intermediates (N,N-diethyl-N'-ethyl-rhodamine (DER)), oxalic acid, malonic acid, snccinic acid, and phthalic acid, maleic acid, 3-nitrobenzoic acid, and so on. The degradation of RhB in MPC was mainly attributed to the destruction of the conjugated structure, and then the intermediates transformed to acid molecules which were mineralized to water and carbon dioxide. 展开更多
关键词 microwave photocatalytic WiO2 activated carbon Rhodamine B degradation mechanism
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Degradation mechanism of 2,4,6-trinitrotoluene in supercritical water oxidation 被引量:15
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作者 CHANG Shuang-jun LIU Yu-cun 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2007年第12期1430-1435,共6页
The 2,4,6-trinitrotoluene (TNT) is a potential carcinogens and TNT contaminated wastewater, which could not be effectively disposed with conventional treatments. The supercritical water oxidation (SCWO) to treat T... The 2,4,6-trinitrotoluene (TNT) is a potential carcinogens and TNT contaminated wastewater, which could not be effectively disposed with conventional treatments. The supercritical water oxidation (SCWO) to treat TNT contaminated wastewater was studied in this article, The TNT concentration in wastewater was measured by high-performance liquid chromatograph (HPLC) and the degraded intermediates were analyzed using GC-MS. The results showed that SCWO could degrade TNT efficiently in the presence of oxygen. The reaction temperature, pressure, residence time and oxygen excess were the main contributing factors in the process. The decomposition of TNT was accelerated as the temperature or residence time increased. At 550℃, 24 MPa, 120 s and oxygen excess 300%, TNT removal rate could exceed 99.9%. Partial oxidation occured in SCWO without oxygen. It was concluded that supercritical water was a good solvent and had excellent oxidation capability in the existence of oxygen. The main intermediates of TNT during SCWO included toluene, 1,3,5-trinitrobenzene, nitrophenol, naphthalene, fluorenone, dibutyl phthalate, alkanes and several dimers based on the intermediate analysis. Some side reactions, such as coupled reaction, hydrolysis reaction and isomerization reaction may take place simultaneously when TNT was oxidized by SCWO. 展开更多
关键词 supercritical water oxidation TNT degradation mechanism wastewater treatment
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Mechanism of progressive failure of a slope with a steep joint under the action of freezing and thawing:model test 被引量:3
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作者 LI Cong ZHANG Rong-tang +6 位作者 ZHU Jie-bing LU Bo SHEN Xiao-ke WANG Xiao-wei LIU Jie-sheng WU Liang-liang ZHANG Xin-zhou 《Journal of Mountain Science》 SCIE CSCD 2022年第10期2999-3012,共14页
The stability of slope rock masses is influenced by freeze-thaw cycles in cold region,and the mechanism of stability deterioration is not clear.In order to understand the damage and progressive failure characteristics... The stability of slope rock masses is influenced by freeze-thaw cycles in cold region,and the mechanism of stability deterioration is not clear.In order to understand the damage and progressive failure characteristics of rock masses under the action of freezing and thawing,a model test was conducted on slope with steep joint in this study.The temperature,frost heaving pressure and deformation of slope rock mass were monitored in real-time during the test and the progressive failure mode was studied.The experimental results show that the temperature variations of cracking and the rock mass of a slope are different.There are obvious latent heat stages in the temperature-change plot in the crack,but not in the slope rock masses.The frost heaving effect in the fracture is closely related to the constraint conditions,which change with the deformation of the fracture.The frost heaving pressure fluctuates periodically during freezing and continues to decrease during thawing.The surface deformation of the rock mass increases during freezing,and the deformation is restored when it thaws.Freeze-thaw cycling results in residual deformation of the rock mass which cannot be fully restored.Analysis shows that the rock mass at the free side of the steep-dip joint rotates slightly under the frost heaving effect,causing fracture propagation.The fracture propagation pattern is a circular arc at the beginning,then extends to the possible sliding direction of the rock mass.Frost heaving force and fracture water pressure are the key factors for the failure of the slope,which can cause the crack to penetrate the rock mass,and a landslide ensues when the overall anti-sliding resistance of the rock mass is overcome. 展开更多
关键词 Rock slope Fractured rock mass Freeze-thaw cycle Model experiment Stability degradation mechanism Failure mode
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The Mechanism of Carotenoid Degradation in Flue-Cured Tobacco and Changes in the Related Enzyme Activities at the Leaf-Drying Stage During the Bulk Curing Process 被引量:6
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作者 SONG Zhao-peng LI Tong-shuai +3 位作者 ZHANG Yong-gang CAO Hui-jing GONG Chang-rong ZHANG Wei-jian 《Agricultural Sciences in China》 CSCD 2010年第9期1381-1388,共8页
The mechanism of carotenoid degradation and the changes in the activities of related enzymes in flue-cured tobacco at the leaf-drying stage during the bulk-curing process were studied in order to provide theoretical b... The mechanism of carotenoid degradation and the changes in the activities of related enzymes in flue-cured tobacco at the leaf-drying stage during the bulk-curing process were studied in order to provide theoretical basis for optimization of curing technology. The effect of different rising speeds of temperature on the carotenoid degradation and the related enzymes activities at the color-fixing stage during the bulk curing process was studied by using the electric-heated fluecuring barn designed by Henan Agricultural University, China, based on curing technology with yellowing at low temperature and moderate humidity and leaf drying at moderate humidity. The results showed that the carotenoid degradation components (β-carotene, lutein, neoxanthin, and violaxthin) decreased gradually at the color-fixing stage during the bulk curing process. The carotenoid degradation components viz.,β-carotene, lutein, neoxanthin, and violaxthin at the slow heating curing (T1) were relatively higher than the rapid heating curing (T2) accounting for 10, 2, 32 and 32% respectively, but there were no differences among treatments (P〉 0.05). The effect of different conditions of curing on the activities of enzymes related to carotenoids degradation were significant. The lipoxygenase, phenylalanine ammonialyase, peroxidase, and polyphenol oxidase enzymes had a bidirectional effect on the quality of tobacco leaves and it was beneficial to form more premise matter of aroma based on the higher enzyme activities at the early leaf-drying stage. The slow heating could regulate the change in various enzymes' activities reasonably, making cell redox reaction to reach the dynamic balance and make the degradation of carotenoids adequately. Meanwhile, it could avoid the occurrence of browning reaction and provide foundation for improving the quality of tobacco and optimization of technology for bulk curing and further enhancing aroma. 展开更多
关键词 bulk curing leaf-drying stage carotenoids mechanism of degradation enzyme
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The degradation mechanism of an AlGaN/GaN high electron mobility transistor under step-stress 被引量:1
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作者 陈伟伟 马晓华 +3 位作者 侯斌 祝杰杰 张进成 郝跃 《Chinese Physics B》 SCIE EI CAS CSCD 2013年第10期508-511,共4页
Step-stress experiments are performed in this paper to investigate the degradation mechanism of an AIGaN/GaN high electron mobility transistor (HEMT). It is found that the stress current shows a recoverable decrease... Step-stress experiments are performed in this paper to investigate the degradation mechanism of an AIGaN/GaN high electron mobility transistor (HEMT). It is found that the stress current shows a recoverable decrease during each voltage step and there is a critical voltage beyond which the stress current starts to increase sharply in our experiments. We postulate that defects may be randomly induced within the A1GaN barrier by the high electric field during each voltage step. But once the critical voltage is reached, the trap concentration will increase sharply due to the inverse piezoelectric effect. A leakage path may be introduced by excessive defect, and this may result in the permanent degradation of the A1GaN/GaN HEMT. 展开更多
关键词 A1GaN/GaN HEMT RELIABILITY degradation mechanism inverse piezoelectric effect
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STUDY OF DEGRADATION MECHANISM AND PACKAGING OF ORGANIC LIGHT EMITTING DEVICES
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作者 Gu Xu Materials Science and Engineering McMaster University Hamilton, Ontario, L8S 4L7 Canada 《Chinese Journal of Polymer Science》 SCIE CAS CSCD 2003年第5期527-531,共5页
Organic Light Emitting Devices (OLED) have attracted much attention recently, for their applications in futureFlat Panel Displays and lighting products. However, their fast degradation remained a major obstacle to the... Organic Light Emitting Devices (OLED) have attracted much attention recently, for their applications in futureFlat Panel Displays and lighting products. However, their fast degradation remained a major obstacle to theircommercialization. Here we present a brief summary of our studies on both extrinsic and intrinsic causes for the fastdegradation of OLEDs. In particular, we focus on the origin of the dark spots by 'rebuilding' cathodes, which confirms thatthe growth of dark spots occurs primarily due to cathode delamination. In the meantime, we recapture the findings from thesearch for suitable OLED packaging materials, in particular polymer composites, which provide both heat dissipation andmoisture resistance, in addition to electrical insulation. 展开更多
关键词 Organic light emitting devices Degradation mechanism Dark spots Cathode rebuilding Polymer composites Heat dissipation and moisture resistance
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Mechanisms of Accelerated Degradation in the Front Cells of PEMFC Stacks and Some Mitigation Strategies
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作者 LI Pengcheng PEI Pucheng +3 位作者 HE Yongling YUAN Xing CHAO Pengxiang WANG Xizhong 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2013年第6期1250-1258,共9页
The accelerated degradation in the front ceils of a polymer electrolyte membrane fuel cell(PEMFC) stack seriously reduces the reliability and durability of the whole stack. Most researches only focus on the size and... The accelerated degradation in the front ceils of a polymer electrolyte membrane fuel cell(PEMFC) stack seriously reduces the reliability and durability of the whole stack. Most researches only focus on the size and configuration of the gas intake manifold, which may lead to the maldistribution of flow and pressure. In order to find out the mechanisms of the accelerated degradation in the front cells, an extensive program of experimental and simulation work is initiated and the results are reported. It is found that after long-term lifetime tests the accelerated degradation in the front cells occurs in all three fuel cell stacks with different flow-fields under the U-type feed configuration. Compared with the rear cells of the stack, the voltage of the front cells is much lower at the same current densities and the membrane electrode assembly(MEA) has smaller active area, more catalyst particle agglomeration and higher ohmic impedance. For further investigation, a series of three dimensional isothermal numerical models are built to investigate the degradation mechanisms based on the experimental data. The simulation results reveal that the dry working condition of the membrane and the effect of high-speed gas scouting the MEA are the main causes of the accelerated degradation in the front cells of a PEM fuel cell stack under the U-type feed configuration. Several mitigation strategies that would mitigate these phenomena are presented: removing cells that have failed and replacing them with those of the same aging condition as the average of the stack; choosing a Z-type feed pattern instead of a U-type one; putting several air flow-field plates without MEA in the front of the stack; or exchanging the gas inlet and outlet alternately at a certain interval. This paper specifies the causes of the accelerated degradation in the front cells and provides the mitigation strategies. 展开更多
关键词 Proton exchange membrane fuel cell Degradation mechanism Mitigation strategy
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STUDIES ON FLUORESCENCE ENHANCING EFFECT AND ALKALINE DEGRADATION MECHANISM OF DOXYCYCLINE AND METHACYCLINE
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作者 Yi Bing ZHAO Department of Chemistry,Xiamen University,Xiamen 361005Wen Bao CHANG Yun Xiang CI Department of Chemistry,Peking University,Beijing 100871 《Chinese Chemical Letters》 SCIE CAS CSCD 1993年第9期791-792,共2页
Degradation reaction of doxycycline or methacycline was carried out in KOH solution and intense fluorescence was obtained.A degradation mechanism of doxycycline or methacycline was suggested.
关键词 HC DC STUDIES ON FLUORESCENCE ENHANCING EFFECT AND ALKALINE DEGRADATION mechanism OF DOXYCYCLINE AND METHACYCLINE KOH
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Degradation mechanism of two-dimensional electron gas density in high Al-content AlGaN/GaN heterostructures
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作者 张进成 郑鹏天 +2 位作者 张娟 许志豪 郝跃 《Chinese Physics B》 SCIE EI CAS CSCD 2009年第7期2998-3001,共4页
This paper finds that the two-dimensional electron gas density in high Al-content A1GaN/GaN heterostructures exhibits an obvious time-dependent degradation after the epitaxial growth. The degradation mechanism was inv... This paper finds that the two-dimensional electron gas density in high Al-content A1GaN/GaN heterostructures exhibits an obvious time-dependent degradation after the epitaxial growth. The degradation mechanism was investigated in depth using Hall effect measurements,high resolution x-ray diffraction,scanning electron microscopy,x-ray photoelectron spectroscopy and energy dispersive x-ray spectroscopy.The results reveal that the formation of surface oxide is the main reason for the degradation,and the surface oxidation always occurs within the surface hexagonal defects for high Al-content AlGaN/GaN heterostructures. 展开更多
关键词 degradation mechanism two-dimensional electron gas AlGaN/GaN heterostructures surface oxidation
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Degradation Mechanism of the Superconducting Transition Temperature in Nb Thin Films
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作者 宋小会 金贻荣 +2 位作者 樊振军 米振宇 张殿琳 《Chinese Physics Letters》 SCIE CAS CSCD 2015年第4期122-125,共4页
Systemic measurements show that there is no 3D to 2D crossover in the reduction of the superconducting transition temperature Tc in Nb thin films. This result is consistent with all previous measurements while it is c... Systemic measurements show that there is no 3D to 2D crossover in the reduction of the superconducting transition temperature Tc in Nb thin films. This result is consistent with all previous measurements while it is contrary to the prevailing understanding based on the interplay between proximity, localization, and lifetime broadening. Our study indicates that the decrease of Tc can be interpreted by the combined effects of electron-phonon coupling parameter λ and the defect scattering rate pw, being uniquely determined by their ratio λ/ρw. Other factors such as film thickness and irradiation do not produce additional effects beyond these two parameters. 展开更多
关键词 Degradation mechanism of the Superconducting Transition Temperature in Nb Thin Films
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Degradation of Alkaline Lignin in the Lactic Acid-Choline Chloride System under Mild Conditions 被引量:1
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作者 Penghui Li Zhengwei Jiang +3 位作者 Chi Yang Jianpeng Ren Bo Jiang Wenjuan Wu 《Journal of Renewable Materials》 SCIE EI 2023年第5期2233-2248,共16页
Lignin is a natural polymer,second only to cellulose in natural reserves.Degradation is one of the ways to achieve the high-value transformation of lignin.Deep eutectic solvent(DES)thermal degradation of lignin can be... Lignin is a natural polymer,second only to cellulose in natural reserves.Degradation is one of the ways to achieve the high-value transformation of lignin.Deep eutectic solvent(DES)thermal degradation of lignin can be used as an excellent green degradation method.This paper introduces the degradation mechanism and effect of the lactic acid-choline chloride DES system in dissolving and degrading alkaline lignin,and the final solvent recovery.It can also be found from the scanning electron microscope(SEM)images that the surface of the degraded solid product is transformed from smooth to disordered.Fourier transform infrared(FTIR)spectroscopy and 1H-NMR spectroscopy were used to characterize the changes in lignin functional groups during DES treatment.The results showed that the content of phenolic hydroxyl groups increased after degradation,indicating that theβ-O-4 ether bond was broken.The molecular weight of the degraded lignin was observed by gel permeation chromatography(GPC),and the lignin residue with low molecular weight and narrow polydispersity index was obtained.The lowest average molecular weight(Mw)reached 2512 g/mol.The ratio of oxygen to carbon atoms in lignin increased substantially during degradation as measured by X-ray photoelectron spectroscopy(XPS),probably because DES treatment was accompanied by many oxidation reactions,which led to significant structural changes in lignin and a large number of ether bond breakage reactions during the reaction.The main final degradation products are aromatic monomers,vanillin,butyrovanillone,etc. 展开更多
关键词 LIGNIN mild conditions deep eutectic solvents(DES) degradation mechanism
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Interpretable hybrid machine learning demystifies the degradation of practical lithium-sulfur batteries
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作者 Zhi Wei Seh 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2023年第4期54-55,共2页
The ever-increasing future demands of electrification and grid storage have spurred continued research to develop rechargeable battery chemistries for reliable energy storage[1].Beyond current lithium-ion batteries,li... The ever-increasing future demands of electrification and grid storage have spurred continued research to develop rechargeable battery chemistries for reliable energy storage[1].Beyond current lithium-ion batteries,lithium–sulfur battery represents a promising system due to its high energy density(2600 Wh kg^(-1))and low material cost[2]. 展开更多
关键词 Machine learning Lithium-sulfur batteries Battery prognosis Capacity degradation mechanism
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Electrochemical oxidation of perfluoroalkyl and polyfluoroalkyl substances:Mechanisms,implications,and challenges
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作者 ZHOU XuDong ZHONG YaShi +1 位作者 TIAN XiaoChun ZHAO Feng 《Science China(Technological Sciences)》 SCIE EI CAS CSCD 2024年第10期2972-2990,共19页
Perfluoroalkyl and polyfluoroalkyl substances(PFASs)have recently gained considerable attention due to their potential risks to human health and ecosystems.The response to these concerns has led to regulations and ban... Perfluoroalkyl and polyfluoroalkyl substances(PFASs)have recently gained considerable attention due to their potential risks to human health and ecosystems.The response to these concerns has led to regulations and bans on legacy PFASs,such as perfluorooctanoic acid and perfluorooctane sulfonic acid.Thus,fluoride production has shifted toward short-chain PFASs and emerging fluorinated alternatives.Several technologies are available for PFAS degradation,among which electrochemical oxidation(EO)is a promising method to mineralize legacy PFASs and other emerging fluorinated alternatives in water treatment.This review provides an overview of the recent advancements in EO,comprehensively elucidating PFAS degradation mechanisms at the anode and exploring key factors that influence PFAS removal efficiency,such as anode materials as well as reactor designs and configurations.Moreover,the review elucidates the impact of operating conditions and parameters,including current density,electrolytes,pH,initial PFAS concentrations,and other coexisting pollutants,on the EO process.Finally,the constraints in the EO process are discussed when considering practical implementations,including undesired by-product generation,incomplete mineralization resulting in the accumulation of short-chain PFASs,and low PFAS concentrations in the natural environment leading to mass transfer limitations and low defluorination efficiency.Consequently,this review provides a perspective on potential solutions integrating the pre-concentration steps and EO process for effective PFAS remediation. 展开更多
关键词 electrochemical oxidation legacy PFASs fluorinated alternatives degradation mechanisms influencing factors
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Novel insights into the dehalogenation mechanism and ecotoxicity assessment of 6:2 Cl-PFESA from density functional theory calculations
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作者 Youxin Xu Chenxi Zhang +4 位作者 Zhe Wang Bing Chen Xiaomin Sun Shuguang Wang Huifang Tian 《Emerging Contaminants》 CSCD 2024年第2期115-122,共8页
The electroplating industry is the main source of 6:2 chlorinated polyfluorinated ether sulfonate(6:2 Cl-PFESA)pollution,which presents risks to human health and the environment.It is therefore crucial to develop effe... The electroplating industry is the main source of 6:2 chlorinated polyfluorinated ether sulfonate(6:2 Cl-PFESA)pollution,which presents risks to human health and the environment.It is therefore crucial to develop effective 6:2 Cl-PFESA degradation techniques.Persulfate oxidation is a potential treatment method for 6:2 Cl-PFESA due to its outstanding oxidative degradability following the generation of the sulfate radical(SO_(4)^(•−))and hydroxyl radical(•OH).It has proven difficult to acquire a full understanding of the reaction mechanism and formation of intermediate(IM)products through conventional experimental studies because they are costly and time-consuming.Therefore,a theoretical analysis method based on density functional theory(DFT)calculations was applied.The DFT results showed that electron transfer for the degradation of 6:2 Cl-PFESA could be initiated by the protonated sulfate radical(HSO_(4)•,ΔG≠SET=9.16 kcal/mol),rather than SO4•−(ΔG≠SET=41.60 kcal/mol).After desulfonation,the reaction underwent stepwise decarboxylation cycles under the action of•OH,leading to the elimination of the CF_(2) units until there was complete mineralization into HCl,HF,and CO_(2).Furthermore,the IMs and the end products of 6:2 Cl-PFESA were evaluated using ECOSAR and TEST software.The low bioaccumulation of the short-chain IMs meant that they could be considered safe in terms of ecotoxicity and health effects.This research determined the theoretical and mechanistic basis of the effects of persulfate in the treatment of water containing 6:2 Cl-PFESA,and its structural analogues. 展开更多
关键词 Active free radicals Dehalogenation reaction Degradation mechanisms Theoretical prediction Ecotoxicity assessment
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Corrosion resistances of metallic materials in environments containing chloride ions:A review 被引量:10
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作者 Xian-man ZHANG Zai-yu CHEN +3 位作者 Hong-feng LUO Teng ZHOU Yu-liang ZHAO Zi-cheng LING 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2022年第2期377-410,共34页
Corrosion,more specifically,pitting corrosion happening extremely in marine environments,leads to lifespan of materials drastically decreasing in service,which causes enormous economic loss and even environmental disa... Corrosion,more specifically,pitting corrosion happening extremely in marine environments,leads to lifespan of materials drastically decreasing in service,which causes enormous economic loss and even environmental disaster and casualties.In the past decade,increasing efforts have been made to study the corrosion behaviors of materials in chloride-containing aqueous environments.Herein,this work provides an overview of recent progress in understanding the degradation mechanism and improving the corrosion resistance and corrosion-wear resistance of materials from bulk metal to surface treatment involving organic coating,metal and its alloy or compound coating.The particular emphasis is given to the periodic layered structures(PLSs),whose anti-corrosion properties outperformed others to some extent,wherever in terms of bulk metal or surface treatment,regardless of aggressive environment(corrosion or corrosion-wear conditions).Numerical simulation based on kinds of models at different scales is introduced to deeply understand the process of corrosion and/or corrosion-wear in chloride-containing aqueous environment.Combined experimental result with numerical simulation,the micro-galvanic corrosion dominated degradation mechanism of PLSs is critically analyzed.Types of setups to realize corrosion-wear in laboratory are also summarized.At last,future research and development are prospected,offering to develop a basic application of PLSs designed by corrosion protection methodology in the near future. 展开更多
关键词 pitting corrosion chloride ion periodic layered structure galvanic corrosion degradation mechanism
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Electrochemical oxidation of rhodamine B by PbO_2/Sb-SnO_2/TiO_2 nanotube arrays electrode 被引量:11
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作者 Jia Wu Kai Zhu +1 位作者 Hao Xu Wei Yan 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2019年第6期917-927,共11页
A PbO2/Sb-SnO2/TiO2 nanotube array composite electrode was successfully synthesized and its electrochemical oxidation properties were investigated.Field-emission scanning electron microscopy(FE-SEM)and X-ray diffracti... A PbO2/Sb-SnO2/TiO2 nanotube array composite electrode was successfully synthesized and its electrochemical oxidation properties were investigated.Field-emission scanning electron microscopy(FE-SEM)and X-ray diffraction(XRD)results showed that the PbO2 coating was composed of anα-PbO2 inner layer and aβ-PbO2 outer layer.Accelerated life measurement indicated that the composite electrode had a lifetime of 815 h.Rhodamine B(RhB)was employed as a model pollutant to analyze the electrocatalytic activity of the electrode.The effects of initial RhB concentration,current density,initial pH,temperature,and chloride ion concentration on the electrochemical oxidation were investigated in detail.Inductively coupled plasma atomic emission spectroscopy(ICP-AES)results suggested that the concentration of leached Pb^2+in the electrolyte during the electrocatalytic oxidation process can be neglected.Finally,the degradation mechanism during the electrocatalytic oxidation process was proposed based on the results of solid-phase micro-extraction-gas chromatography-mass spectrometry(SPME-GC-MS).The high electrocatalytic performance of the composite electrode makes it a promising anode for the treatment of organic pollutants in aqueous solution. 展开更多
关键词 TiO2 nanotube array Electrochemical oxidation Rhodamine B Degradation mechanism
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Synthesis of novel p-n heterojunction m-Bi_2O_4/BiOCl nanocomposite with excellent photocatalytic activity through ion-etching method 被引量:8
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作者 Junxiu Wang Zhenzong Zhang +4 位作者 Xi Wang Yi Shen Yongfu Guo Po Keung Wong Renbi Bai 《Chinese Journal of Catalysis》 SCIE EI CAS CSCD 北大核心 2018年第11期1792-1803,共12页
A novel p‐n heterostructure photocatalyst m‐Bi2O4/BiOCl was successfully synthetized through a facile ion‐etching method.Via adjusting the added volume of HCl solution,a series of different ratios of composite phot... A novel p‐n heterostructure photocatalyst m‐Bi2O4/BiOCl was successfully synthetized through a facile ion‐etching method.Via adjusting the added volume of HCl solution,a series of different ratios of composite photocatalysts were obtained.The as‐prepared samples of physical,chemical and optical characteristics were examined by X‐ray diffraction,scanning electron microscope,transmission electron microscope,energy dispersive X‐ray spectroscopy,selected‐area electron diffraction,Fourier transform infrared absorption,Raman microscope,N2 adsorption‐desorption,X‐ray photoelectron spectroscopy and UV‐vis spectrum technologies.The photocatalysts showed high degradation rate and complete mineralization ability for methyl orange and tetracycline solution under visible light.The reaction rate constant of m‐Bi2O4/BiOCl for methyl orange was 52.28 times higher than that of BiOCl.The characterization presented a good stability of materials.Furthermore,the photocurrent response test certified that the heterostructure effectively accelerated the separation and migration of photo‐generated carries.The scavenger experiments evidenced that hole(h+)and superoxide radical(?O2?)were the primary active radicals.A possible photocatalytic mechanism was proposed.This work provided an alternative photocatalyst applied to water environmental remediation. 展开更多
关键词 Dibismuth tetroxide Photocatalysis Methylene orange TETRACYCLINE Degradation mechanism
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