Research on metal-organic framework(MOF)-based non-enzymatic glucose sensors usually ignores the impact of the surface reconstruction degree of MOF on the activity of catalyzing glucose oxidation.In this work,we choos...Research on metal-organic framework(MOF)-based non-enzymatic glucose sensors usually ignores the impact of the surface reconstruction degree of MOF on the activity of catalyzing glucose oxidation.In this work,we choose zeolitic imidazolate framework-67(ZIF-67),which is commonly used in glucose sensing,as a representative to investigate the influence of reconstruction degree on its structure and glucose catalytic performance.By employing the electrochemical activation strategy,the activity of ZIF-67 in catalyzing glucose gradually increased with the prolongation of the activation time,reaching the optimum after 2 h activation.The detection sensitivity of the activated ZIF-67 was 19 times higher than that of the initial ZIF-67,and the limit of detection(LOD)was lowered from 7 to 0.4μM.Our findings demonstrate that the oxidation degree of ZIF-67 deepened rapidly with continuously activation and was basically reconstructed to CoOOH after 2 h activation,accompanied by a morphological change from cuboctahedral to flower-like.Simultaneously,theoretical investigation revealed that ZIF-67 is not suitable as a stable glucose sensor electrode since the adsorbed glucose molecules hasten the dissociation of ligands and the breaking of Co-N bond in ZIF-67.Therefore,our work has important implications for the rational design of next-generation MOF-based glucose sensors.展开更多
Transition metal oxides with layered structure have been widely used as cathode materials for lithium-ion batteries(LIBs)which have relatively high energy density,large capacity and long life.However,in the long-term ...Transition metal oxides with layered structure have been widely used as cathode materials for lithium-ion batteries(LIBs)which have relatively high energy density,large capacity and long life.However,in the long-term electrochemical cycle,the inevitable degradation of performance of LIBs due to structural degradation in cathodes severely restricts their large-scale practical applications.Understanding the underlying mechanism of structural degradation is the most critical scientific problem.Recently,in situ transmission electron microscopy(TEM)has become a useful tool to study the structural and compositional evolutions at atomic scale in electrochemical reactions,which provided a unique and in-depth understanding of the structural degradation.In this review,we discuss the recent advances in the in situ TEM,focusing on its role in revealing the structural degradation mechanisms in the four key places:(1)the interface between the cathodes and electrolyte;(2)the cathode surface;(3)the particle interior and(4)those induced by thermal effect.The insight gained by the in-situ TEM which is still developing at its fast pace is unique and expected to provide guidance for designing better layered cathode materials.展开更多
As the main limiting step of overall water splitting,oxygen evolution reaction(OER)is urgent to be enhanced by developing efficient catalysts to promote the process of electrolytic water.Based on theoretical analysis,...As the main limiting step of overall water splitting,oxygen evolution reaction(OER)is urgent to be enhanced by developing efficient catalysts to promote the process of electrolytic water.Based on theoretical analysis,the Ni-metal-organic framework(Ni-MOF)and NiFe-layered double hydroxide(NiFe-LDH)(NiFe-LDH/MOF)heterostructure can optimize the energy barrier of the OER process and decrease the adsorption energy of oxygen-containing intermediates,effectively accelerating the OER kinetics.Accordingly,layered NiFe-LDH/MOF heterostructures are in situ constructed through a facile two-step reaction process,with substantial oxygen defects and lattice defects that further improve the catalytic performance.As a result,only 208 and 275 mV OER overpotentials are needed for NiFe-LDH/MOF to drive the current densities of 20 and 100 mA·cm^(-2)in 1 M KOH solutions,and even maintain catalytic stability of 100 h at 20 mA·cm^(-2).When applied to seawater oxidation,only 235 and 307 mV OER overpotentials are required to achieve the current densities of 20 and 100 mA·cm^(-2),respectively,with almost no attenuation for 100 h stability test at 20 mA·cm^(-2),all better than commercial RuO_(2).This work provides the theoretical and experimental basis and a new idea for efficiently driving fresh water and seawater cracking by heterostructure and defect coupling design toward catalysts.展开更多
Iron-based oxygen reduction reaction(ORR)catalysts have been the focus of research,and iron sources play an important role for the preparation of efficient ORR catalysts.Here,we successfully use LiFePO4 as ideal sourc...Iron-based oxygen reduction reaction(ORR)catalysts have been the focus of research,and iron sources play an important role for the preparation of efficient ORR catalysts.Here,we successfully use LiFePO4 as ideal sources of Fe and P to construct the heteroatom doped Fe-based carbon materials.The obtained Fe-N-P co-doped coral-like carbon nanotube arrays encapsulated Fe2P catalyst(C-ZIF/LFP)shows very high half-wave potential of 0.88 V in alkaline electrolytes toward ORR,superior to Pt/C(0.85 V),and also presents a high half-wave potential of 0.74 V in acidic electrolytes,comparable to Pt/C(0.8 V).When further applied into a home-made Zn-air battery as cathode,a peak power density of 140 mW·cm^-2 is reached,exceeds commercial Pt/C(110 mW·cm^-2).Besides,it also presents exceptional durability and methanol resistance compared with Pt/C.Noticeably,the preparation method of such a high-performance catalyst is simple and easy to optimize,suitable for the large-scale production.What’s more,it opens up a more sustainable development scenario to reduce the hazardous wastes such as LiFePO4 by directly using them for preparing high-performance ORR catalysts.展开更多
基金the National Natural Science Foundation of China(Nos.22102128 and 22279097)the Fundamental Research Funds for the Central Universities(No.WUT:2022IVA168).
文摘Research on metal-organic framework(MOF)-based non-enzymatic glucose sensors usually ignores the impact of the surface reconstruction degree of MOF on the activity of catalyzing glucose oxidation.In this work,we choose zeolitic imidazolate framework-67(ZIF-67),which is commonly used in glucose sensing,as a representative to investigate the influence of reconstruction degree on its structure and glucose catalytic performance.By employing the electrochemical activation strategy,the activity of ZIF-67 in catalyzing glucose gradually increased with the prolongation of the activation time,reaching the optimum after 2 h activation.The detection sensitivity of the activated ZIF-67 was 19 times higher than that of the initial ZIF-67,and the limit of detection(LOD)was lowered from 7 to 0.4μM.Our findings demonstrate that the oxidation degree of ZIF-67 deepened rapidly with continuously activation and was basically reconstructed to CoOOH after 2 h activation,accompanied by a morphological change from cuboctahedral to flower-like.Simultaneously,theoretical investigation revealed that ZIF-67 is not suitable as a stable glucose sensor electrode since the adsorbed glucose molecules hasten the dissociation of ligands and the breaking of Co-N bond in ZIF-67.Therefore,our work has important implications for the rational design of next-generation MOF-based glucose sensors.
基金financially supported by the National Natural Science Foundation of China(Nos.52127816,520722825 and 2022072)the Hubei Provincial Natural Science Foundation of China(Distinguished Young Scholars,No.2022CFA042)the In-dependent Innovation Projects of the Hubei Longzhong Laboratory(No.2022ZZ-10).
文摘Transition metal oxides with layered structure have been widely used as cathode materials for lithium-ion batteries(LIBs)which have relatively high energy density,large capacity and long life.However,in the long-term electrochemical cycle,the inevitable degradation of performance of LIBs due to structural degradation in cathodes severely restricts their large-scale practical applications.Understanding the underlying mechanism of structural degradation is the most critical scientific problem.Recently,in situ transmission electron microscopy(TEM)has become a useful tool to study the structural and compositional evolutions at atomic scale in electrochemical reactions,which provided a unique and in-depth understanding of the structural degradation.In this review,we discuss the recent advances in the in situ TEM,focusing on its role in revealing the structural degradation mechanisms in the four key places:(1)the interface between the cathodes and electrolyte;(2)the cathode surface;(3)the particle interior and(4)those induced by thermal effect.The insight gained by the in-situ TEM which is still developing at its fast pace is unique and expected to provide guidance for designing better layered cathode materials.
基金This work was supported by the National Natural Science Foundation of China(No.22075223)the State Key Laboratory of Advanced Technology for Materials Synthesis and Processing(Wuhan University of Technology)(No.2022-ZD-4).
文摘As the main limiting step of overall water splitting,oxygen evolution reaction(OER)is urgent to be enhanced by developing efficient catalysts to promote the process of electrolytic water.Based on theoretical analysis,the Ni-metal-organic framework(Ni-MOF)and NiFe-layered double hydroxide(NiFe-LDH)(NiFe-LDH/MOF)heterostructure can optimize the energy barrier of the OER process and decrease the adsorption energy of oxygen-containing intermediates,effectively accelerating the OER kinetics.Accordingly,layered NiFe-LDH/MOF heterostructures are in situ constructed through a facile two-step reaction process,with substantial oxygen defects and lattice defects that further improve the catalytic performance.As a result,only 208 and 275 mV OER overpotentials are needed for NiFe-LDH/MOF to drive the current densities of 20 and 100 mA·cm^(-2)in 1 M KOH solutions,and even maintain catalytic stability of 100 h at 20 mA·cm^(-2).When applied to seawater oxidation,only 235 and 307 mV OER overpotentials are required to achieve the current densities of 20 and 100 mA·cm^(-2),respectively,with almost no attenuation for 100 h stability test at 20 mA·cm^(-2),all better than commercial RuO_(2).This work provides the theoretical and experimental basis and a new idea for efficiently driving fresh water and seawater cracking by heterostructure and defect coupling design toward catalysts.
基金This work was financially supported by the National Key Research and Development Program of China(No.2016YFA0202603)the National Natural Science Foundation of China(No.51672204).
文摘Iron-based oxygen reduction reaction(ORR)catalysts have been the focus of research,and iron sources play an important role for the preparation of efficient ORR catalysts.Here,we successfully use LiFePO4 as ideal sources of Fe and P to construct the heteroatom doped Fe-based carbon materials.The obtained Fe-N-P co-doped coral-like carbon nanotube arrays encapsulated Fe2P catalyst(C-ZIF/LFP)shows very high half-wave potential of 0.88 V in alkaline electrolytes toward ORR,superior to Pt/C(0.85 V),and also presents a high half-wave potential of 0.74 V in acidic electrolytes,comparable to Pt/C(0.8 V).When further applied into a home-made Zn-air battery as cathode,a peak power density of 140 mW·cm^-2 is reached,exceeds commercial Pt/C(110 mW·cm^-2).Besides,it also presents exceptional durability and methanol resistance compared with Pt/C.Noticeably,the preparation method of such a high-performance catalyst is simple and easy to optimize,suitable for the large-scale production.What’s more,it opens up a more sustainable development scenario to reduce the hazardous wastes such as LiFePO4 by directly using them for preparing high-performance ORR catalysts.
