Carbon-doped copper ferrite(C–CuFe_(2)O_(4))was synthesized by a simple two-step hydrothermal method,which showed enhanced tetracycline hydrochloride(TCH)removal efficiency as compared to the pure CuFe_(2)O_(4) in Fe...Carbon-doped copper ferrite(C–CuFe_(2)O_(4))was synthesized by a simple two-step hydrothermal method,which showed enhanced tetracycline hydrochloride(TCH)removal efficiency as compared to the pure CuFe_(2)O_(4) in Fenton-like reaction.A removal efficiency of 94%was achieved with 0.2 g L^(-1) catalyst and 20 mmol L^(-1) H_(2)O_(2) within 90 min.We demonstrated that 5%C–CuFe_(2)O_(4) catalyst in the presence of H_(2)O_(2) was significantly efficient for TCH degradation under the near-neutral pH(5–9)without buffer.Multiple techniques,including SEM,TEM,XRD,FTIR,Raman,XPS M€ossbauer and so on,were conducted to investigate the structures,morphologies and electronic properties of as-prepared samples.The introduction of carbon can effectively accelerate electron transfer by cooperating with Cu and Fe to activate H_(2)O_(2) to generate·OH and·O_(2)^(-).Particularly,theoretical calculations display that the p,p,d orbital hybridization of C,O,Cu and Fe can form C–O–Cu and C–O–Fe bonds,and the electrons on carbon can transfer to metal Cu and Fe along the C–O–Fe and C–O–Cu channels,thus forming electron-rich reactive centers around Fe and Cu.This work provides lightful reference for the modification of spinel ferrites in Fenton-like application.展开更多
For present solid oxide fuel cells(SOFCs),rapid performance degradation is observed in the initial aging process,and the dis-cussion of the degradation mechanism necessitates quantitative analysis.Herein,focused ion b...For present solid oxide fuel cells(SOFCs),rapid performance degradation is observed in the initial aging process,and the dis-cussion of the degradation mechanism necessitates quantitative analysis.Herein,focused ion beam-scanning electron microscopy was em-ployed to characterize and reconstruct the ceramic microstructures of SOFC anodes.The lattice Boltzmann method(LBM)simulation of multiphysical and electrochemical processes in the reconstructed models was performed.Two samples collected from industrial-size cells were characterized,including a reduced reference cell and a cell with an initial aging process.Statistical parameters of the reconstructed microstructures revealed a significant decrease in the active triple-phase boundary and Ni connectivity in the aged cell compared with the reference cell.The LBM simulation revealed that activity degradation is dominant compared with microstructural degradation during the initial aging process,and the electrochemical reactions spread to the support layer in the aged cell.The microstructural and activity de-gradations are attributed to Ni migration and coarsening.展开更多
Adsorption coupled with photocatalytic degradation is proposed to fulfill the removal and thorough elimination of organic dyes.Herein,we report a facile hydrothermal synthesis of MIL-100(Fe)/GO photocatalysts.The adso...Adsorption coupled with photocatalytic degradation is proposed to fulfill the removal and thorough elimination of organic dyes.Herein,we report a facile hydrothermal synthesis of MIL-100(Fe)/GO photocatalysts.The adsorption and photocatalytic degradation process of methylene blue(MB)on MIL‐100(Fe)/GO composites were systematically studied from performance and kinetic perspectives.A possible adsorption‐photocatalytic degradation mechanism is proposed.The optimized 1M8G composite achieves 95%MB removal(60.8 mg/g)in 210 min and displays well recyclability over ten cycles.The obtained MB adsorption and degradation results are well fitted onto Langmuir isotherm and pseudo‐second order kinetic model.This study shed light on the design of MOFs based composites for water treatment.展开更多
A novel iron-glutamate-silicotungstate ternary complex(FeШGluS iW) was synthesized from ferric chloride(FeI II),glutamic acid(Glu),and silicotungstic acid(SiW),and used as a heterogeneous Fenton-like catalyst...A novel iron-glutamate-silicotungstate ternary complex(FeШGluS iW) was synthesized from ferric chloride(FeI II),glutamic acid(Glu),and silicotungstic acid(SiW),and used as a heterogeneous Fenton-like catalyst for 4-chlorophenol(4-CP) degradation at neutral pH value. The prepared FeШGluS iW was characterized using inductively coupled plasma atomic emission spectroscopy,thermogravimetry,Fourier-transform infrared spectroscopy,ultraviolet-visible diffuse reflectance spectroscopy,X-ray diffraction,and field-emission scanning electron microscopy. The results showed that FeШGluS iW has the formula [Fe(C5H8NO4)(H2O)]2SiW 12O40?13H2O,with glutamate moiety and Keggin-structured SiW 12O404- heteropolyanion. The catalyst showed high catalytic activity in 4-CP degradation in the dark and under irradiation. Under the conditions of 4-CP 100 mg/L,FeШGluS iW 1.0 g/L,H2O2 20 mmol/L,and pH = 6.5,4-CP was completely decomposed in 40 min in the dark and in 15 min under irradiation. When the reaction time was prolonged to 2 h,the corresponding total organic carbon removals under dark and irradiated conditions were ca. 27% and 72%,respectively. The high catalytic activity of FeI IIGluS iW is resulted from hydrogen bonding of H2O2 on the FeI IIGluS iW surface. The enhanced degradation of 4-CP under irradiation arises from simultaneous oxidation of 4-CP through Fenton-like and photocatalytic processes respectively catalyzed by ferric iron and the SiW 12O404- hetropolyanion in FeШGluS iW.展开更多
Lithium-rich layered oxides(LLOs)are promising candidate cathode materials for safe and inexpensive high-energy-density Li-ion batteries.However,oxygen dimers are formed from the cathode material through oxygen redox ...Lithium-rich layered oxides(LLOs)are promising candidate cathode materials for safe and inexpensive high-energy-density Li-ion batteries.However,oxygen dimers are formed from the cathode material through oxygen redox activity,which can result in morphological changes and structural transitions that cause performance deterioration and safety concerns.Herein,a flake-like LLO is prepared and aberration-corrected scanning transmission electron microscopy(STEM),in situ high-temperature X-ray diffraction(HT-XRD),and soft X-ray absorption spectrum(sXAS)are used to explore its crystal facet degradation behavior in terms of both thermal and electrochemical processes.Void-induced degradation behavior of LLO in different facet reveals significant anisotropy at high voltage.Particle degradation originates from side facets,such as the(010)facet,while the close(003)facet is stable.These results are further understood through ab initio molecular dynamics calculations,which show that oxygen atoms are lost from the{010}facets.Therefore,the facet degradation process is that oxygen molecular formed in the interlayer and accumulated in the ab plane during heating,which result in crevice-voids in the ab plane facets.The study reveals important aspects of the mechanism responsible for oxygen-anionic activity-based degradation of LLO cathode materials used in lithium-ion batteries.In particular,this study provides insight that enables precise and efficient measures to be taken to improve the thermal and electrochemical stability of an LLO.展开更多
In this paper, we present a proof-of-concept study of the enhancement of photocatalytic activity via a combined strategy of fabricating a visible-light responsive ternary heterostructure and improving overall photosta...In this paper, we present a proof-of-concept study of the enhancement of photocatalytic activity via a combined strategy of fabricating a visible-light responsive ternary heterostructure and improving overall photostability by incorporating magnetic zinc oxide/graphene/iron oxide (ZGF). A solvothermal approach was used to synthesize the catalyst. X-ray diffraction (XRD), scanning electron microscopic, energy dispersive X-ray, transmission electron microscopic, vibrating sample magnetometric, and ultraviolet–visible diffuse reflectance spectroscopic techniques were used to characterize the synthesized samples. The obtained optimal Zn(NO_(3))_(2) concentration, temperature, and heating duration were 0.10 mol/L, 600℃, and 1 h, respectively. The XRD pattern revealed the presence of peaks corresponding to zinc oxide, graphene, and iron oxide, indicating that the ZGF catalyst was effectively synthesized. Furthermore, when the developed ZGF was used for methylene blue dye degradation, the optimum irradiation time, dye concentration, catalyst dosage, irradiation intensity, and solution pH were 90 min, 10 mg/L, 0.03 g/L, 100 W, and 8.0, respectively. Therefore, the synthesized ZGF system could be used as a catalyst to degrade dyes in wastewater samples. This hybrid nanocomposite consisting of zinc oxide, graphene, and iron oxide could also be used as an effective photocatalytic degrader for various dye pollutants.展开更多
The effects of oxidant dosage,oxidation temperature and time on the degradation of soda lignin by hydrogen peroxide with and without the presence of microwave irradiation were investigated.It is found that the oxidati...The effects of oxidant dosage,oxidation temperature and time on the degradation of soda lignin by hydrogen peroxide with and without the presence of microwave irradiation were investigated.It is found that the oxidative degradation of lignin includes the cleavage of ether bond inβ-O-4 structure,the partial destruction of aromatic ring,and the re-condensation of the degraded lignin.Compared to the conventionally heated oxidation of lignin,the microwave irradiation efficiently facilitates the degradation of the lignin with high molecular weight and the re-condensation of that with low molecular weight at a low oxidant dosage,low oxidation temperature,or a short oxidation time,which leads to the formation of the degraded lignin with narrower molecular weight distribution and lower molecular weight.Additionally,the lignin degraded in the presence of microwave irradiation has the characteristics of higher content of phenolic hydroxyl group,lower content of methoxyl group,and lower degree of condensation,which enhances the reactivity of lignin.Therefore,the oxidative degradation of lignin assisted by microwave irradiation may be a new pretreatment approach for efficiently utilizing the soda lignin.展开更多
The study focused on the application of high-resolution mass spectrometry for the identification of impurities in pharmaceutical small molecules. A high-performance liquid chromatography (HPLC) coupled high resolution...The study focused on the application of high-resolution mass spectrometry for the identification of impurities in pharmaceutical small molecules. A high-performance liquid chromatography (HPLC) coupled high resolution mass spectrometer (HRMS) was used for identification of oxidative degradation impurities (DIs) of lansoprazole. The utilization of HRMS facilitates to determine the accurate mass of impurities and their fragment/product ions. A fast mass spectrometer (MS) compatible reverse phase chromatography method was used to investigate the oxidative stressed impurities. HPLC column;C18 (50 × 4.6 mm, 3.5 μm) was used with gradient elution. Spectral data acquired using information dependent acquisition (IDA) with real time dynamic background subtraction algorithm (DBS). Three oxidative impurities: DI-I (m/z 386.0781), DI-II (m/z 402.0734) and DI-III (m/z 386.0785), was observed during this study;interpretation of high resolution spectral data of all three impurities was carried out;elemental composition and molecular structure was proposed for major fragments. In this study mass error was found ≤7.7 parts per million (ppm).展开更多
A fully characterised natural rubber latex was subjected to mechanical degradation by stirring at intervals. The resistance to oxidative degradation of the different samples were studied by measuring the Plasticity r...A fully characterised natural rubber latex was subjected to mechanical degradation by stirring at intervals. The resistance to oxidative degradation of the different samples were studied by measuring the Plasticity retention indices (PRI). The results show that there is an enhancement of the PRI from 57% for the undegraded rubber to 79% for the one-hour degraded sample. Further degradation resulted in decrease of PRI as time of degradation increased. Therefore, the one-hour degraded sample is a special rubber with high oxidation resistance which is of great importance in engineering. (Author abstract) 9 Refs.展开更多
Iron-doped titania nanoparticles exhibit a higher photocatalytic activity than pure TiO_2 for the degradation of nitrite. The optimum Fe-doped content in terms of activity is approximately 0.5%. The increase in photoa...Iron-doped titania nanoparticles exhibit a higher photocatalytic activity than pure TiO_2 for the degradation of nitrite. The optimum Fe-doped content in terms of activity is approximately 0.5%. The increase in photoactivity is probably due to the higher adsorption and the inhibition of electron-hole recombination. The photocatalytic oxidation reaction of nitrite over the Fe-doped TiO_2 catalyst follows zero-order kinetics, which is different from that over pure TiO_2. The reaction rate decreases linearly with the increase of the pH of the solution.展开更多
The natural attapulgite(NAPT)was disaggregated by high-pressure homogenization technology combined with extrusion process to prepare the attapulgite with disaggregated rod crystal bundles(DAPT)and large specific surfa...The natural attapulgite(NAPT)was disaggregated by high-pressure homogenization technology combined with extrusion process to prepare the attapulgite with disaggregated rod crystal bundles(DAPT)and large specific surface area of 133.7 m^(2)/g.NAPT and DAPT were incorporated into the silicone rubber to obtain the composite NAPTSR and DAPT-SR by mechanical blending method,respectively.After thermal oxidative ageing at 300℃ for 0.5 h,temperature for the 5%weight loss increased greatly from 385℃ of the neat silicone rubber to 396-399℃ with addition of NAPT and DAPT.NAPT and DAPT enhanced the interaction between the filler nanoparticles and rubber matrix thus inhibited the nanoparticle agglomeration.The conservation rate of the side methyl group in NAPT-SR and DAPT-SR was greatly improved after ageing.Therefore,the thermal oxidative degradation and ageing performance of the silicone rubber composites was significantly reinforced.Moreover,DAPT could greatly restrain the growth of nanoparticles after ageing.Therefore,DAPT-SR showed the better retention of tensile strength(40.6%),elongation at break(34.9%)and tear strength(30.1%)compared with the corresponding mechanical properties of the neat silicone rubber(10.6%,7.4%,and 5.0%)after ageing.展开更多
Contact glow discharge electrolysis (CGDE) of o-chlorophenol (2-CP) was investigated under different pH, voltages and initial concentrations. And the mechanism of the oxidation was explored. The results suggested that...Contact glow discharge electrolysis (CGDE) of o-chlorophenol (2-CP) was investigated under different pH, voltages and initial concentrations. And the mechanism of the oxidation was explored. The results suggested that the degradation followed the first order kinetic law; Fe2+ had a remarkable catalytic effect on the removal rate of o-chloropenol. In the presence of Fe2+, 2-CP underwent an exhaustive degradation, from which the major intermediates included o-dihydroxybenze, p-hydroxybenze, p-benzoquione and carboxlic acids.展开更多
A series of metal oxide catalysts for catalytic oxidative degradation of 2-chlorophenol (2-CP) and 4-chlorophenol (4-CP) were prepared, and the supported CuO catalysts were studied particularly. The supported CuO ...A series of metal oxide catalysts for catalytic oxidative degradation of 2-chlorophenol (2-CP) and 4-chlorophenol (4-CP) were prepared, and the supported CuO catalysts were studied particularly. The supported CuO catalysts were characterized by XRD and NH3-TPD techniques, in which CuO/γ-Al2O3 exhibited high degradation activity. The addition of Na2O or K2O into CuO/γ-Al2O3 improved the oxidative degradation of CPs remarkably, in which Na2O was more efficient than K2O. Over CuO/γ-Al2O3-Na2O, CPs were completely converted and the liberation of the inorganic chloride from 2-CP or 4-CP reached 97% or 100% respectively at 30 ?C for 2 h. The supported CuO catalysts with good dispersion of CuO particles and less acid sites were favorable for the efficient oxidative degradation of CPs. In addition, the initial pH of the reaction solution was found to be an important factor which influenced the catalytic oxidative degradation of CPs and the initial pH of 11.2 and 9.8 was preferred for the oxidative degradation of 2-CP and 4-CP respectively over CuO/γ-Al2O3 catalyst.展开更多
In order to evaluate the thermal oxidation degradation behavior of lubricant with different antioxidants,the thermal kinetics equation based on the anlyses of thermogravimetry(TG),differential thermal analysis(DTA),an...In order to evaluate the thermal oxidation degradation behavior of lubricant with different antioxidants,the thermal kinetics equation based on the anlyses of thermogravimetry(TG),differential thermal analysis(DTA),and differential scanning calorimetry(DSC)was established,respectively,to calculate the activation energy of lubricant thermal-oxidative reaction.The thermal analyses of TG and DTA were employed to determine the thermal decomposition properties of ester oils trimethylolpropane trioleate(TMPTO)with butyl-octyl-diphenylamine/octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanoate/amine-phenol combination antioxidant.The activation energy of the lubricating oil adding antioxidant is increased relative to the TMPTO base oil,and the order of activation energy are Ec(93.732 kJ·mol^(-1))>Ed(88.71 kJ·mol^(-1))>Eb(58.41 kJ·mol^(-1))>Ea(46.32 kJ·mol^(-1)).The experimental results show that octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanoate in TMPTO has favorable resistance to thermal oxidation and decomposition.The thermal analysis method of DSC accurately reflects the heat exchange of lubricant thermal-oxidative reaction.The order of activation energy is calculated to ED(144.385 kJ·mol^(-1))>EC(110.05 kJ·mol^(-1))>EB(97.187 kJ·mol^(-1))>EA(66.02 kJ·mol^(-1)).It is illustrated that the amine-phenol combination antioxidant has the best thermal oxidation resistance,which is the same as what the oxidation onset temperature effected.展开更多
Degradation of dyes is an important environmental issue. In order to avoid the carcinogenic risks in anaerobic-aerobic biological process for wastewater containing azo dyes, a hemin based biomimetic oxidative degradat...Degradation of dyes is an important environmental issue. In order to avoid the carcinogenic risks in anaerobic-aerobic biological process for wastewater containing azo dyes, a hemin based biomimetic oxidative degradation of azo dyes was developed. Acid orange 7 (AO7) was selected as the model for azo dye and the high efficient degradation was achieved in hemin/H2O2 system at pH 11.0. Degradation could be described by a pseudo-first-order kinetic model. The order of dependence on H2O2 concentration was significantly larger than that of hemin. Coexisting anions sulphate and chloride had little effect on the degradation, but reductive sulphite dramatically inhibited the degradation. The protic solvent 2-prophanol obviously promoted the degradation. Azo chromogenic group was destroyed quickly and some smaller intermediates formed. Active species oxoferryl porphyrin p-cation radical +PFeIV=O generated from heterolytic cleavage of O-O in H2O2 catalyzed by hemin play the main roles in degradation and reaction pathways were proposed.展开更多
Thermal and thermo-oxidative decomposition and decomposition kinetics of flame retardant high impact polystyrene (HIPS) with triphenyl phosphate (TPP) and novolac type epoxy resin (NE) were characterized using t...Thermal and thermo-oxidative decomposition and decomposition kinetics of flame retardant high impact polystyrene (HIPS) with triphenyl phosphate (TPP) and novolac type epoxy resin (NE) were characterized using thermo-gravimetric experiment. And the flammability was determined by limited oxygen indices (LOI). The LOI results show that TPP and NE had a good synthetic effect on the flame retardancy of HIPS. Compared with pure HIPS, the LOI values of HIPS/NE and HIPS/TPP only increased by about 5%, and the LOI value of HIPS/TPP/NE reached 42.3%, nearly 23% above that of HIPS. All materials showed one main decomposition step, as radical HIPS scission predominated during anaerobic decomposition. TPP increased the activity energy effectively while NE affected the thermal-oxidative degradation more with the help of the char formation. With both TPP and NE, the materials could have a comparable good result of both thermal and thermal-oxidative degradation, which could contribute to their effect on the flame retardancy.展开更多
2,4,6-trichlorophenol (TCP) was firstly treated with air ions generated by electric discharge, and high dechlorination (53%) was observed after 60 min treatment, indicating that air ions are an efficient dechlorinatio...2,4,6-trichlorophenol (TCP) was firstly treated with air ions generated by electric discharge, and high dechlorination (53%) was observed after 60 min treatment, indicating that air ions are an efficient dechlorination means and might have a future in the oxidative removal of chlorinated phenols. In addition, a stepwise degradation of TCP, beginning with the formation of a major product 2,6-dichloro-1,4-benzenediol via substitution, is proposed through a detailed analysis of gas chromatography/mass spectrometry.展开更多
Treatment of biliverdin IXα dimethyl ester(2)with silver nitrate in alkaline solution gave two violin-like tripyrrione carbaldehydes,one de- graded at C15-C16,other at C4-C5.Biliverdin IXα(1),bilirubin IXα(3)and it...Treatment of biliverdin IXα dimethyl ester(2)with silver nitrate in alkaline solution gave two violin-like tripyrrione carbaldehydes,one de- graded at C15-C16,other at C4-C5.Biliverdin IXα(1),bilirubin IXα(3)and its dimethyl ester(4)gave the same results.展开更多
In order to minimize the hot-carrier effect(HCE)and maintain on-state performance in the high voltage N-type lateral double diffused MOS(N-LDMOS), an optimized device structure with step gate oxide is proposed. Co...In order to minimize the hot-carrier effect(HCE)and maintain on-state performance in the high voltage N-type lateral double diffused MOS(N-LDMOS), an optimized device structure with step gate oxide is proposed. Compared with the conventional configuration, the electric field under the gate along the Si-SiO2 interface in the presented N-LDMOS can be greatly reduced, which favors reducing the hot-carrier degradation. The step gate oxide can be achieved by double gate oxide growth, which is commonly used in some smart power ICs. The differences in hot-carrier degradations between the novel structure and the conventional structure are investigated and analyzed by 2D technology computer-aided design(TCAD)numerical simulations, and the optimal length of the thick gate oxide part in the novel N-LDMOS device can also be acquired on the basis of maintaining the characteristic parameters of the conventional device. Finally, the practical degradation measurements of some characteristic parameters can also be carried out. It is found that the hot-carrier degradation of the novel N-LDMOS device can be improved greatly.展开更多
The generation of oxide charge for 4nm pMOSFETs under hot-carrier stress is investigated by the charge pumping measurements.Firstly,the direct experimental evidences of logarithmic time dependence of hole trapping is ...The generation of oxide charge for 4nm pMOSFETs under hot-carrier stress is investigated by the charge pumping measurements.Firstly,the direct experimental evidences of logarithmic time dependence of hole trapping is observed for pMOSFETs with different channel lengths under hot-carrier stress.Thus,the relationships of oxide charge generation,including electron trapping and hole trapping effects,with different stress voltages and channel lengths are analyzed.It is also found that there is a two-step process in the generation of oxide charge for pMOSFETs.For a short stress time,electron trapping is predominant,whereas for a long stress time,hole trapping dominates the generation of oxide charge.展开更多
基金supported by the Program for the National Natural Science Foundation of China(52070077,51879101,51779090)the National Program for Support of Top-Notch Young Professionals of China(2014)+1 种基金the Program for Changjiang Scholars and Innovative Research Team in University(IRT-13R17)Natural Science Foundation of Hunan Province(2022JJ20013,2021JJ40098).
文摘Carbon-doped copper ferrite(C–CuFe_(2)O_(4))was synthesized by a simple two-step hydrothermal method,which showed enhanced tetracycline hydrochloride(TCH)removal efficiency as compared to the pure CuFe_(2)O_(4) in Fenton-like reaction.A removal efficiency of 94%was achieved with 0.2 g L^(-1) catalyst and 20 mmol L^(-1) H_(2)O_(2) within 90 min.We demonstrated that 5%C–CuFe_(2)O_(4) catalyst in the presence of H_(2)O_(2) was significantly efficient for TCH degradation under the near-neutral pH(5–9)without buffer.Multiple techniques,including SEM,TEM,XRD,FTIR,Raman,XPS M€ossbauer and so on,were conducted to investigate the structures,morphologies and electronic properties of as-prepared samples.The introduction of carbon can effectively accelerate electron transfer by cooperating with Cu and Fe to activate H_(2)O_(2) to generate·OH and·O_(2)^(-).Particularly,theoretical calculations display that the p,p,d orbital hybridization of C,O,Cu and Fe can form C–O–Cu and C–O–Fe bonds,and the electrons on carbon can transfer to metal Cu and Fe along the C–O–Fe and C–O–Cu channels,thus forming electron-rich reactive centers around Fe and Cu.This work provides lightful reference for the modification of spinel ferrites in Fenton-like application.
基金the National Key R&D Program of China(No.2018YFB1502201)the Guangdong Basic and Applied Basic Research Foundation,China(No.2020A1515010551).
文摘For present solid oxide fuel cells(SOFCs),rapid performance degradation is observed in the initial aging process,and the dis-cussion of the degradation mechanism necessitates quantitative analysis.Herein,focused ion beam-scanning electron microscopy was em-ployed to characterize and reconstruct the ceramic microstructures of SOFC anodes.The lattice Boltzmann method(LBM)simulation of multiphysical and electrochemical processes in the reconstructed models was performed.Two samples collected from industrial-size cells were characterized,including a reduced reference cell and a cell with an initial aging process.Statistical parameters of the reconstructed microstructures revealed a significant decrease in the active triple-phase boundary and Ni connectivity in the aged cell compared with the reference cell.The LBM simulation revealed that activity degradation is dominant compared with microstructural degradation during the initial aging process,and the electrochemical reactions spread to the support layer in the aged cell.The microstructural and activity de-gradations are attributed to Ni migration and coarsening.
基金National Natural Science Foundation of China(Grant No.21902001,22179001)Distinguished Young Research Project of Anhui Higher Education Institution(Grant No.2022AH020007)+1 种基金University Synergy Innovation Program of Anhui Province(Grant No.GXXT-2023-009)Higher Education Natural Science Foundation of Anhui Province(Grant No.2023AH050114).
文摘Adsorption coupled with photocatalytic degradation is proposed to fulfill the removal and thorough elimination of organic dyes.Herein,we report a facile hydrothermal synthesis of MIL-100(Fe)/GO photocatalysts.The adsorption and photocatalytic degradation process of methylene blue(MB)on MIL‐100(Fe)/GO composites were systematically studied from performance and kinetic perspectives.A possible adsorption‐photocatalytic degradation mechanism is proposed.The optimized 1M8G composite achieves 95%MB removal(60.8 mg/g)in 210 min and displays well recyclability over ten cycles.The obtained MB adsorption and degradation results are well fitted onto Langmuir isotherm and pseudo‐second order kinetic model.This study shed light on the design of MOFs based composites for water treatment.
基金supported by the National Natural Science Foundation of China(51268001)~~
文摘A novel iron-glutamate-silicotungstate ternary complex(FeШGluS iW) was synthesized from ferric chloride(FeI II),glutamic acid(Glu),and silicotungstic acid(SiW),and used as a heterogeneous Fenton-like catalyst for 4-chlorophenol(4-CP) degradation at neutral pH value. The prepared FeШGluS iW was characterized using inductively coupled plasma atomic emission spectroscopy,thermogravimetry,Fourier-transform infrared spectroscopy,ultraviolet-visible diffuse reflectance spectroscopy,X-ray diffraction,and field-emission scanning electron microscopy. The results showed that FeШGluS iW has the formula [Fe(C5H8NO4)(H2O)]2SiW 12O40?13H2O,with glutamate moiety and Keggin-structured SiW 12O404- heteropolyanion. The catalyst showed high catalytic activity in 4-CP degradation in the dark and under irradiation. Under the conditions of 4-CP 100 mg/L,FeШGluS iW 1.0 g/L,H2O2 20 mmol/L,and pH = 6.5,4-CP was completely decomposed in 40 min in the dark and in 15 min under irradiation. When the reaction time was prolonged to 2 h,the corresponding total organic carbon removals under dark and irradiated conditions were ca. 27% and 72%,respectively. The high catalytic activity of FeI IIGluS iW is resulted from hydrogen bonding of H2O2 on the FeI IIGluS iW surface. The enhanced degradation of 4-CP under irradiation arises from simultaneous oxidation of 4-CP through Fenton-like and photocatalytic processes respectively catalyzed by ferric iron and the SiW 12O404- hetropolyanion in FeШGluS iW.
基金supported by the Guangdong Provincial Science and Technology Commission,Guangdong Key Areas R&D Program(2020B0909030004)the Beijing Natural Science Foundation Committee,Haidian Original Innovation Joint Fund Project(L182023)Youth Fund Project of GRINM(Grant No.12620203129011).
文摘Lithium-rich layered oxides(LLOs)are promising candidate cathode materials for safe and inexpensive high-energy-density Li-ion batteries.However,oxygen dimers are formed from the cathode material through oxygen redox activity,which can result in morphological changes and structural transitions that cause performance deterioration and safety concerns.Herein,a flake-like LLO is prepared and aberration-corrected scanning transmission electron microscopy(STEM),in situ high-temperature X-ray diffraction(HT-XRD),and soft X-ray absorption spectrum(sXAS)are used to explore its crystal facet degradation behavior in terms of both thermal and electrochemical processes.Void-induced degradation behavior of LLO in different facet reveals significant anisotropy at high voltage.Particle degradation originates from side facets,such as the(010)facet,while the close(003)facet is stable.These results are further understood through ab initio molecular dynamics calculations,which show that oxygen atoms are lost from the{010}facets.Therefore,the facet degradation process is that oxygen molecular formed in the interlayer and accumulated in the ab plane during heating,which result in crevice-voids in the ab plane facets.The study reveals important aspects of the mechanism responsible for oxygen-anionic activity-based degradation of LLO cathode materials used in lithium-ion batteries.In particular,this study provides insight that enables precise and efficient measures to be taken to improve the thermal and electrochemical stability of an LLO.
基金supported by the Research and Development Institute at Nakhon Si Thammarat Rajabhat University and the Nanomaterials Chemistry Research Unit at Nakhon Si Thammarat Rajabhat University,Nakhon Si Thammarat,Thailand(Grant No.004/2563).
文摘In this paper, we present a proof-of-concept study of the enhancement of photocatalytic activity via a combined strategy of fabricating a visible-light responsive ternary heterostructure and improving overall photostability by incorporating magnetic zinc oxide/graphene/iron oxide (ZGF). A solvothermal approach was used to synthesize the catalyst. X-ray diffraction (XRD), scanning electron microscopic, energy dispersive X-ray, transmission electron microscopic, vibrating sample magnetometric, and ultraviolet–visible diffuse reflectance spectroscopic techniques were used to characterize the synthesized samples. The obtained optimal Zn(NO_(3))_(2) concentration, temperature, and heating duration were 0.10 mol/L, 600℃, and 1 h, respectively. The XRD pattern revealed the presence of peaks corresponding to zinc oxide, graphene, and iron oxide, indicating that the ZGF catalyst was effectively synthesized. Furthermore, when the developed ZGF was used for methylene blue dye degradation, the optimum irradiation time, dye concentration, catalyst dosage, irradiation intensity, and solution pH were 90 min, 10 mg/L, 0.03 g/L, 100 W, and 8.0, respectively. Therefore, the synthesized ZGF system could be used as a catalyst to degrade dyes in wastewater samples. This hybrid nanocomposite consisting of zinc oxide, graphene, and iron oxide could also be used as an effective photocatalytic degrader for various dye pollutants.
基金Supported by the National Natural Science Foundation of China(20876064) the Natural Science Foundation of Guangdong Province(9151064101000082) the Guangdong Provincial International Cooperation Fund(2008B05010006)
文摘The effects of oxidant dosage,oxidation temperature and time on the degradation of soda lignin by hydrogen peroxide with and without the presence of microwave irradiation were investigated.It is found that the oxidative degradation of lignin includes the cleavage of ether bond inβ-O-4 structure,the partial destruction of aromatic ring,and the re-condensation of the degraded lignin.Compared to the conventionally heated oxidation of lignin,the microwave irradiation efficiently facilitates the degradation of the lignin with high molecular weight and the re-condensation of that with low molecular weight at a low oxidant dosage,low oxidation temperature,or a short oxidation time,which leads to the formation of the degraded lignin with narrower molecular weight distribution and lower molecular weight.Additionally,the lignin degraded in the presence of microwave irradiation has the characteristics of higher content of phenolic hydroxyl group,lower content of methoxyl group,and lower degree of condensation,which enhances the reactivity of lignin.Therefore,the oxidative degradation of lignin assisted by microwave irradiation may be a new pretreatment approach for efficiently utilizing the soda lignin.
文摘The study focused on the application of high-resolution mass spectrometry for the identification of impurities in pharmaceutical small molecules. A high-performance liquid chromatography (HPLC) coupled high resolution mass spectrometer (HRMS) was used for identification of oxidative degradation impurities (DIs) of lansoprazole. The utilization of HRMS facilitates to determine the accurate mass of impurities and their fragment/product ions. A fast mass spectrometer (MS) compatible reverse phase chromatography method was used to investigate the oxidative stressed impurities. HPLC column;C18 (50 × 4.6 mm, 3.5 μm) was used with gradient elution. Spectral data acquired using information dependent acquisition (IDA) with real time dynamic background subtraction algorithm (DBS). Three oxidative impurities: DI-I (m/z 386.0781), DI-II (m/z 402.0734) and DI-III (m/z 386.0785), was observed during this study;interpretation of high resolution spectral data of all three impurities was carried out;elemental composition and molecular structure was proposed for major fragments. In this study mass error was found ≤7.7 parts per million (ppm).
文摘A fully characterised natural rubber latex was subjected to mechanical degradation by stirring at intervals. The resistance to oxidative degradation of the different samples were studied by measuring the Plasticity retention indices (PRI). The results show that there is an enhancement of the PRI from 57% for the undegraded rubber to 79% for the one-hour degraded sample. Further degradation resulted in decrease of PRI as time of degradation increased. Therefore, the one-hour degraded sample is a special rubber with high oxidation resistance which is of great importance in engineering. (Author abstract) 9 Refs.
基金the National Natural Science Foundation of China.
文摘Iron-doped titania nanoparticles exhibit a higher photocatalytic activity than pure TiO_2 for the degradation of nitrite. The optimum Fe-doped content in terms of activity is approximately 0.5%. The increase in photoactivity is probably due to the higher adsorption and the inhibition of electron-hole recombination. The photocatalytic oxidation reaction of nitrite over the Fe-doped TiO_2 catalyst follows zero-order kinetics, which is different from that over pure TiO_2. The reaction rate decreases linearly with the increase of the pH of the solution.
基金supported by the Key Special Program on the S&T for the Pollution Control and Treatment of Water Bodies (No.2017ZX07603-003)。
文摘The natural attapulgite(NAPT)was disaggregated by high-pressure homogenization technology combined with extrusion process to prepare the attapulgite with disaggregated rod crystal bundles(DAPT)and large specific surface area of 133.7 m^(2)/g.NAPT and DAPT were incorporated into the silicone rubber to obtain the composite NAPTSR and DAPT-SR by mechanical blending method,respectively.After thermal oxidative ageing at 300℃ for 0.5 h,temperature for the 5%weight loss increased greatly from 385℃ of the neat silicone rubber to 396-399℃ with addition of NAPT and DAPT.NAPT and DAPT enhanced the interaction between the filler nanoparticles and rubber matrix thus inhibited the nanoparticle agglomeration.The conservation rate of the side methyl group in NAPT-SR and DAPT-SR was greatly improved after ageing.Therefore,the thermal oxidative degradation and ageing performance of the silicone rubber composites was significantly reinforced.Moreover,DAPT could greatly restrain the growth of nanoparticles after ageing.Therefore,DAPT-SR showed the better retention of tensile strength(40.6%),elongation at break(34.9%)and tear strength(30.1%)compared with the corresponding mechanical properties of the neat silicone rubber(10.6%,7.4%,and 5.0%)after ageing.
基金The project supported by the Key Project of Science and Technology from the Ministry of Education China (No. 00250) the project of KJCXGC-01 of Northwest Normal University, China
文摘Contact glow discharge electrolysis (CGDE) of o-chlorophenol (2-CP) was investigated under different pH, voltages and initial concentrations. And the mechanism of the oxidation was explored. The results suggested that the degradation followed the first order kinetic law; Fe2+ had a remarkable catalytic effect on the removal rate of o-chloropenol. In the presence of Fe2+, 2-CP underwent an exhaustive degradation, from which the major intermediates included o-dihydroxybenze, p-hydroxybenze, p-benzoquione and carboxlic acids.
基金financially supported by the Education Department of Liaoning Province(No.2009A421)
文摘A series of metal oxide catalysts for catalytic oxidative degradation of 2-chlorophenol (2-CP) and 4-chlorophenol (4-CP) were prepared, and the supported CuO catalysts were studied particularly. The supported CuO catalysts were characterized by XRD and NH3-TPD techniques, in which CuO/γ-Al2O3 exhibited high degradation activity. The addition of Na2O or K2O into CuO/γ-Al2O3 improved the oxidative degradation of CPs remarkably, in which Na2O was more efficient than K2O. Over CuO/γ-Al2O3-Na2O, CPs were completely converted and the liberation of the inorganic chloride from 2-CP or 4-CP reached 97% or 100% respectively at 30 ?C for 2 h. The supported CuO catalysts with good dispersion of CuO particles and less acid sites were favorable for the efficient oxidative degradation of CPs. In addition, the initial pH of the reaction solution was found to be an important factor which influenced the catalytic oxidative degradation of CPs and the initial pH of 11.2 and 9.8 was preferred for the oxidative degradation of 2-CP and 4-CP respectively over CuO/γ-Al2O3 catalyst.
基金Funded by the National Natural Science Foundation of China(52075391)the China Postdoctoral Science Foundation(2019M660596)。
文摘In order to evaluate the thermal oxidation degradation behavior of lubricant with different antioxidants,the thermal kinetics equation based on the anlyses of thermogravimetry(TG),differential thermal analysis(DTA),and differential scanning calorimetry(DSC)was established,respectively,to calculate the activation energy of lubricant thermal-oxidative reaction.The thermal analyses of TG and DTA were employed to determine the thermal decomposition properties of ester oils trimethylolpropane trioleate(TMPTO)with butyl-octyl-diphenylamine/octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanoate/amine-phenol combination antioxidant.The activation energy of the lubricating oil adding antioxidant is increased relative to the TMPTO base oil,and the order of activation energy are Ec(93.732 kJ·mol^(-1))>Ed(88.71 kJ·mol^(-1))>Eb(58.41 kJ·mol^(-1))>Ea(46.32 kJ·mol^(-1)).The experimental results show that octadecyl 3-(3,5-di-tert-butyl-4-hydroxyphenyl)propanoate in TMPTO has favorable resistance to thermal oxidation and decomposition.The thermal analysis method of DSC accurately reflects the heat exchange of lubricant thermal-oxidative reaction.The order of activation energy is calculated to ED(144.385 kJ·mol^(-1))>EC(110.05 kJ·mol^(-1))>EB(97.187 kJ·mol^(-1))>EA(66.02 kJ·mol^(-1)).It is illustrated that the amine-phenol combination antioxidant has the best thermal oxidation resistance,which is the same as what the oxidation onset temperature effected.
文摘Degradation of dyes is an important environmental issue. In order to avoid the carcinogenic risks in anaerobic-aerobic biological process for wastewater containing azo dyes, a hemin based biomimetic oxidative degradation of azo dyes was developed. Acid orange 7 (AO7) was selected as the model for azo dye and the high efficient degradation was achieved in hemin/H2O2 system at pH 11.0. Degradation could be described by a pseudo-first-order kinetic model. The order of dependence on H2O2 concentration was significantly larger than that of hemin. Coexisting anions sulphate and chloride had little effect on the degradation, but reductive sulphite dramatically inhibited the degradation. The protic solvent 2-prophanol obviously promoted the degradation. Azo chromogenic group was destroyed quickly and some smaller intermediates formed. Active species oxoferryl porphyrin p-cation radical +PFeIV=O generated from heterolytic cleavage of O-O in H2O2 catalyzed by hemin play the main roles in degradation and reaction pathways were proposed.
基金Guangdong Province Natural Sciences Fundation(No.39672)
文摘Thermal and thermo-oxidative decomposition and decomposition kinetics of flame retardant high impact polystyrene (HIPS) with triphenyl phosphate (TPP) and novolac type epoxy resin (NE) were characterized using thermo-gravimetric experiment. And the flammability was determined by limited oxygen indices (LOI). The LOI results show that TPP and NE had a good synthetic effect on the flame retardancy of HIPS. Compared with pure HIPS, the LOI values of HIPS/NE and HIPS/TPP only increased by about 5%, and the LOI value of HIPS/TPP/NE reached 42.3%, nearly 23% above that of HIPS. All materials showed one main decomposition step, as radical HIPS scission predominated during anaerobic decomposition. TPP increased the activity energy effectively while NE affected the thermal-oxidative degradation more with the help of the char formation. With both TPP and NE, the materials could have a comparable good result of both thermal and thermal-oxidative degradation, which could contribute to their effect on the flame retardancy.
基金the Alexander von Humboldt Foundation of Germany, and partly by the CAS and the NNSF of China.
文摘2,4,6-trichlorophenol (TCP) was firstly treated with air ions generated by electric discharge, and high dechlorination (53%) was observed after 60 min treatment, indicating that air ions are an efficient dechlorination means and might have a future in the oxidative removal of chlorinated phenols. In addition, a stepwise degradation of TCP, beginning with the formation of a major product 2,6-dichloro-1,4-benzenediol via substitution, is proposed through a detailed analysis of gas chromatography/mass spectrometry.
文摘Treatment of biliverdin IXα dimethyl ester(2)with silver nitrate in alkaline solution gave two violin-like tripyrrione carbaldehydes,one de- graded at C15-C16,other at C4-C5.Biliverdin IXα(1),bilirubin IXα(3)and its dimethyl ester(4)gave the same results.
基金The Natural Science Foundation of Jiangsu Province(No.BK2008287)the Preresearch Project of the National Natural Science Foundation of Southeast University(No.XJ2008312)
文摘In order to minimize the hot-carrier effect(HCE)and maintain on-state performance in the high voltage N-type lateral double diffused MOS(N-LDMOS), an optimized device structure with step gate oxide is proposed. Compared with the conventional configuration, the electric field under the gate along the Si-SiO2 interface in the presented N-LDMOS can be greatly reduced, which favors reducing the hot-carrier degradation. The step gate oxide can be achieved by double gate oxide growth, which is commonly used in some smart power ICs. The differences in hot-carrier degradations between the novel structure and the conventional structure are investigated and analyzed by 2D technology computer-aided design(TCAD)numerical simulations, and the optimal length of the thick gate oxide part in the novel N-LDMOS device can also be acquired on the basis of maintaining the characteristic parameters of the conventional device. Finally, the practical degradation measurements of some characteristic parameters can also be carried out. It is found that the hot-carrier degradation of the novel N-LDMOS device can be improved greatly.
文摘The generation of oxide charge for 4nm pMOSFETs under hot-carrier stress is investigated by the charge pumping measurements.Firstly,the direct experimental evidences of logarithmic time dependence of hole trapping is observed for pMOSFETs with different channel lengths under hot-carrier stress.Thus,the relationships of oxide charge generation,including electron trapping and hole trapping effects,with different stress voltages and channel lengths are analyzed.It is also found that there is a two-step process in the generation of oxide charge for pMOSFETs.For a short stress time,electron trapping is predominant,whereas for a long stress time,hole trapping dominates the generation of oxide charge.