The microstructural evolution of Cu−19Ni−6Cr−7Mn alloy during aging treatment was investigated.After aging for 120 min at 500℃,the alloy exhibited excellent mechanical properties,including a tensile strength of 978 M...The microstructural evolution of Cu−19Ni−6Cr−7Mn alloy during aging treatment was investigated.After aging for 120 min at 500℃,the alloy exhibited excellent mechanical properties,including a tensile strength of 978 MPa and an elastic modulus of 145.8 GPa.After aging for 240 min at 500℃,the elastic modulus of the alloy reached 149.5 GPa,which was among the highest values reported for Cu alloys.It was worth mentioning that the tensile strength increased rapidly from 740 to 934 MPa after aging for 5 min at 500℃,which was close to the maximum tensile strength(978 MPa).Analysis of the underlying strengthening mechanisms and phase transformation behavior revealed that the Cu−19Ni−6Cr−7Mn alloy underwent spinodal decomposition and DO_(22) ordering during the first 5 min of aging at 500℃,and L1_(2) ordered phases and bcc-Cr precipitates appeared.Therefore,the enhanced mechanical properties of the Cu−19Ni−6Cr−7Mn alloy can be attributed to the stress field generated by spinodal decomposition and the presence of nanoscale ordered phase and Cr precipitates.展开更多
Layered manganese dioxide(δ-MnO_(2))is a promising cathode material for aqueous zinc-ion batteries(AZIBs)due to its high theoretical capacity,high operating voltage,and low cost.However,its practical application face...Layered manganese dioxide(δ-MnO_(2))is a promising cathode material for aqueous zinc-ion batteries(AZIBs)due to its high theoretical capacity,high operating voltage,and low cost.However,its practical application faces challenges,such as low electronic conductivity,sluggish diffusion kinetics,and severe dissolution of Mn^(2+).In this study,we developed a δ-MnO_(2) coated with a 2-methylimidazole(δ-MnO_(2)@2-ML)hybrid cathode.Density functional theory(DFT)calculations indicate that 2-ML can be integrated into δ-MnO_(2) through both pre-intercalation and surface coating,with thermodynamically favorable outcomes.This modification expands the interlayer spacing of δ-MnO_(2) and generates Mn-N bonds on the surface,enhancing Zn^(2+)accommodation and diffusion kinetics as well as stabilizing surface Mn sites.The experimentally prepared δ-MnO_(2)@2-ML cathode,as predicted by DFT,features both 2-ML pre-intercalation and surface coating,providing more zinc-ion insertion sites and improved structural stability.Furthermore,X-ray diffraction shows the expanded interlayer spacing,which effectively buffers local electrostatic interactions,leading to an enhanced Zn^(2+)diffusion rate.Consequently,the optimized cathode(δ-MnO_(2)@2-ML)presents improved electrochemical performance and stability,and the fabricated AZIBs exhibit a high specific capacity(309.5mAh/g at 0.1 A/g),superior multiplicative performance(137.6mAh/g at 1 A/g),and impressive capacity retention(80%after 1350 cycles at 1 A/g).These results surpass the performance of most manganese-based and vanadium-based cathode materials reported to date.This dual-modulation strategy,combining interlayer engineering and interface optimization,offers a straightforward and scalable approach,potentially advancing the commercial viability of low-cost,high-performance AZIBs.展开更多
Two strains of Fe/Mn oxidizing bacteria tolerant to high concentrations of multiple heavy metal(loid)s and efficient decontamination for them were screened.The surface of the bio-Fe/Mn oxides produced by the oxidation...Two strains of Fe/Mn oxidizing bacteria tolerant to high concentrations of multiple heavy metal(loid)s and efficient decontamination for them were screened.The surface of the bio-Fe/Mn oxides produced by the oxidation of Fe(II)and Mn(II)by Pseudomonas taiwanensis(marked as P4)and Pseudomonas plecoglossicida(marked as G1)contains rich reactive oxygen functional groups,which play critical roles in the removal efficiency and immobilization of heavymetal(loid)s in co-contamination system.The isolated strains P4 and G1 can growwell in the following environments:pH 5-9,NaCl 0-4%,and temperature 20-30℃.The removal efficiencies of Fe,Pb,As,Zn,Cd,Cu,and Mn are effective after inoculation of the strains P4 and G1 in the simulated water system(the initial concentrations of heavy metal(loid)were 1 mg/L),approximately reaching 96%,92%,85%,67%,70%,54%and 15%,respectively.The exchangeable and carbonate bound As,Cd,Pb and Cu are more inclined to convert to the Fe-Mn oxide bound fractions in P4 and G1 treated soil,thereby reducing the phytoavailability and bioaccessible of heavy metal(loid)s.This research provides alternatives method to treat water and soil containing high concentrations of multi-heavy metal(loid)s.展开更多
Studies widely acknowledge the enhancement of permanganate(Mn(Ⅶ))oxidation of organic contaminants by coexisting matrices in water.This study investigated the positive influence of Mn(Ⅱ),a common soluble metal ion,o...Studies widely acknowledge the enhancement of permanganate(Mn(Ⅶ))oxidation of organic contaminants by coexisting matrices in water.This study investigated the positive influence of Mn(Ⅱ),a common soluble metal ion,on the removal of trace organic pollutants by Mn(Ⅶ).Results showed that introducing 20μmol/L Mn(Ⅱ)at pH 5.0 accelerated trace organic pollutant removal by promoting colloidal MnO_(2)formation.UV-vis spectrum,quenching,and probe experiments confirmed role of MnO_(2)in sulfamethoxazole(SMX)oxidation,with Mn(Ⅲ)playing a predominant role.Meanwhile,in situ-generated MnO_(2)facilitated Mn(Ⅶ)*formation,enhancing oxidation performance,as indicated by Raman spectroscopy and electrochemical analysis.Eleven transformation products(TPs)of SMX in the Mn(Ⅶ)/Mn(Ⅱ)process were detected by UPLC-QTOF-MS/MS.Subsequently,the reaction pathways of SMX were elucidated through Fukui index analysis and the identification of TPs.Additionally,toxicity simulations with Toxicity Estimation Software Tool(T.E.S.T.)software revealed significantly lower cytotoxicity of TPs of SMX compared to the parent compound.This study unveils an effective strategy to enhance Mn(Ⅶ)-mediated degradation of organic pollutants in water,elucidating Mn(Ⅱ)-induced Mn(Ⅶ)activation mechanisms.展开更多
Manganese dioxide(MnO_(2)),based on a two-electron-transfer deposition/dissolution chemistry,features an ultrahigh theoretical capacity(616 mAh·g^(−1)),a favorable redox potential(1.23 V vs.the standard hydrogen ...Manganese dioxide(MnO_(2)),based on a two-electron-transfer deposition/dissolution chemistry,features an ultrahigh theoretical capacity(616 mAh·g^(−1)),a favorable redox potential(1.23 V vs.the standard hydrogen electrode),inherent nontoxicity,and low cost,making it a promising cathode candidate for high-energy aqueous batteries.However,its practical application is hindered by limited electrochemical reversibility and cycling stability,primarily attributed to the formation and accumulation of electrochemically inactive Mn species commonly known as“dead Mn”.This perspective provides an in-depth analysis of the“dead Mn”dilemma inherent in Mn^(2+)/MnO_(2) chemistry.First,the fundamental causes of“dead Mn”—insufficient electron supply and imbalanced(insufficient or excessive)proton supply,are systematically analyzed,as they detract from active material utilization,cycle life,and energy density.Then,mitigation strategies are examined from three aspects:preventing“dead Mn”formation caused by insufficient electron supply,mitigating“dead Mn”formation related to imbalanced proton supply,and activating and regenerating existing“dead Mn”.Finally,future research directions are visualized to enhance the practical viability of Mn^(2+)/MnO_(2) deposition/dissolution chemistry,aiming to catalyze advancements in high-energy aqueous battery systems.展开更多
Mn^(2+)-doped CsPbCl_(3)(Mn^(2+):CsPbCl_(3)) nanocrystals(NCs) have attracted considerable attention due to their unique strong and broad orange-red emission band,presenting promising applications in the field of phot...Mn^(2+)-doped CsPbCl_(3)(Mn^(2+):CsPbCl_(3)) nanocrystals(NCs) have attracted considerable attention due to their unique strong and broad orange-red emission band,presenting promising applications in the field of photoelectric devices.However,pristine Mn^(2+):CsPbCl_(3)NCs commonly suffer from low photoluminescence quantum yield(PL QY) and stability issues.Herein,we introduced europium ions(Eu^(3+))into Mn^(2+):CsPbCl_(3)NCs via the thermal injection synthesis method to obtain high performance Eu^(3+)and Mn^(2+)codoped CsPbCl_(3)(Eu^(3+)/Mn^(2+):CsPbCl_(3)) NCs.The maximum PL QY of the resulting Eu^(3+)/Mn^(2+):CsPbCl_(3)NCs reaches up to 90.92%.It is found that the doping of Eu^(3+)ions significantly reduces the non-radiative recombination caused by high defect states,and improves the energy transfer efficiency from exciton to Mn^(2+),thereby boosting the PL performance.Moreover,doping Eu^(3+)ions notably improves the UV-light and water stability of Mn^(2+):CsPbCl_(3)NCs.We further demonstrate the application versatility of Eu^(3+)/Mn^(2+):CsPbCl_(3)NCs in white light emitting diodes(WLEDs) and optical anticounterfeiting applications.This work provides a valuable perspective for the attainment of high performance Mn^(2+):CsPbCl_(3)NCs and lays a foundation for the codoping of other lanthanide ions to adjust the luminescence properties of Mn^(2+):CsPbCl_(3)NCs.展开更多
Oxidative coupling of methane (OCM) is one of the most promising approaches to produce ethylene and ethane (C_(2)-hydrocarbons) in the post-oil era.The MnO_(x)-Na_(2)WO_(4)/SiO_(2) system shows promising OCM performan...Oxidative coupling of methane (OCM) is one of the most promising approaches to produce ethylene and ethane (C_(2)-hydrocarbons) in the post-oil era.The MnO_(x)-Na_(2)WO_(4)/SiO_(2) system shows promising OCM performance,which can be further enhanced by cofed steam.However,the positive effect of steam on C_(2)-hydrocarbons selectivity practically disappears above 800℃.In the present study,we demonstrate that the use of SiC as a support for MnO_(x)-Na_(2)WO_(4) is beneficial for achieving high selectivity up to 850℃.Our sophisticated kinetic tests using feeds without and with steam revealed that the steam-mediated improvement in selectivity to C_(2)-hydrocarbons is due to the inhibition of the direct CH_(4) oxidation to carbon oxides because of the different enhancing effects of steam on the rates of CH_(4) conversion to C_(2)H_(6) and CO/CO_(2).Other descriptors of the selectivity improvement are MnO_(x) dispersion and the catalyst specific surface area.The knowledge gained herein may be useful for optimizing OCM performance through catalyst design and reactor operation.展开更多
基金supported by the National Key R&D Program of China (No. 2021YFB3700700)the Henan Province Top Talent Training Program Project, China (No. 244500510020)the High-level Talent Research Start-up Project Funding of Henan Academy of Sciences, China (No. 242017001)。
文摘The microstructural evolution of Cu−19Ni−6Cr−7Mn alloy during aging treatment was investigated.After aging for 120 min at 500℃,the alloy exhibited excellent mechanical properties,including a tensile strength of 978 MPa and an elastic modulus of 145.8 GPa.After aging for 240 min at 500℃,the elastic modulus of the alloy reached 149.5 GPa,which was among the highest values reported for Cu alloys.It was worth mentioning that the tensile strength increased rapidly from 740 to 934 MPa after aging for 5 min at 500℃,which was close to the maximum tensile strength(978 MPa).Analysis of the underlying strengthening mechanisms and phase transformation behavior revealed that the Cu−19Ni−6Cr−7Mn alloy underwent spinodal decomposition and DO_(22) ordering during the first 5 min of aging at 500℃,and L1_(2) ordered phases and bcc-Cr precipitates appeared.Therefore,the enhanced mechanical properties of the Cu−19Ni−6Cr−7Mn alloy can be attributed to the stress field generated by spinodal decomposition and the presence of nanoscale ordered phase and Cr precipitates.
基金supported by the the National Natural Science Foundation of China(52203303)the Shenzhen Science and Technology Program(SGDX20211123151002003 and GJHZ20220913142812025)+1 种基金the International Partnership Program of the Chinese Academy of Sciences(321GJHZ2023189FN)the SIAT International Joint Lab(E5G108).
文摘Layered manganese dioxide(δ-MnO_(2))is a promising cathode material for aqueous zinc-ion batteries(AZIBs)due to its high theoretical capacity,high operating voltage,and low cost.However,its practical application faces challenges,such as low electronic conductivity,sluggish diffusion kinetics,and severe dissolution of Mn^(2+).In this study,we developed a δ-MnO_(2) coated with a 2-methylimidazole(δ-MnO_(2)@2-ML)hybrid cathode.Density functional theory(DFT)calculations indicate that 2-ML can be integrated into δ-MnO_(2) through both pre-intercalation and surface coating,with thermodynamically favorable outcomes.This modification expands the interlayer spacing of δ-MnO_(2) and generates Mn-N bonds on the surface,enhancing Zn^(2+)accommodation and diffusion kinetics as well as stabilizing surface Mn sites.The experimentally prepared δ-MnO_(2)@2-ML cathode,as predicted by DFT,features both 2-ML pre-intercalation and surface coating,providing more zinc-ion insertion sites and improved structural stability.Furthermore,X-ray diffraction shows the expanded interlayer spacing,which effectively buffers local electrostatic interactions,leading to an enhanced Zn^(2+)diffusion rate.Consequently,the optimized cathode(δ-MnO_(2)@2-ML)presents improved electrochemical performance and stability,and the fabricated AZIBs exhibit a high specific capacity(309.5mAh/g at 0.1 A/g),superior multiplicative performance(137.6mAh/g at 1 A/g),and impressive capacity retention(80%after 1350 cycles at 1 A/g).These results surpass the performance of most manganese-based and vanadium-based cathode materials reported to date.This dual-modulation strategy,combining interlayer engineering and interface optimization,offers a straightforward and scalable approach,potentially advancing the commercial viability of low-cost,high-performance AZIBs.
基金supported d by the National Key Research and Development Program of China(No.2018YFC1802905).
文摘Two strains of Fe/Mn oxidizing bacteria tolerant to high concentrations of multiple heavy metal(loid)s and efficient decontamination for them were screened.The surface of the bio-Fe/Mn oxides produced by the oxidation of Fe(II)and Mn(II)by Pseudomonas taiwanensis(marked as P4)and Pseudomonas plecoglossicida(marked as G1)contains rich reactive oxygen functional groups,which play critical roles in the removal efficiency and immobilization of heavymetal(loid)s in co-contamination system.The isolated strains P4 and G1 can growwell in the following environments:pH 5-9,NaCl 0-4%,and temperature 20-30℃.The removal efficiencies of Fe,Pb,As,Zn,Cd,Cu,and Mn are effective after inoculation of the strains P4 and G1 in the simulated water system(the initial concentrations of heavy metal(loid)were 1 mg/L),approximately reaching 96%,92%,85%,67%,70%,54%and 15%,respectively.The exchangeable and carbonate bound As,Cd,Pb and Cu are more inclined to convert to the Fe-Mn oxide bound fractions in P4 and G1 treated soil,thereby reducing the phytoavailability and bioaccessible of heavy metal(loid)s.This research provides alternatives method to treat water and soil containing high concentrations of multi-heavy metal(loid)s.
基金support from the National Natural Science Foundation of China(Nos.52300102,523B2094)the Key Laboratory of Jiangxi Province for Persistent Pollutants Prevention Control and Resource Reuse(No.2023SSY02061)+1 种基金the Natural Science Foundation of Sichuan Province(No.2024NSFSC0130)Miaozi Project in Science and Technology Innovation Program of Sichuan Province(No.MZGC20230098)。
文摘Studies widely acknowledge the enhancement of permanganate(Mn(Ⅶ))oxidation of organic contaminants by coexisting matrices in water.This study investigated the positive influence of Mn(Ⅱ),a common soluble metal ion,on the removal of trace organic pollutants by Mn(Ⅶ).Results showed that introducing 20μmol/L Mn(Ⅱ)at pH 5.0 accelerated trace organic pollutant removal by promoting colloidal MnO_(2)formation.UV-vis spectrum,quenching,and probe experiments confirmed role of MnO_(2)in sulfamethoxazole(SMX)oxidation,with Mn(Ⅲ)playing a predominant role.Meanwhile,in situ-generated MnO_(2)facilitated Mn(Ⅶ)*formation,enhancing oxidation performance,as indicated by Raman spectroscopy and electrochemical analysis.Eleven transformation products(TPs)of SMX in the Mn(Ⅶ)/Mn(Ⅱ)process were detected by UPLC-QTOF-MS/MS.Subsequently,the reaction pathways of SMX were elucidated through Fukui index analysis and the identification of TPs.Additionally,toxicity simulations with Toxicity Estimation Software Tool(T.E.S.T.)software revealed significantly lower cytotoxicity of TPs of SMX compared to the parent compound.This study unveils an effective strategy to enhance Mn(Ⅶ)-mediated degradation of organic pollutants in water,elucidating Mn(Ⅱ)-induced Mn(Ⅶ)activation mechanisms.
基金National Key Research and Development Program of China(Grant No.2022YFB2404500)the National Natural Science Foundation of China(Grant Nos.22479110,22109116 and 22121004)+3 种基金the Energy Revolution S&T Program of Yulin Innovation Institute of Clean Energy(Grant No.E411050316)the Natural Science Foundation of Tianjin(Grant No.23JCQNJC01750)the“Pandeng Plan”Project in Tianjin University(Grant No.2024XPD-0002)the Fundamental Research Funds for the Central Universities,and the Haihe Laboratory of Sustainable Chemical Transformations.
文摘Manganese dioxide(MnO_(2)),based on a two-electron-transfer deposition/dissolution chemistry,features an ultrahigh theoretical capacity(616 mAh·g^(−1)),a favorable redox potential(1.23 V vs.the standard hydrogen electrode),inherent nontoxicity,and low cost,making it a promising cathode candidate for high-energy aqueous batteries.However,its practical application is hindered by limited electrochemical reversibility and cycling stability,primarily attributed to the formation and accumulation of electrochemically inactive Mn species commonly known as“dead Mn”.This perspective provides an in-depth analysis of the“dead Mn”dilemma inherent in Mn^(2+)/MnO_(2) chemistry.First,the fundamental causes of“dead Mn”—insufficient electron supply and imbalanced(insufficient or excessive)proton supply,are systematically analyzed,as they detract from active material utilization,cycle life,and energy density.Then,mitigation strategies are examined from three aspects:preventing“dead Mn”formation caused by insufficient electron supply,mitigating“dead Mn”formation related to imbalanced proton supply,and activating and regenerating existing“dead Mn”.Finally,future research directions are visualized to enhance the practical viability of Mn^(2+)/MnO_(2) deposition/dissolution chemistry,aiming to catalyze advancements in high-energy aqueous battery systems.
基金Project supported by the National Natural Science Foundation of China (12174075)the Scientific and Technological Bases and Talents of Guangxi (Guike AD21220016)+1 种基金Guangxi Science and Technology Major Project(AA23073018)the special fund for Guangxi Bagui Scholars。
文摘Mn^(2+)-doped CsPbCl_(3)(Mn^(2+):CsPbCl_(3)) nanocrystals(NCs) have attracted considerable attention due to their unique strong and broad orange-red emission band,presenting promising applications in the field of photoelectric devices.However,pristine Mn^(2+):CsPbCl_(3)NCs commonly suffer from low photoluminescence quantum yield(PL QY) and stability issues.Herein,we introduced europium ions(Eu^(3+))into Mn^(2+):CsPbCl_(3)NCs via the thermal injection synthesis method to obtain high performance Eu^(3+)and Mn^(2+)codoped CsPbCl_(3)(Eu^(3+)/Mn^(2+):CsPbCl_(3)) NCs.The maximum PL QY of the resulting Eu^(3+)/Mn^(2+):CsPbCl_(3)NCs reaches up to 90.92%.It is found that the doping of Eu^(3+)ions significantly reduces the non-radiative recombination caused by high defect states,and improves the energy transfer efficiency from exciton to Mn^(2+),thereby boosting the PL performance.Moreover,doping Eu^(3+)ions notably improves the UV-light and water stability of Mn^(2+):CsPbCl_(3)NCs.We further demonstrate the application versatility of Eu^(3+)/Mn^(2+):CsPbCl_(3)NCs in white light emitting diodes(WLEDs) and optical anticounterfeiting applications.This work provides a valuable perspective for the attainment of high performance Mn^(2+):CsPbCl_(3)NCs and lays a foundation for the codoping of other lanthanide ions to adjust the luminescence properties of Mn^(2+):CsPbCl_(3)NCs.
基金supported by the National Key Research and Development Program (Nos.2020YFA0210903)the National Natural Science Foundation of China (Grant Nos.22225807,21961132026,22021004)DFG within joint Sino-German project (KO 2261/11-1)。
文摘Oxidative coupling of methane (OCM) is one of the most promising approaches to produce ethylene and ethane (C_(2)-hydrocarbons) in the post-oil era.The MnO_(x)-Na_(2)WO_(4)/SiO_(2) system shows promising OCM performance,which can be further enhanced by cofed steam.However,the positive effect of steam on C_(2)-hydrocarbons selectivity practically disappears above 800℃.In the present study,we demonstrate that the use of SiC as a support for MnO_(x)-Na_(2)WO_(4) is beneficial for achieving high selectivity up to 850℃.Our sophisticated kinetic tests using feeds without and with steam revealed that the steam-mediated improvement in selectivity to C_(2)-hydrocarbons is due to the inhibition of the direct CH_(4) oxidation to carbon oxides because of the different enhancing effects of steam on the rates of CH_(4) conversion to C_(2)H_(6) and CO/CO_(2).Other descriptors of the selectivity improvement are MnO_(x) dispersion and the catalyst specific surface area.The knowledge gained herein may be useful for optimizing OCM performance through catalyst design and reactor operation.
