Zero or negative emissions of carbon dioxide(CO2)is the need of the times,as inexorable rising and alarming levels of CO2 in the atmosphere lead to global warming and severe climate change.The electrochemical CO2 redu...Zero or negative emissions of carbon dioxide(CO2)is the need of the times,as inexorable rising and alarming levels of CO2 in the atmosphere lead to global warming and severe climate change.The electrochemical CO2 reduction(eCO2R)to value‐added fuels and chemicals by using renewable electricity provides a cleaner and more sustainable route with economic benefits,in which the key is to develop clean and economical electrocatalysts.Carbon‐based catalyst materials possess desirable properties such as high offset potential for H2 evolution and chemical stability at the negative applied potential.Although it is still challenging to achieve highly efficient carbon‐based catalysts,considerable efforts have been devoted to overcoming the low selectivity,activity,and stability.Here,we summarize and discuss the recent progress in carbon‐based metal‐free catalysts including carbon nanotubes,carbon nanofibers,carbon nanoribbons,graphene,carbon nitride,and diamonds with an emphasis on their activity,product selectivity,and stability.In addition,the key challenges and future potential approaches for efficient eCO2R to low carbon‐based fuels are highlighted.For a good understanding of the whole history of the development of eCO2R,the CO2 reduction reactions,principles,and techniques including the role of electrolytes,electrochemical cell design and evaluation,product selectivity,and structural composition are also discussed.The metal/metal oxides decorated with carbon‐based electrocatalysts are also summarized.We aim to provide insights for further development of carbon‐based metal‐free electrocatalysts for CO2 reduction from the perspective of both fundamental understanding and technological applications in the future.展开更多
Rapid capacity decay and sluggish reaction kinetics are major barriers hindering the applications of manganese-based cathode materials for aqueous zinc-ion batteries.Herein,the effects of crystal plane on the in-situ ...Rapid capacity decay and sluggish reaction kinetics are major barriers hindering the applications of manganese-based cathode materials for aqueous zinc-ion batteries.Herein,the effects of crystal plane on the in-situ transformation behavior and electrochemical performance of manganese-based cathode is discussed.A comprehensive discussion manifests that the exposed(100)crystal plane is beneficial to the phase transformation from tunnel-structured MnO_(2) to layer-structured ZnMn_(3)O_(7)·3H_(2)O,which plays a critical role for the high reactivity,high capacity,fast diffusion kinetics and long cycling stability.Additionally,a two-stage zinc storage mechanism can be demonstrated,involving continuous activation reaction and phase transition reaction.As expected,it exhibits a high capacity of 275 mAh g^(-1)at 100 mA g^(-1),a superior durability over 1000 cycles and good rate capability.This study may open new windows toward developing advanced cathodes for ZIBs,and facilitate the applications of ZIBs in large-scale energy storage system.展开更多
In the pursuit of multifunctional coatings,the controlled growth of materials on stationary platforms holds paramount importance for achieving superior corrosion protection and optimal photocatalytic performance.This ...In the pursuit of multifunctional coatings,the controlled growth of materials on stationary platforms holds paramount importance for achieving superior corrosion protection and optimal photocatalytic performance.This study introduces a cutting-edge approach,intertwining bifunctional metal-organic frameworks(MOFs)seamlessly into defective MgO layers produced by the anodic oxidation of AZ31 alloy.Key metallic oxides of Zn,Sn,and V take center stage as metallic sources for MOF formation,complemented by the organic prowess of L-Tryptophan as anα-amino acid linker.Leveraging the electronic structure of metallic oxides reacting with tryptophan molecules,controlled morphologies with distinct characteristics are induced on the defective surface of the MgO layer,enabling the precise modulation of surface defects.The hybrid composite demonstrates an adaptive microstructure in diverse aqueous environments,offering dual functionality with electrochemical stability and visible light photocatalytic activity for crystal violet degradation.Among the samples,the SnOF complex exhibited remarkable electrochemical stability with a low corrosion current density of 7.50×10^(−10)A·cm^(−2),along with a 94.56%degradation efficiency after 90 min under visible light exposure.The VOF complex,under similar visible light conditions,demonstrated exceptional performance with a higher degradation efficiency of 97.79%and excellent electrochemical stability characterized by a corrosion current density of 3.26×10^(−9)A·cm^(−2).Additionally,Density Functional Theory(DFT)computations shed light on the basic bonding patterns between MOFs and inorganic components,providing electronic understanding of their electrochemical and photocatalytic activities.展开更多
采用KOH活化石墨烯,通过固相法制备了磷酸铁锂/碱活化石墨烯(LFP/CA-G)复合材料,通过SEM、Raman、XRD和电化学测试对复合材料的结构和性能进行表征,结果表明:通过固相法制备的LFP/CA-G复合材料稳定性较好,在1C倍率下循环50次的容量保持...采用KOH活化石墨烯,通过固相法制备了磷酸铁锂/碱活化石墨烯(LFP/CA-G)复合材料,通过SEM、Raman、XRD和电化学测试对复合材料的结构和性能进行表征,结果表明:通过固相法制备的LFP/CA-G复合材料稳定性较好,在1C倍率下循环50次的容量保持率为100%;LFP/CA-G复合材料的0.2C首次放电比容量为158.8m Ah/g,较磷酸铁锂/石墨烯(LFP/G)提高了3.1 m Ah/g;其3C倍率的放电比容量为139 m Ah/g,较LFP/G提高了7 m Ah/g。LFP/CA-G复合材料具有更好的可逆性,其阻抗更小。这是因为碱活化的石墨烯具有丰富的微孔,有利于缩短锂离子的迁移路径,减小了极化。展开更多
基金The authors thank the financial support from the“Scientific and Technical Innovation Action Plan”Basic Research Field of the Shanghai Science and Technology Committee(19JC1410500)the Fundamental ResearchFunds for the Central Universities(2232018A3‐06)the National Natural Science Foundation of China(91645110).
文摘Zero or negative emissions of carbon dioxide(CO2)is the need of the times,as inexorable rising and alarming levels of CO2 in the atmosphere lead to global warming and severe climate change.The electrochemical CO2 reduction(eCO2R)to value‐added fuels and chemicals by using renewable electricity provides a cleaner and more sustainable route with economic benefits,in which the key is to develop clean and economical electrocatalysts.Carbon‐based catalyst materials possess desirable properties such as high offset potential for H2 evolution and chemical stability at the negative applied potential.Although it is still challenging to achieve highly efficient carbon‐based catalysts,considerable efforts have been devoted to overcoming the low selectivity,activity,and stability.Here,we summarize and discuss the recent progress in carbon‐based metal‐free catalysts including carbon nanotubes,carbon nanofibers,carbon nanoribbons,graphene,carbon nitride,and diamonds with an emphasis on their activity,product selectivity,and stability.In addition,the key challenges and future potential approaches for efficient eCO2R to low carbon‐based fuels are highlighted.For a good understanding of the whole history of the development of eCO2R,the CO2 reduction reactions,principles,and techniques including the role of electrolytes,electrochemical cell design and evaluation,product selectivity,and structural composition are also discussed.The metal/metal oxides decorated with carbon‐based electrocatalysts are also summarized.We aim to provide insights for further development of carbon‐based metal‐free electrocatalysts for CO2 reduction from the perspective of both fundamental understanding and technological applications in the future.
基金This work was supported by the National Natural Science Foundation of China(Grant Nos.51932011 and 52072411)Science and technology innovation Program of Hunan Province(Grant no.2021RC3001)Natural Science Foundation of Hunan Province(Grant no.2021JJ20060,2018RS3019 and 2019JJ30033).
文摘Rapid capacity decay and sluggish reaction kinetics are major barriers hindering the applications of manganese-based cathode materials for aqueous zinc-ion batteries.Herein,the effects of crystal plane on the in-situ transformation behavior and electrochemical performance of manganese-based cathode is discussed.A comprehensive discussion manifests that the exposed(100)crystal plane is beneficial to the phase transformation from tunnel-structured MnO_(2) to layer-structured ZnMn_(3)O_(7)·3H_(2)O,which plays a critical role for the high reactivity,high capacity,fast diffusion kinetics and long cycling stability.Additionally,a two-stage zinc storage mechanism can be demonstrated,involving continuous activation reaction and phase transition reaction.As expected,it exhibits a high capacity of 275 mAh g^(-1)at 100 mA g^(-1),a superior durability over 1000 cycles and good rate capability.This study may open new windows toward developing advanced cathodes for ZIBs,and facilitate the applications of ZIBs in large-scale energy storage system.
基金supported by the National Research Foundation of Korea(NRF)funded by the Korean government(MSIT)(No.2022R1A2C1006743).
文摘In the pursuit of multifunctional coatings,the controlled growth of materials on stationary platforms holds paramount importance for achieving superior corrosion protection and optimal photocatalytic performance.This study introduces a cutting-edge approach,intertwining bifunctional metal-organic frameworks(MOFs)seamlessly into defective MgO layers produced by the anodic oxidation of AZ31 alloy.Key metallic oxides of Zn,Sn,and V take center stage as metallic sources for MOF formation,complemented by the organic prowess of L-Tryptophan as anα-amino acid linker.Leveraging the electronic structure of metallic oxides reacting with tryptophan molecules,controlled morphologies with distinct characteristics are induced on the defective surface of the MgO layer,enabling the precise modulation of surface defects.The hybrid composite demonstrates an adaptive microstructure in diverse aqueous environments,offering dual functionality with electrochemical stability and visible light photocatalytic activity for crystal violet degradation.Among the samples,the SnOF complex exhibited remarkable electrochemical stability with a low corrosion current density of 7.50×10^(−10)A·cm^(−2),along with a 94.56%degradation efficiency after 90 min under visible light exposure.The VOF complex,under similar visible light conditions,demonstrated exceptional performance with a higher degradation efficiency of 97.79%and excellent electrochemical stability characterized by a corrosion current density of 3.26×10^(−9)A·cm^(−2).Additionally,Density Functional Theory(DFT)computations shed light on the basic bonding patterns between MOFs and inorganic components,providing electronic understanding of their electrochemical and photocatalytic activities.
文摘采用KOH活化石墨烯,通过固相法制备了磷酸铁锂/碱活化石墨烯(LFP/CA-G)复合材料,通过SEM、Raman、XRD和电化学测试对复合材料的结构和性能进行表征,结果表明:通过固相法制备的LFP/CA-G复合材料稳定性较好,在1C倍率下循环50次的容量保持率为100%;LFP/CA-G复合材料的0.2C首次放电比容量为158.8m Ah/g,较磷酸铁锂/石墨烯(LFP/G)提高了3.1 m Ah/g;其3C倍率的放电比容量为139 m Ah/g,较LFP/G提高了7 m Ah/g。LFP/CA-G复合材料具有更好的可逆性,其阻抗更小。这是因为碱活化的石墨烯具有丰富的微孔,有利于缩短锂离子的迁移路径,减小了极化。
