Newly synthesized functional nanoparticles,3-amino-1,2,4-triazole(ATA)/SiO_(2)—TiO_(2)were introduced to the polyurethane(PU)matrix.Electrochemical techniques were used to investigate the barrier properties of the sy...Newly synthesized functional nanoparticles,3-amino-1,2,4-triazole(ATA)/SiO_(2)—TiO_(2)were introduced to the polyurethane(PU)matrix.Electrochemical techniques were used to investigate the barrier properties of the synthesized PU—ATA/SiO_(2)—TiO_(2)nanocomposite coated steel specimen.In natural seawater,electrochemical impedance spectroscopy experiments indicated outstanding protective behaviour for the PU—ATA/SiO_(2)—TiO_(2)coated steel.The coating resistance(Rcoat)of PU—ATA/SiO_(2)—TiO_(2)was determined to be 2956.90 kΩ·cm^(−2).The Rcoat of the PU—ATA/SiO_(2)—TiO_(2)nanocomposite coating was found to be over 50%higher than the PU coating.The current measured along the scratched surface of the PU—ATA/SiO_(2)—TiO_(2)coating was found to be very low(1.65 nA).The enhanced ATA/SiO_(2)—TiO_(2)nanoparticles inhibited the entry of electrolytes into the coating interface,as revealed by scanning electron microscopy/energy dispersive X-ray spectroscopy and X-ray diffraction analysis of the degradation products.Water contact angle testing validated the hydrophobic nature of the PU—ATA/SiO_(2)—TiO_(2)coating(θ=115.4°).When the concentration of ATA/SiO_(2)—TiO_(2)nanoparticles was 2 wt%,dynamic mechanical analysis revealed better mechanical properties.Therefore,the newly synthesised PU—ATA/SiO_(2)—TiO_(2)nanocomposite provided excellent barrier and mechanical properties due to the addition of ATA/SiO_(2)—TiO_(2)nanoparticles to the polyurethane,which inhibited material degradation and aided in the prolongation of the coated steel’s life.展开更多
Electrochemical carbon dioxide(CO_(2))reduction(ECR)is a promising technology to produce valuable fuels and feedstocks from CO_(2).Despite large efforts to develop ECR catalysts,the investigation of the catalytic perf...Electrochemical carbon dioxide(CO_(2))reduction(ECR)is a promising technology to produce valuable fuels and feedstocks from CO_(2).Despite large efforts to develop ECR catalysts,the investigation of the catalytic performance and electrochemical behavior of complex metal oxides,especially perovskite oxides,is rarely reported.Here,the inorganic perovskite oxide Ag-doped(La_(0.8)Sr_(0.2))_(0.95)Ag_(0.05)MnO_(3-δ)(LSA0.05M)is reported as an efficient electrocatalyst for ECR to CO for the first time,which exhibits a Faradaic efficiency(FE)of 84.3%,a remarkable mass activity of 75Ag^(-1)(normalized to the mass of Ag),and stability of 130 h at a moderate overpotential of 0.79 V.The LSA0.05M catalyst experiences structure reconstruction during ECR,creating the in operando-formed interface between the perovskite and the evolved Ag phase.The evolved Ag is uniformly distributed with a small particle size on the perovskite surface.Theoretical calculations indicate the reconstruction of LSA0.05M during ECR and reveal that the perovskite-Ag interface provides adsorption sites for CO_(2) and accelerates the desorption of the*CO intermediate to enhance ECR.This study presents a novel high-performance perovskite catalyst for ECR andmay inspire the future design of electrocatalysts via the in operando formation of metal-metal oxide interfaces.展开更多
Cobalt hydroxide nanosheet is among the most popular oxygen evolution reaction(OER)catalyst yet still suffers from sluggish catalytic kinetics,limited activity,and poor stability.Here,an efficient in situ electrochemi...Cobalt hydroxide nanosheet is among the most popular oxygen evolution reaction(OER)catalyst yet still suffers from sluggish catalytic kinetics,limited activity,and poor stability.Here,an efficient in situ electrochemical reconstructed CoFe-hydroxides derived OER electrocatalyst was reported.The introduction of Fe promoted the transformation of Co^(2+)into Co^(3+)in CoFehydroxides nanosheet,along with the formation of abundant amorphous/crystalline interfaces.Thanks for the retained nanosheet microstructure,high valence Co^(3+)and Fe^(3+)species,and the amorphous/crystalline heterostructure interfaces,the as-designed electrochemical reconstructed CoFeOOH nanosheet/Ni foam(CoFeOOHNS/NF)electrode delivers 100 mA·cm^(−2) in alkaline at an overpotential of 275 mV and can stably electrocatalyze water oxidation for at least 35 h at 100 mA·cm^(−2).Meanwhile,the alkaline full water splitting electrolyzer achieves a current density of 10 mA·cm^(−2) only at 1.522 V for CoFeOOHNS/NF‖Pt/C/NF,which is much lower than that of Ru/C/NF‖Pt/C/NF(1.655 V@10 mA·cm^(−2)).This work paves the way for in-situ synergetic modification engineering of electrochemical active components.展开更多
The structure and dynamics of electrode/liquid interfaces play an increasingly important role in electrochemistry. Raman spectroscopy is capable of providing detailed structural information at molecular level and new ...The structure and dynamics of electrode/liquid interfaces play an increasingly important role in electrochemistry. Raman spectroscopy is capable of providing detailed structural information at molecular level and new insight into the interfacial structure, adsorption, reaction, electrocatalysis and corrosion. In this account we will summarize some progresses of surface Raman spectroscopy in the study of electrochemical interfaces, mainly based on our group's work, laying emphasis on the detection sensitivity, spectral resolution, time resolution and spatial resolution as well as the hyphenated technique.展开更多
电化学/电催化技术是实现能源高效转化与储存的重要手段,并已经发展成为一个国际前沿领域。如今日渐深入的电催化研究开始要求更精确且多维度的电化学界面信息,从而指导实现电化学体系的优化,而这往往依赖于一些原位表征方法的发展和应...电化学/电催化技术是实现能源高效转化与储存的重要手段,并已经发展成为一个国际前沿领域。如今日渐深入的电催化研究开始要求更精确且多维度的电化学界面信息,从而指导实现电化学体系的优化,而这往往依赖于一些原位表征方法的发展和应用。电输运谱(electrical transport spectroscopy,ETS)是一种新兴的基于芯片平台的电化学原位表征技术,它可以实现电势扫描条件下电化学信号和电极材料电输运性质的同时获取。本文首先介绍了基于铂纳米线微纳器件的ETS信号原理(吸附现象导致的表面电子散射)和器件制作流程、几个典型电催化反应过程中铂表面状态的演变,以及电解质离子竞争吸附对铂催化氧还原反应动力学过程的影响。由于与电化学体系的高度匹配,ETS可应用于不同结构及金属类型材料体系(金和铂纳米颗粒)。金和铂表现出显著不同的离子吸附现象,尤其是对于弱吸附离子(高氯酸根和硫酸根)。通过电输运谱还可实时监测电化学过程中材料的相变及电子性质的变化。于是,ETS可被用于监测和实现二维材料电化学可控插层,理解电催化剂在电催化过程中的相变机制以及相变过程如何影响电催化活性,揭示二维半导体催化剂材料电催化过程的自门控效应。此外,ETS还被应用于生物电化学体系,探索电化学过程中的细胞导电机制。最后,本文对ETS的优点及不足进行总结,展望了ETS在未来电化学领域所面临的挑战和机遇。展开更多
The incorporation of boron into carbon material can significantly enhance its capacity performances.However,the origin of the promotion effect of boron doping on electrochemical performances is still unclear,in part d...The incorporation of boron into carbon material can significantly enhance its capacity performances.However,the origin of the promotion effect of boron doping on electrochemical performances is still unclear,in part due to the inadequate exposure of boron configurations resulting from the complexity of traditional carbon materials.To overcome this issue,herein,a series of boron-doped graphene with highly-exposed boron configurations are prepared by tuning annealing temperature.Then the correlation between boron configurations and the electrochemical performances is investigated.The combination of density-functional theory(DFT)computation and NH3-TPD/Py-FTIR indicates that the BCO_(2)configuration formed on the surface of graphene is easier to accept lone-pair electrons than BC_(2)O and BC_(3)configurations due to the stronger Lewis acidity.Such an electronic structure can effectively reduce the number of unstable electron donors and stabilize the electrochemical interface,which is proved by NMR,and critical for improving the electrochemical performances.Further experiments confirm that the optimized BG800 with the largest amount of BCO_(2)configuration presents ultralow leak current,improved cyclic stability,and better rate performance in SBPBF4/PC.This work would provide an insight into the design of high-performance boron-doped carbon materials towards energy storage.展开更多
Due to the unique interface and electronic structure,metal/metal oxide composite electrocatalysts have been designed and exploited for electrocatalytic oxygen evolution reaction(OER)in alkaline solution.However,how to...Due to the unique interface and electronic structure,metal/metal oxide composite electrocatalysts have been designed and exploited for electrocatalytic oxygen evolution reaction(OER)in alkaline solution.However,how to fabricate metal/metal oxides with abundant interfaces and well-dispersed metal phases is a challenge,and the synergistic effect between metal and metal oxides on boosting the electrocatalytic activities is still ambiguous.Herein,by controlling the lithium-induced conversion reaction of metal oxides,metal/metal oxide composites with plentiful interfaces and excellent electrical interconnection are fabricated,which can enhance the active sites,and accelerate the mass transfer during the electrocatalytic reaction.As a result,the electrocatalytic oxygen evolution activities of the as-fabricated metal/metal oxide composite catalysts including NiCo/NiCo2O4,NiMn/NiMn2O4 and CoMn/CoMn2O4 are greatly improved.The catalytic mechanism is also explored using the in-situ X-ray and Raman spectroscopic tracking to uncover the real active centers and the synergistic effect between the metal and metal oxides during water oxidation.Density functional theory plus U(DFT+U)calculation confirms the metal in the composite can optimize the catalytic reaction path and reduce the reaction barrier,thus boosting the electrocatalytic kinetics.展开更多
Mechanical property of coarse grained and nano/ultrafine grained alloy 690 and their corrosion resistance after immersion in high temperature borate buffer solution were investigated. The grain refinement significantl...Mechanical property of coarse grained and nano/ultrafine grained alloy 690 and their corrosion resistance after immersion in high temperature borate buffer solution were investigated. The grain refinement significantly enhances the tensile strength of the alloy 690. In addition, the grain refinement facilitates the formation of the deformation twin which improves the ductility of the alloy 690. It has been found that the grain refinement promotes to form more Cr2 O3 on the surface of the alloy 690 in high temperature borate buffer solution. At the same time, the grain refinement inhibits the formation of spinel type oxides.More hematite type oxides formed on nano/ultrafine grained alloy 690 improves its corrosion resistance in borate buffer solution. The hematite type oxides have a lower concentration of point defect than that of the spinel type oxides, which results in an excellent corrosion resistance of nano/ultrafine grained alloy 690. These results are supported by the Mott-Schottky analysis and the point defect model.展开更多
文摘Newly synthesized functional nanoparticles,3-amino-1,2,4-triazole(ATA)/SiO_(2)—TiO_(2)were introduced to the polyurethane(PU)matrix.Electrochemical techniques were used to investigate the barrier properties of the synthesized PU—ATA/SiO_(2)—TiO_(2)nanocomposite coated steel specimen.In natural seawater,electrochemical impedance spectroscopy experiments indicated outstanding protective behaviour for the PU—ATA/SiO_(2)—TiO_(2)coated steel.The coating resistance(Rcoat)of PU—ATA/SiO_(2)—TiO_(2)was determined to be 2956.90 kΩ·cm^(−2).The Rcoat of the PU—ATA/SiO_(2)—TiO_(2)nanocomposite coating was found to be over 50%higher than the PU coating.The current measured along the scratched surface of the PU—ATA/SiO_(2)—TiO_(2)coating was found to be very low(1.65 nA).The enhanced ATA/SiO_(2)—TiO_(2)nanoparticles inhibited the entry of electrolytes into the coating interface,as revealed by scanning electron microscopy/energy dispersive X-ray spectroscopy and X-ray diffraction analysis of the degradation products.Water contact angle testing validated the hydrophobic nature of the PU—ATA/SiO_(2)—TiO_(2)coating(θ=115.4°).When the concentration of ATA/SiO_(2)—TiO_(2)nanoparticles was 2 wt%,dynamic mechanical analysis revealed better mechanical properties.Therefore,the newly synthesised PU—ATA/SiO_(2)—TiO_(2)nanocomposite provided excellent barrier and mechanical properties due to the addition of ATA/SiO_(2)—TiO_(2)nanoparticles to the polyurethane,which inhibited material degradation and aided in the prolongation of the coated steel’s life.
基金Australian Centre for Neutron ScatteringAustralian Nuclear Science and Technology Organisation,Grant/Award Number:MI8046+1 种基金Max Planck-POSTECH-Hsinchu Center for Complex Phase MaterialsHigh-Performance Computing Center of Nanjing Tech University。
文摘Electrochemical carbon dioxide(CO_(2))reduction(ECR)is a promising technology to produce valuable fuels and feedstocks from CO_(2).Despite large efforts to develop ECR catalysts,the investigation of the catalytic performance and electrochemical behavior of complex metal oxides,especially perovskite oxides,is rarely reported.Here,the inorganic perovskite oxide Ag-doped(La_(0.8)Sr_(0.2))_(0.95)Ag_(0.05)MnO_(3-δ)(LSA0.05M)is reported as an efficient electrocatalyst for ECR to CO for the first time,which exhibits a Faradaic efficiency(FE)of 84.3%,a remarkable mass activity of 75Ag^(-1)(normalized to the mass of Ag),and stability of 130 h at a moderate overpotential of 0.79 V.The LSA0.05M catalyst experiences structure reconstruction during ECR,creating the in operando-formed interface between the perovskite and the evolved Ag phase.The evolved Ag is uniformly distributed with a small particle size on the perovskite surface.Theoretical calculations indicate the reconstruction of LSA0.05M during ECR and reveal that the perovskite-Ag interface provides adsorption sites for CO_(2) and accelerates the desorption of the*CO intermediate to enhance ECR.This study presents a novel high-performance perovskite catalyst for ECR andmay inspire the future design of electrocatalysts via the in operando formation of metal-metal oxide interfaces.
基金support from the National Key Research and Development Program of China(No.2020YFB1506300)the National Natural Science Foundation of China(Nos.21625102,21971017,21922502,22075018,51991344,52025025,and 52072400)+1 种基金Beijing Institute of Technology Research Fund Program,The Natural Science Foundation of Hainan Province(No.2019RC166)Beijing Natural Science Foundation(No.Z190010).
文摘Cobalt hydroxide nanosheet is among the most popular oxygen evolution reaction(OER)catalyst yet still suffers from sluggish catalytic kinetics,limited activity,and poor stability.Here,an efficient in situ electrochemical reconstructed CoFe-hydroxides derived OER electrocatalyst was reported.The introduction of Fe promoted the transformation of Co^(2+)into Co^(3+)in CoFehydroxides nanosheet,along with the formation of abundant amorphous/crystalline interfaces.Thanks for the retained nanosheet microstructure,high valence Co^(3+)and Fe^(3+)species,and the amorphous/crystalline heterostructure interfaces,the as-designed electrochemical reconstructed CoFeOOH nanosheet/Ni foam(CoFeOOHNS/NF)electrode delivers 100 mA·cm^(−2) in alkaline at an overpotential of 275 mV and can stably electrocatalyze water oxidation for at least 35 h at 100 mA·cm^(−2).Meanwhile,the alkaline full water splitting electrolyzer achieves a current density of 10 mA·cm^(−2) only at 1.522 V for CoFeOOHNS/NF‖Pt/C/NF,which is much lower than that of Ru/C/NF‖Pt/C/NF(1.655 V@10 mA·cm^(−2)).This work paves the way for in-situ synergetic modification engineering of electrochemical active components.
基金Project supported by the National Nature Science Foundation of China and the Ministry of Education of China.
文摘The structure and dynamics of electrode/liquid interfaces play an increasingly important role in electrochemistry. Raman spectroscopy is capable of providing detailed structural information at molecular level and new insight into the interfacial structure, adsorption, reaction, electrocatalysis and corrosion. In this account we will summarize some progresses of surface Raman spectroscopy in the study of electrochemical interfaces, mainly based on our group's work, laying emphasis on the detection sensitivity, spectral resolution, time resolution and spatial resolution as well as the hyphenated technique.
基金support by the Natural Science Foundation of China (22172075)the Fundamental Research Funds for the Central Universities in China (0210/14380174)the “Innovation and Entrepreneurship” program and Jiangsu Province。
文摘电化学/电催化技术是实现能源高效转化与储存的重要手段,并已经发展成为一个国际前沿领域。如今日渐深入的电催化研究开始要求更精确且多维度的电化学界面信息,从而指导实现电化学体系的优化,而这往往依赖于一些原位表征方法的发展和应用。电输运谱(electrical transport spectroscopy,ETS)是一种新兴的基于芯片平台的电化学原位表征技术,它可以实现电势扫描条件下电化学信号和电极材料电输运性质的同时获取。本文首先介绍了基于铂纳米线微纳器件的ETS信号原理(吸附现象导致的表面电子散射)和器件制作流程、几个典型电催化反应过程中铂表面状态的演变,以及电解质离子竞争吸附对铂催化氧还原反应动力学过程的影响。由于与电化学体系的高度匹配,ETS可应用于不同结构及金属类型材料体系(金和铂纳米颗粒)。金和铂表现出显著不同的离子吸附现象,尤其是对于弱吸附离子(高氯酸根和硫酸根)。通过电输运谱还可实时监测电化学过程中材料的相变及电子性质的变化。于是,ETS可被用于监测和实现二维材料电化学可控插层,理解电催化剂在电催化过程中的相变机制以及相变过程如何影响电催化活性,揭示二维半导体催化剂材料电催化过程的自门控效应。此外,ETS还被应用于生物电化学体系,探索电化学过程中的细胞导电机制。最后,本文对ETS的优点及不足进行总结,展望了ETS在未来电化学领域所面临的挑战和机遇。
基金the National Science Foundation for Excellent Young Scholars of China(21922815)the Key Research and Development(R&D)Projects of Shanxi Province(201903D121007)+3 种基金the Natural Science Foundations of Shanxi Province(201801D221156)the DNL Cooperation Fund of CAS(DNL180308)the Science and Technology Service Network Initiative of CAS(KFJ-STS-ZDTP-068)the Youth Innovation Promotion Association of CAS。
文摘The incorporation of boron into carbon material can significantly enhance its capacity performances.However,the origin of the promotion effect of boron doping on electrochemical performances is still unclear,in part due to the inadequate exposure of boron configurations resulting from the complexity of traditional carbon materials.To overcome this issue,herein,a series of boron-doped graphene with highly-exposed boron configurations are prepared by tuning annealing temperature.Then the correlation between boron configurations and the electrochemical performances is investigated.The combination of density-functional theory(DFT)computation and NH3-TPD/Py-FTIR indicates that the BCO_(2)configuration formed on the surface of graphene is easier to accept lone-pair electrons than BC_(2)O and BC_(3)configurations due to the stronger Lewis acidity.Such an electronic structure can effectively reduce the number of unstable electron donors and stabilize the electrochemical interface,which is proved by NMR,and critical for improving the electrochemical performances.Further experiments confirm that the optimized BG800 with the largest amount of BCO_(2)configuration presents ultralow leak current,improved cyclic stability,and better rate performance in SBPBF4/PC.This work would provide an insight into the design of high-performance boron-doped carbon materials towards energy storage.
基金the National Natural Science Foundation of China(21603157)Young Elite Scientists Sponsorship Program by CAST(2018QNRC001)the support of Suzhou Key Laboratory for Advanced Carbon Materials and Wearable Energy Technologies and Soochow University Analysis and Testing Center。
文摘Due to the unique interface and electronic structure,metal/metal oxide composite electrocatalysts have been designed and exploited for electrocatalytic oxygen evolution reaction(OER)in alkaline solution.However,how to fabricate metal/metal oxides with abundant interfaces and well-dispersed metal phases is a challenge,and the synergistic effect between metal and metal oxides on boosting the electrocatalytic activities is still ambiguous.Herein,by controlling the lithium-induced conversion reaction of metal oxides,metal/metal oxide composites with plentiful interfaces and excellent electrical interconnection are fabricated,which can enhance the active sites,and accelerate the mass transfer during the electrocatalytic reaction.As a result,the electrocatalytic oxygen evolution activities of the as-fabricated metal/metal oxide composite catalysts including NiCo/NiCo2O4,NiMn/NiMn2O4 and CoMn/CoMn2O4 are greatly improved.The catalytic mechanism is also explored using the in-situ X-ray and Raman spectroscopic tracking to uncover the real active centers and the synergistic effect between the metal and metal oxides during water oxidation.Density functional theory plus U(DFT+U)calculation confirms the metal in the composite can optimize the catalytic reaction path and reduce the reaction barrier,thus boosting the electrocatalytic kinetics.
文摘Mechanical property of coarse grained and nano/ultrafine grained alloy 690 and their corrosion resistance after immersion in high temperature borate buffer solution were investigated. The grain refinement significantly enhances the tensile strength of the alloy 690. In addition, the grain refinement facilitates the formation of the deformation twin which improves the ductility of the alloy 690. It has been found that the grain refinement promotes to form more Cr2 O3 on the surface of the alloy 690 in high temperature borate buffer solution. At the same time, the grain refinement inhibits the formation of spinel type oxides.More hematite type oxides formed on nano/ultrafine grained alloy 690 improves its corrosion resistance in borate buffer solution. The hematite type oxides have a lower concentration of point defect than that of the spinel type oxides, which results in an excellent corrosion resistance of nano/ultrafine grained alloy 690. These results are supported by the Mott-Schottky analysis and the point defect model.
