The past decade has witnessed a rapid surge of interest in the research and development of non-precious metal-based electrocatalysts for the oxygen reduction reaction （ORR）. Until now, the best catalysts in acidic e...The past decade has witnessed a rapid surge of interest in the research and development of non-precious metal-based electrocatalysts for the oxygen reduction reaction （ORR）. Until now, the best catalysts in acidic electrolytes have exclusively been Fe-N-C-type materials from high-temperature pyrolysis. Despite the ORR activities of metal phthalocyanine or porphyrin macrocydes having long been known, their durability remains poor. In this work, we use these macrocycles as a basis to develop a novel organic-carbon hybrid material from in-situ polymerization of iron phthalocyanine on conductive multiwalled carbon nanotube scaffolds using a low-temperature microwave heating method. At an optimal polymer- to-carbon ratio, the hybrid electrocatalyst exhibits excellent ORR activity with a positive half-wave potential （0.80 V）, large mass activity （up to 18.0 A/g at 0.80 V）, and a low peroxide yield （〈3%）. In addition, strong electronic coupling between the polymer and carbon nanotubes is believed to suppress demetallization of the macrocycles, significantly improving cycling stability in acids. Our study represents a rare example of non-precious metal-based electrocatalysts prepared without high-temperature pyrolysis, while having ORR activity in acidic media with potential for practical applications.展开更多
Development of high-efficiency electrode materials for the electrochemical CO_(2)reduction reaction(CO_(2)RR)with high current density and selectivity compatible with industry is an important but significant challenge...Development of high-efficiency electrode materials for the electrochemical CO_(2)reduction reaction(CO_(2)RR)with high current density and selectivity compatible with industry is an important but significant challenge.Herein,we describe a facile strategy to enhance the selectivity and current density by regulating the local electron density of the cobalt site in a series of stable,conjugated,bimetallic Co/Zn polyphthalocyanine frameworks Co_(x)Zn_(y)PPc with an AB stacking model under alkaline aqueous conditions.When adjusting the ratio of Co and Zn to 3:1,the optimal Co3Zn1PPc exhibits an industry-compatible CO partial current density of 212 mA cm^(−2)at−0.9 V versus reversible hydrogen electrode in a flow cell,which is 1.7 and 9.1 times that of the single metal polyphthalocyanine CoPPc and ZnPPc,respectively.Co_(3)Zn_(1)PPc shows a high CO Faraday efficiency of more than 90%in a wide operating potential window of−0.3 to−0.9 V.In-depth experimental and theoretical analysis revealed that introduction of electron-rich Zn atoms modified the electron density of the active Co center,placing Co in the electronrich region and weakening the bonding strength with the reaction intermediate,thereby improving the CO_(2)RR performance.These results clarify the interaction mechanism of dual metal sites at the atomic level and provide a new avenue for the design of electrocatalysts with potential in industrial applications.展开更多
Recently,Li-CO_(2) battery has gradually become a research hotspot due to its high discharge capacity,energy density and environmental benefits.However,it has been an important problem for researchers because of its s...Recently,Li-CO_(2) battery has gradually become a research hotspot due to its high discharge capacity,energy density and environmental benefits.However,it has been an important problem for researchers because of its slow decomposition kinetics and difficult to generalize to practical application.Herein,we prepared copper polyphthalocyanine-carbon nanotubes composites(CuPPc-CNTs)by solvothermal in-situ polymerization of copper phthalocyanine on the surface of carbon nanotubes as cathode for reversible Li-CO_(2) batteries,which exhibits a high discharge capacity of 18,652.7 mAh·g^(-1) at current density of 100 mA·g^(-1),1.64 V polarization at 1,000 mA·g^(-1),and a stable cycles number of 160 is close to 1,630 h of charge-discharge process at 200 mA·g^(-1).Copper polyphthalocyanine has highly efficient copper single-atom catalytic sites with excellent CO_(2) adsorption and activation,while carbon nanotubes provide a conductive network.The synergistic effect of the two compounds enables it to have excellent catalytic activity.The density functional theory(DFT)calculation proved that the addition of copper polyphthalocyanine significantly improved the CO_(2) adsorption and activation process.This study provides an opportunity for the research of covalent organic polymers(COPs)single-atom catalyst in Li-CO_(2) battery field.展开更多
The oxygen reduction reaction (ORR) is the cornerstone reaction of the cathode in metal±air batteries;however,slow kinetics requires high-performance catalysts to promote the reaction.Polyphthalocyanine (PPc) has...The oxygen reduction reaction (ORR) is the cornerstone reaction of the cathode in metal±air batteries;however,slow kinetics requires high-performance catalysts to promote the reaction.Polyphthalocyanine (PPc) has a typical chemical cross-linking structure and uniformly dispersed metal active sites,but its poor activity and conductivity limit its applications as an ORR catalyst.Herein,a manageable and convenient strategy is proposed to synthesize ternary ORR catalysts through the low-temperature pyrolysis of Fe PPc.The optimal catalyst,Fe_(3)O_(4)/Fe_(3)N/Fe-N-C@PC-2.5,exhibits excellent ORR activity in alkaline solution with a half-wave potential of 0.90 V,which is significantly higher than that of commercial 20%Pt/C (0.84 V).Electrochemical tests and extended X-ray absorption fine structure spectroscopy reveal that the superior ORR activity of Fe_(3)O_(4)/Fe_(3)N/Fe-N-C@PC-2.5 could be ascribed to the balance of its ternary components(i.e.,Fe_(3)O_(4),Fe_(3)N,and Fe-N;species).A Zn±air battery incorporating Fe_(3)O_(4)/Fe_(3)N/Fe-N-C@PC-2.5 as an air cathodic catalyst delivers a high open-circuit voltage and peak power density.During galvanostatic discharge,the battery demonstrates a specific capacity of 815.7 mA h g^(-1).The facile strategy of using PPc to develop high-performance composite electrocatalysts may be expanded to develop new types of catalysts in the energy field.展开更多
Lithium-sulfur(Li-S)batteries have been considered as the next generation high energy storage devices.However,its commercialization has been hindered by several issues,especially the dissolution and shuttle of the sol...Lithium-sulfur(Li-S)batteries have been considered as the next generation high energy storage devices.However,its commercialization has been hindered by several issues,especially the dissolution and shuttle of the soluble lithium polysulfides(LiPSs)as well as the slow reaction kinetics of LiPSs which may make shuttling effect even worse.Herein,we report a strategy to address this issue by in-situ transformation of Co−N_(x) coordinations in cobalt polyphthalocyanine(CoPPc)into Co nanoparticles(Co NPs)embedded in carbon matrix and mono-dispersed on graphene flakes.The Co NPs can provide rich binding and catalytic sites,while graphene flakes act as ideally LiPSs transportation and electron conducting platform.With a remarkable enhanced reaction kinetics of LiPSs via these merits,the sulfur host with a sulfur content up to 70 wt%shows a high initial capacity of 1048 mA∙h/g at 0.2C,good rate capability up to 399 mA·h/g at 2C.展开更多
Exploring non-noble metal and high-activity electrocatalysts through a simple and controllable protocol remains a great challenge for oxygen reduction reaction(ORR)and zinc-air batteries.Herein,we developed a melt pol...Exploring non-noble metal and high-activity electrocatalysts through a simple and controllable protocol remains a great challenge for oxygen reduction reaction(ORR)and zinc-air batteries.Herein,we developed a melt polymerization strategy to synthesize iron-polyphthalocyanine(FePPc)metallic-organic frameworks(MOFs)over the carbon black matrix(Fe PPc@CB).Through noncovalentπ-πinteractions,Fe PPc molecules can anchor on carbon matrix,thus facilitating the electron transfer process and stabilizing the systems.Owing to abundant free electrons and atomically MN4 catalytic sites in the macrocycle structure,FePPc@CB exhibits excellent oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)electrocatalytic activity.The FePPc@CB also delivers excellent performances for liquid and flexible all-solidstate batteries compared to that of commercial Pt/C,making it a promising ORR/OER electrocatalyst.展开更多
基金Acknowledgements We acknowledge supports from the National Natural Science Foundation of China （Nos. 51472173, 51522208 and 21472135）, the Natural Science Foundation of Jiangsu Province （Nos. BK20140302 and SBK2015010320）, the Priority Academic Program Development of Jiangsu Higher Education Institutions and Collaborative Innovation Center of Suzhou Nano Science and Technology
文摘The past decade has witnessed a rapid surge of interest in the research and development of non-precious metal-based electrocatalysts for the oxygen reduction reaction （ORR）. Until now, the best catalysts in acidic electrolytes have exclusively been Fe-N-C-type materials from high-temperature pyrolysis. Despite the ORR activities of metal phthalocyanine or porphyrin macrocydes having long been known, their durability remains poor. In this work, we use these macrocycles as a basis to develop a novel organic-carbon hybrid material from in-situ polymerization of iron phthalocyanine on conductive multiwalled carbon nanotube scaffolds using a low-temperature microwave heating method. At an optimal polymer- to-carbon ratio, the hybrid electrocatalyst exhibits excellent ORR activity with a positive half-wave potential （0.80 V）, large mass activity （up to 18.0 A/g at 0.80 V）, and a low peroxide yield （〈3%）. In addition, strong electronic coupling between the polymer and carbon nanotubes is believed to suppress demetallization of the macrocycles, significantly improving cycling stability in acids. Our study represents a rare example of non-precious metal-based electrocatalysts prepared without high-temperature pyrolysis, while having ORR activity in acidic media with potential for practical applications.
基金support from the National Key Research and Development Program of China(nos.2018YFA0208600,2018YFA0704502)NSFC(nos.21871263,22071245,and 22033008)Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China(no.2021ZZ103).
文摘Development of high-efficiency electrode materials for the electrochemical CO_(2)reduction reaction(CO_(2)RR)with high current density and selectivity compatible with industry is an important but significant challenge.Herein,we describe a facile strategy to enhance the selectivity and current density by regulating the local electron density of the cobalt site in a series of stable,conjugated,bimetallic Co/Zn polyphthalocyanine frameworks Co_(x)Zn_(y)PPc with an AB stacking model under alkaline aqueous conditions.When adjusting the ratio of Co and Zn to 3:1,the optimal Co3Zn1PPc exhibits an industry-compatible CO partial current density of 212 mA cm^(−2)at−0.9 V versus reversible hydrogen electrode in a flow cell,which is 1.7 and 9.1 times that of the single metal polyphthalocyanine CoPPc and ZnPPc,respectively.Co_(3)Zn_(1)PPc shows a high CO Faraday efficiency of more than 90%in a wide operating potential window of−0.3 to−0.9 V.In-depth experimental and theoretical analysis revealed that introduction of electron-rich Zn atoms modified the electron density of the active Co center,placing Co in the electronrich region and weakening the bonding strength with the reaction intermediate,thereby improving the CO_(2)RR performance.These results clarify the interaction mechanism of dual metal sites at the atomic level and provide a new avenue for the design of electrocatalysts with potential in industrial applications.
基金supported by the National Natural Science Foundation of China (11247281)Beijing Natural Science Foundation, China (2120001)Excellent Youth Fund of Hebei Province Department of Education, China (Y2012010)~~
基金The authors acknowledge the financial support for this work from the Natural Science Foundation of Jiangsu Province(Nos.BK20190413 and BK20210616)the National Defense Technology Innovation Special Zone Spark Project(No.2016300TS00911901)+3 种基金the China Postdoctoral Science Foundation(No.2019M661825)the Jiangsu Key Laboratory of Electrochemical Energy-Storage Technologies(EEST2021-2)the Funding of Research and Practice Innovation Program in NUAA for Graduate Education(No.xcxjh20210605)a Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD).
文摘Recently,Li-CO_(2) battery has gradually become a research hotspot due to its high discharge capacity,energy density and environmental benefits.However,it has been an important problem for researchers because of its slow decomposition kinetics and difficult to generalize to practical application.Herein,we prepared copper polyphthalocyanine-carbon nanotubes composites(CuPPc-CNTs)by solvothermal in-situ polymerization of copper phthalocyanine on the surface of carbon nanotubes as cathode for reversible Li-CO_(2) batteries,which exhibits a high discharge capacity of 18,652.7 mAh·g^(-1) at current density of 100 mA·g^(-1),1.64 V polarization at 1,000 mA·g^(-1),and a stable cycles number of 160 is close to 1,630 h of charge-discharge process at 200 mA·g^(-1).Copper polyphthalocyanine has highly efficient copper single-atom catalytic sites with excellent CO_(2) adsorption and activation,while carbon nanotubes provide a conductive network.The synergistic effect of the two compounds enables it to have excellent catalytic activity.The density functional theory(DFT)calculation proved that the addition of copper polyphthalocyanine significantly improved the CO_(2) adsorption and activation process.This study provides an opportunity for the research of covalent organic polymers(COPs)single-atom catalyst in Li-CO_(2) battery field.
基金financially supported by the Basic Research Project of the Science and Technology Innovation Commission of Shenzhen (JCYJ20200109141640095 and JCYJ20190809115413414)the National Natural Science Foundation of China (21671096 and 21905180)+2 种基金the Natural Science Foundation of Guangdong Province (2018A030310225)Guangdong Provincial Key Laboratory of Energy Materials for Electric Power (2018B030322001)support from the Center for Computational Science and Engineering and Core Research Facilities of SUSTech。
文摘The oxygen reduction reaction (ORR) is the cornerstone reaction of the cathode in metal±air batteries;however,slow kinetics requires high-performance catalysts to promote the reaction.Polyphthalocyanine (PPc) has a typical chemical cross-linking structure and uniformly dispersed metal active sites,but its poor activity and conductivity limit its applications as an ORR catalyst.Herein,a manageable and convenient strategy is proposed to synthesize ternary ORR catalysts through the low-temperature pyrolysis of Fe PPc.The optimal catalyst,Fe_(3)O_(4)/Fe_(3)N/Fe-N-C@PC-2.5,exhibits excellent ORR activity in alkaline solution with a half-wave potential of 0.90 V,which is significantly higher than that of commercial 20%Pt/C (0.84 V).Electrochemical tests and extended X-ray absorption fine structure spectroscopy reveal that the superior ORR activity of Fe_(3)O_(4)/Fe_(3)N/Fe-N-C@PC-2.5 could be ascribed to the balance of its ternary components(i.e.,Fe_(3)O_(4),Fe_(3)N,and Fe-N;species).A Zn±air battery incorporating Fe_(3)O_(4)/Fe_(3)N/Fe-N-C@PC-2.5 as an air cathodic catalyst delivers a high open-circuit voltage and peak power density.During galvanostatic discharge,the battery demonstrates a specific capacity of 815.7 mA h g^(-1).The facile strategy of using PPc to develop high-performance composite electrocatalysts may be expanded to develop new types of catalysts in the energy field.
基金Project(21905220) supported by the National Natural Science Foundation of ChinaProject(BK20201190) supported by the Jiangsu Provincial Department of Science and Technology,China+2 种基金Projects(2018ZDXM-GY-135,2021JLM-36) supported by the Key Research and Development Plan of Shaanxi Province,ChinaProject(HG6J003) supported by the Fundamental Research Funds for “Young Talent Support Plan” of Xi’ an Jiaotong University,ChinaProject supported by the “1000-Plan program” of Shaanxi Province,China。
文摘Lithium-sulfur(Li-S)batteries have been considered as the next generation high energy storage devices.However,its commercialization has been hindered by several issues,especially the dissolution and shuttle of the soluble lithium polysulfides(LiPSs)as well as the slow reaction kinetics of LiPSs which may make shuttling effect even worse.Herein,we report a strategy to address this issue by in-situ transformation of Co−N_(x) coordinations in cobalt polyphthalocyanine(CoPPc)into Co nanoparticles(Co NPs)embedded in carbon matrix and mono-dispersed on graphene flakes.The Co NPs can provide rich binding and catalytic sites,while graphene flakes act as ideally LiPSs transportation and electron conducting platform.With a remarkable enhanced reaction kinetics of LiPSs via these merits,the sulfur host with a sulfur content up to 70 wt%shows a high initial capacity of 1048 mA∙h/g at 0.2C,good rate capability up to 399 mA·h/g at 2C.
基金financially supported by the National Natural Science Foundation of China(Nos.21875221,21571157 and U1604123)the Youth Talent Support Program of High-Level Talents Special Support Plan in Henan Province(No.ZYQR201810148)the Creative Talents in the Education Department of Henan Province(No.19HASTIT039)。
文摘Exploring non-noble metal and high-activity electrocatalysts through a simple and controllable protocol remains a great challenge for oxygen reduction reaction(ORR)and zinc-air batteries.Herein,we developed a melt polymerization strategy to synthesize iron-polyphthalocyanine(FePPc)metallic-organic frameworks(MOFs)over the carbon black matrix(Fe PPc@CB).Through noncovalentπ-πinteractions,Fe PPc molecules can anchor on carbon matrix,thus facilitating the electron transfer process and stabilizing the systems.Owing to abundant free electrons and atomically MN4 catalytic sites in the macrocycle structure,FePPc@CB exhibits excellent oxygen reduction reaction(ORR)and oxygen evolution reaction(OER)electrocatalytic activity.The FePPc@CB also delivers excellent performances for liquid and flexible all-solidstate batteries compared to that of commercial Pt/C,making it a promising ORR/OER electrocatalyst.
