Nanostructured iron sulfides are regarded as a potential anode material for sodium-ion batteries in virtue of the rich natural abundance and remarkable theoretical capacity.However,poor rate performance and inferior c...Nanostructured iron sulfides are regarded as a potential anode material for sodium-ion batteries in virtue of the rich natural abundance and remarkable theoretical capacity.However,poor rate performance and inferior cycling stability caused by sluggish kinetics and volume swelling represent two main obstacles at present. The previous research mainly focuses on nanostructure design and/or hybridizing with conductive materials.Further boosting the property by adjusting Fe/S atomic ratio in iron sulfides is rarely reported.In this work,Fe_7 S_8 and FeS_2 encapsulated in N-doped hollow carbon fibers(NHCFs/Fe_7 S_8 and NHCFs/FeS_2) are constructed by a combined chemical bath deposition and subsequent sulfidation treatment.The well-designed NHCFs/Fe_(7) S_(8) electrode displays a remarkable capacity of 517 mAh g^(-1) at 2 A g^(-1)after 1000 cycles and a superb rate capability with a capability of 444 mAh g^(-1) even at 20 A g^(-1) in etherbased electrolyte.Additionally,the rate capability of NHCFs/Fe_(7) S_(8) is superior to that of the contrast NHCFs/FeS_(2) electrode and also much better than the values of the most previously reported iron sulfide-based anodes.The in-depth mechanism explanation is explained by further experimental analysis and theoretical calculation,revealing Fe_(7) S_(8) displays improved intrinsic electronic conductivity and faster Na^(+) diffusion coefficient as well as higher reaction reversibility.展开更多
The extensive use of neonicotinoids on food crops for pest management has resulted in substantial environmental contamination.It is imperative to develop an effective remediation material and technique as well as to d...The extensive use of neonicotinoids on food crops for pest management has resulted in substantial environmental contamination.It is imperative to develop an effective remediation material and technique as well as to determine the evolution pathways of products.Here,novel ball-milled nitrogen-doped biochar(NBC)-modified zero-valent iron(ZVI)composites(named MNBC-ZVI)were fabricated and applied to degrading neonicotinoids.Based on the characterization results,NBC incorporation introduced N-doped sites and new allying heterojunctions and achieved surface charge redistribution,rapid electron transfer,and higher hydrophobicity of ZVI particles.As a result,the interaction between ZVI particles and thiamethoxam(a typical neonicotinoid)was improved,and the adsorption-desorption and reductive degradation of thiamethoxam and·H generation steps were optimized.MNBC-ZVI could rapidly degrade 100%of 10 mg·L^(−1) thiamethoxam within 360 min,its reduction rate constant was 12.1-fold greater than that of pristine ZVI,and the electron efficiency increased from 29.7%to 57.8%.This improved reactivity and selectivity resulted from increased electron transfer,enhanced hydrophobicity,and reduced accumulation of iron mud.Moreover,the degradation of neonicotinoids occurred mainly via nitrate reduction and dichlorination,and toxicity tests with degradation intermediates revealed that neonicotinoids undergo rapid detoxification.Remarkably,MNBCZVI also presented favorable tolerance to various anions,humic acid,wastewater and contaminated soil,as well as high reusability.This work offers an efficient and economic biochar-ZVI remediation technology for the rapid degradation and detoxification of neonicotinoids,significantly contributes to knowledge on the relevant removal mechanism and further advances the synthesis of highly reactive and environmentally friendly materials.展开更多
For zinc air batteries,a non-noble metal-based electrocatalyst with a high performance and stability in oxygen evolution reaction(OER)and oxygen reduction reaction(ORR)is imperative in application.Herein,a catalyst ba...For zinc air batteries,a non-noble metal-based electrocatalyst with a high performance and stability in oxygen evolution reaction(OER)and oxygen reduction reaction(ORR)is imperative in application.Herein,a catalyst based on FeCo-N encapsuled in nitrogen-doped carbon nanotubes has been prepared,which provides an implementable method to design controlled structures with excellent bifunction al electrocatalytic activities.By adjusting the molar ratio of two metals,the synthesized FeCo-N-C catalyst delivers a competitive ORR and OER performance compared with commercial Pt/C and IrO_(2),performing a low overvoltage gap between ORR(E_(1/2))and OER(E_(j=10))of 0.8 V.Moreover,as a promising cathode in zinc air battery,the FeCo-N-C catalyst possesses an affirmative stability of over 100 h and large power density(129 mW·cm^(-2)).This work demonstrates that FeCo-N-C is one of the most promising catalysts for zinc air batteries and provides a possibility for exploration of batteries with high stability by adjusting the molar ratio of metals in the catalysts.展开更多
A facile,gram-scale and sustainable approach has been established for the synthesis of single-atomic-site iron on N-doped carbon(Fe_(SA)@NC-20A)via the pyrolysis of aniline modified FeZn-ZIFs,in which the synthesis of...A facile,gram-scale and sustainable approach has been established for the synthesis of single-atomic-site iron on N-doped carbon(Fe_(SA)@NC-20A)via the pyrolysis of aniline modified FeZn-ZIFs,in which the synthesis of zeolitic imidazolate frameworks(ZIFs)can be accomplished in water at room temperature,and no acid etching is required.The as-synthesized catalyst exhibits better performance on the chemoselective hydrogenation of nitroarenes with a broad substrate scope(turnover frequency(TOF)up to 1,727 h^(-1),23 examples)than most of previously reported works.Based on high-angle annular dark field scanning transmission microscopy(HAADF-STEM)images in combination with X-ray photoelectron spectroscopy(XPS),X-ray absorption spectroscopy(XAS),electron spin resonance(ESR),and Mossbauer spectroscopy,Fe is dispersed as single atoms via forming FeNx(x=4-6).This work not only determines the active sites of FesA@NC-20A for hydrogenation(FeN4),but also proposes tentative pathways for both N-H activation of hydrazine and the reduction of nitroarene on FeN4 site,both of which are the key steps for the hydrogenation of nitroarenes.In addition,this catalyst shows excellent stability,and no significant activity degradation is observed when recycling for 10 times or restoring in air for 2 months.展开更多
The undesirable shuttle effect and sluggish redox kinetics of polysulfides seriously result in low sulfur utilization and poor capacity retention.Here,an integrated strategy is proposed by rational designing multifunc...The undesirable shuttle effect and sluggish redox kinetics of polysulfides seriously result in low sulfur utilization and poor capacity retention.Here,an integrated strategy is proposed by rational designing multifunctional architecture to manipulate the redox kinetics of polysulfides,specifically,by employing iron atoms(Fe-As)and iron-species nanoparticles(Fe-NPs)co-embedded nitrogen-doped carbon nanotube(Fe-NCNT)as catalyst and host for sulfur.The synergistic cooperation of Fe-As and Fe-NPs provides efficient active sites to facilitate the diffusion,strengthen the affinities,and promote the conversion reactions for polysulfides.Furthermore,the NCNT not only offers practical Li+transport pathways but also immobilize the polysulfides effectively.Benefiting from these merits,the Fe-NCNT/S electrodes exhibit high initial specific capacity of 1502.6 mAh/g at 0.1 C,outstanding rate performance(830 mAh/g at 2 C),and good cycling performance(597.8 mAh/g after 500 cycles with an ultralow capacity fading rate of 0.069%per cycle).This work features the distinct interaction of iron atom-nanoparticles on facilitating immobilization-diffusion-transformation process of polysulfides,and it also expected to pave the way for the application in practical Li-S batteries.展开更多
Ibuprofen(IBU),a nonsteroidal anti-inflammatory drug,is becoming an important member of pharmaceuticals and personal care products(PPCPs)as emerging pollutants.To degrade IBU,magnetic Fe_3C nanoparticles embedded on N...Ibuprofen(IBU),a nonsteroidal anti-inflammatory drug,is becoming an important member of pharmaceuticals and personal care products(PPCPs)as emerging pollutants.To degrade IBU,magnetic Fe_3C nanoparticles embedded on N-doped carbon(Fe_3C/NC)were prepared as a catalyst by a sol–gel combustion method.As characterized,the Fe_3C/NC nanoparticles were composed of a NC nano-sheet and capsulated Fe_3C particles on the sheet.The Fe_3C/NC nanoparticles were confirmed an efficient catalyst for peroxymonosulfate(PMS)activation to generate sulfate radicals(SO_4^(·-)),single oxygen(~1O_2)and hydroxyl radicals(·OH)toward the degradation of IBU.The added IBU(10 mg/L)was almost completely removed in 30 min by using 0.1 g/L Fe_3C/NC and 2 g/L PMS.The catalyst was confirmed to have good ability and excellent reusability through leaching measurements and cycle experiments.A catalytic mechanism was proposed for the catalytic activation of PMS on Fe_3C/NC,which involves both Fe_3C reactive sites and N-doped carbon matrix as reactive sites in Fe_3C/NC.Moreover,the degradation pathway of IBU in the Fe_3C/NC-PMS system was proposed according to the detections of degradation intermediates.展开更多
基金financial support from the National Natural Science Foundation of China (Grant No. 51702095)the Natural Science Foundation of Hunan Province, China (Grant No. 2018JJ3041, 2018JJ3042)the funding of State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body in Hunan University (No. 51965010)。
文摘Nanostructured iron sulfides are regarded as a potential anode material for sodium-ion batteries in virtue of the rich natural abundance and remarkable theoretical capacity.However,poor rate performance and inferior cycling stability caused by sluggish kinetics and volume swelling represent two main obstacles at present. The previous research mainly focuses on nanostructure design and/or hybridizing with conductive materials.Further boosting the property by adjusting Fe/S atomic ratio in iron sulfides is rarely reported.In this work,Fe_7 S_8 and FeS_2 encapsulated in N-doped hollow carbon fibers(NHCFs/Fe_7 S_8 and NHCFs/FeS_2) are constructed by a combined chemical bath deposition and subsequent sulfidation treatment.The well-designed NHCFs/Fe_(7) S_(8) electrode displays a remarkable capacity of 517 mAh g^(-1) at 2 A g^(-1)after 1000 cycles and a superb rate capability with a capability of 444 mAh g^(-1) even at 20 A g^(-1) in etherbased electrolyte.Additionally,the rate capability of NHCFs/Fe_(7) S_(8) is superior to that of the contrast NHCFs/FeS_(2) electrode and also much better than the values of the most previously reported iron sulfide-based anodes.The in-depth mechanism explanation is explained by further experimental analysis and theoretical calculation,revealing Fe_(7) S_(8) displays improved intrinsic electronic conductivity and faster Na^(+) diffusion coefficient as well as higher reaction reversibility.
基金National Natural Science Foundation of China(Nos.U21A20291,42377384)National Key R&D Program of China(No.2021YFD1000500)Major Research Plan of the Shandong Science Foundation(No.ZR2020ZD19).
文摘The extensive use of neonicotinoids on food crops for pest management has resulted in substantial environmental contamination.It is imperative to develop an effective remediation material and technique as well as to determine the evolution pathways of products.Here,novel ball-milled nitrogen-doped biochar(NBC)-modified zero-valent iron(ZVI)composites(named MNBC-ZVI)were fabricated and applied to degrading neonicotinoids.Based on the characterization results,NBC incorporation introduced N-doped sites and new allying heterojunctions and achieved surface charge redistribution,rapid electron transfer,and higher hydrophobicity of ZVI particles.As a result,the interaction between ZVI particles and thiamethoxam(a typical neonicotinoid)was improved,and the adsorption-desorption and reductive degradation of thiamethoxam and·H generation steps were optimized.MNBC-ZVI could rapidly degrade 100%of 10 mg·L^(−1) thiamethoxam within 360 min,its reduction rate constant was 12.1-fold greater than that of pristine ZVI,and the electron efficiency increased from 29.7%to 57.8%.This improved reactivity and selectivity resulted from increased electron transfer,enhanced hydrophobicity,and reduced accumulation of iron mud.Moreover,the degradation of neonicotinoids occurred mainly via nitrate reduction and dichlorination,and toxicity tests with degradation intermediates revealed that neonicotinoids undergo rapid detoxification.Remarkably,MNBCZVI also presented favorable tolerance to various anions,humic acid,wastewater and contaminated soil,as well as high reusability.This work offers an efficient and economic biochar-ZVI remediation technology for the rapid degradation and detoxification of neonicotinoids,significantly contributes to knowledge on the relevant removal mechanism and further advances the synthesis of highly reactive and environmentally friendly materials.
基金financially supported by Gansu Provincial Natural Science Foundation of China(Nos.17JR5RA198,2020HZ-2)the Cooperation project of Gansu Academy of Sciences(No.2020HZ-2)+1 种基金the Fundamental Research Funds for the Central Universities(Nos.lzujbky-2018-119,lzujbky-2018-ct08,lzujbky-2019-it23)the Key Areas Scientific and Technological Research Projects in Xinjiang Production and Construction Corps(No.2018AB004)。
文摘For zinc air batteries,a non-noble metal-based electrocatalyst with a high performance and stability in oxygen evolution reaction(OER)and oxygen reduction reaction(ORR)is imperative in application.Herein,a catalyst based on FeCo-N encapsuled in nitrogen-doped carbon nanotubes has been prepared,which provides an implementable method to design controlled structures with excellent bifunction al electrocatalytic activities.By adjusting the molar ratio of two metals,the synthesized FeCo-N-C catalyst delivers a competitive ORR and OER performance compared with commercial Pt/C and IrO_(2),performing a low overvoltage gap between ORR(E_(1/2))and OER(E_(j=10))of 0.8 V.Moreover,as a promising cathode in zinc air battery,the FeCo-N-C catalyst possesses an affirmative stability of over 100 h and large power density(129 mW·cm^(-2)).This work demonstrates that FeCo-N-C is one of the most promising catalysts for zinc air batteries and provides a possibility for exploration of batteries with high stability by adjusting the molar ratio of metals in the catalysts.
基金the Fundamental Research Funds for the Central Universities(No.30920021120)the Key Laboratory of Biomass Energy and Material,Jiangsu Province(No.JSBEM201912)+1 种基金the National Natural Science Foundation of China(No.21905089)the Chinese Postdoctoral Science Foundation(No.2019M662775)for financial support。
文摘A facile,gram-scale and sustainable approach has been established for the synthesis of single-atomic-site iron on N-doped carbon(Fe_(SA)@NC-20A)via the pyrolysis of aniline modified FeZn-ZIFs,in which the synthesis of zeolitic imidazolate frameworks(ZIFs)can be accomplished in water at room temperature,and no acid etching is required.The as-synthesized catalyst exhibits better performance on the chemoselective hydrogenation of nitroarenes with a broad substrate scope(turnover frequency(TOF)up to 1,727 h^(-1),23 examples)than most of previously reported works.Based on high-angle annular dark field scanning transmission microscopy(HAADF-STEM)images in combination with X-ray photoelectron spectroscopy(XPS),X-ray absorption spectroscopy(XAS),electron spin resonance(ESR),and Mossbauer spectroscopy,Fe is dispersed as single atoms via forming FeNx(x=4-6).This work not only determines the active sites of FesA@NC-20A for hydrogenation(FeN4),but also proposes tentative pathways for both N-H activation of hydrazine and the reduction of nitroarene on FeN4 site,both of which are the key steps for the hydrogenation of nitroarenes.In addition,this catalyst shows excellent stability,and no significant activity degradation is observed when recycling for 10 times or restoring in air for 2 months.
基金supported by the Natural Science Foundation of China(Nos.22125902,U2032202,21975243 and 21825302)the National Program for Support of Topnotch Young Professionals,the Fundamental Research Funds for the Central Universities(No.WK2030020032)+1 种基金the DNL cooperation Fund,CAS(No.DNL202020)the Anhui Science Fund for Distinguished Young Scholars(No.2208085J15).
文摘The undesirable shuttle effect and sluggish redox kinetics of polysulfides seriously result in low sulfur utilization and poor capacity retention.Here,an integrated strategy is proposed by rational designing multifunctional architecture to manipulate the redox kinetics of polysulfides,specifically,by employing iron atoms(Fe-As)and iron-species nanoparticles(Fe-NPs)co-embedded nitrogen-doped carbon nanotube(Fe-NCNT)as catalyst and host for sulfur.The synergistic cooperation of Fe-As and Fe-NPs provides efficient active sites to facilitate the diffusion,strengthen the affinities,and promote the conversion reactions for polysulfides.Furthermore,the NCNT not only offers practical Li+transport pathways but also immobilize the polysulfides effectively.Benefiting from these merits,the Fe-NCNT/S electrodes exhibit high initial specific capacity of 1502.6 mAh/g at 0.1 C,outstanding rate performance(830 mAh/g at 2 C),and good cycling performance(597.8 mAh/g after 500 cycles with an ultralow capacity fading rate of 0.069%per cycle).This work features the distinct interaction of iron atom-nanoparticles on facilitating immobilization-diffusion-transformation process of polysulfides,and it also expected to pave the way for the application in practical Li-S batteries.
基金supported by the National Natural Science Foundation of China (Nos. 21777194 and 21507168)
文摘Ibuprofen(IBU),a nonsteroidal anti-inflammatory drug,is becoming an important member of pharmaceuticals and personal care products(PPCPs)as emerging pollutants.To degrade IBU,magnetic Fe_3C nanoparticles embedded on N-doped carbon(Fe_3C/NC)were prepared as a catalyst by a sol–gel combustion method.As characterized,the Fe_3C/NC nanoparticles were composed of a NC nano-sheet and capsulated Fe_3C particles on the sheet.The Fe_3C/NC nanoparticles were confirmed an efficient catalyst for peroxymonosulfate(PMS)activation to generate sulfate radicals(SO_4^(·-)),single oxygen(~1O_2)and hydroxyl radicals(·OH)toward the degradation of IBU.The added IBU(10 mg/L)was almost completely removed in 30 min by using 0.1 g/L Fe_3C/NC and 2 g/L PMS.The catalyst was confirmed to have good ability and excellent reusability through leaching measurements and cycle experiments.A catalytic mechanism was proposed for the catalytic activation of PMS on Fe_3C/NC,which involves both Fe_3C reactive sites and N-doped carbon matrix as reactive sites in Fe_3C/NC.Moreover,the degradation pathway of IBU in the Fe_3C/NC-PMS system was proposed according to the detections of degradation intermediates.