In this paper, 1,2,4-triazolium methanesulfonate （C_2H_4N_3^＋-CH_3SO_3^-, [Tri][MS]）, an ionic conductor, was successfully synthesized. It exhibited high ionic conductivity of 18.60 mS·cm^-1 at 140 ℃ and reac...In this paper, 1,2,4-triazolium methanesulfonate （C_2H_4N_3^＋-CH_3SO_3^-, [Tri][MS]）, an ionic conductor, was successfully synthesized. It exhibited high ionic conductivity of 18.60 mS·cm^-1 at 140 ℃ and reached up to 36.51 mS·cm^-1 at 190 ℃. [Tri][MS] was first applied to modify Nation membrane to fabricate [Tri][MS]/Nafion membrane by impregnation method at 150 ℃. The prepared composite membrane showed high thermal stability with decomposed temperature above 200 ℃ in air atmosphere. In addition, the membrane indicated good ionic conductivity with 3.67 mS·cm^-1 at 140 ℃ and reached up to 13.23 mS·cm^-1 at 180 ℃. The structure of the [Tri][MS] and the composite membrane were characterized by FTIR and the compatibility of [Tri][MS] and Pt/C catalyst was studied by a cyclic voltammetry （CV） method. Besides, the [Tri][MS]/Nafion membrane （thickness of 65 μm） was evaluated with single fuel cell at high temperature and without humidification. The highest power density of [Tri][MS]/Nafion membrane was 3.20 mW·cm^-2 at 140 ℃ and 4.90 mW·cm^-2 at 150 ℃, which was much higher than that of Nation membrane.展开更多
Nafion-stabilized Pt nanoparticle colloidal solution is synthesized through ethylene glycol reduction.Pt/Nafion added with carbon black as electric conduction material（labeled Pt/Nafion-XC72） shows excellent electro...Nafion-stabilized Pt nanoparticle colloidal solution is synthesized through ethylene glycol reduction.Pt/Nafion added with carbon black as electric conduction material（labeled Pt/Nafion-XC72） shows excellent electrochemical property compared with Pt/C.After a 300-cycle discharging durability test,the cell performance of membrane electrode assembly（MEA） with the Pt/Nafion-XC72 and Pt/C catalysts indicates a 29.9% and 92.2% decrease,respectively.The charge transfer resistances of Pt/Nafion-XC72 and Pt/C increase by 27.2% and 101.9%,respectively.The remaining electrochemically active surface area of Pt is about 61.7% in Pt/Nafion-XC72 and about 38.1% in Pt/C after the durability test.The particle size of Pt/C increases from about 5.1 nm to about 10.8 nm but only from 3.6 nm to 5.8 nm in the case of Pt/Nafion-XC72.These data suggest that Pt/Nafion-XC72 as a catalyst can enhance the durability of PEMFCs compared with Pt/C.展开更多
A novel electrophoresis technique, in which a strip of perflurosulfonic-acid (nafion 117) membrane was used to replace the conventional separation column and liquid buffer solution within, was developed and employed t...A novel electrophoresis technique, in which a strip of perflurosulfonic-acid (nafion 117) membrane was used to replace the conventional separation column and liquid buffer solution within, was developed and employed to separate the mixture of dopamine and epinephrine under a low separation voltage of 100 V with quadruple pulses amperometry detection. It was showed that the so-called Nafion membrane electrophoresis could be one of very simple and easy method and has the potentiality to be used to separate and analyze some small organic biologic molecules. Key words nafion membrane - electrophoresis - electrochemical detector - dopamine - epinephrine CLC number O 657. 7 Foundation item: Support by the Foundation of Electroanalytical Chemistry Open Lab (203231510), Changchum, China.Biography: Fang Cheng (1971-), male, Lecture, Ph. D, research direction: Electroanalysis.展开更多
The purpose of the investigation is the study of the physico-chemical properties and electro-catalytic characteristics of the Nafion and MF-4SK membranes with the author’s nanoparticles (A. Revina, 2008) incorporated...The purpose of the investigation is the study of the physico-chemical properties and electro-catalytic characteristics of the Nafion and MF-4SK membranes with the author’s nanoparticles (A. Revina, 2008) incorporated into the perfluoro- sulphonated cationic membranes. An important advance in the creation of new nano-composite materials with poly-functional activity is the inclusion of nanoparticles of various metals (Pd, Pt, Ag) in these membranes. Polymer ion exchange membranes represent widely applicable materials in various areas of modern nanotechnologies. The obtained nanocomposites on the base of included nanoparticles have the perspective properties and polyfunctional activity for the applications.展开更多
The perfluorosulfonic acid(PFSA) membrane doped with two-dimensional conductive filler Ti_(3)C_(2)T_(x) is a fuel cell proton exchange membrane with high application potential. Experimental studies showed that the pro...The perfluorosulfonic acid(PFSA) membrane doped with two-dimensional conductive filler Ti_(3)C_(2)T_(x) is a fuel cell proton exchange membrane with high application potential. Experimental studies showed that the proton conductivity of Nafion/Ti_(3)C_(2)T_(x) composite membrane is improved significantly compared with that in pure Nafion. However, the microscopic mechanism of doping on the enhancement of membrane performance is remain unclear now. In this work, molecular dynamics simulation was used to investigate the microscopic morphology and proton transport behaviors of Nafion/Ti_(3)C_(2)T_(x) composite membrane at the molecular level. The results shown that there were significant differences about the diffusion kinetics of water molecules and hydroxium ions in Nafion/Ti_(3)C_(2)T_(x) at low and high hydration levels in the nanoscale region.With the increase of water content, Ti_(3)C_(2)T_(x) in membrane was gradually surrounded by ambient water molecules to form a hydration layer, and forming a relatively continuous proton transport channel between Nafion polymer and Ti_(3)C_(2)T_(x) monomer. The continuous proton transport channel could increase the number of binding sites of proton and thus achieving high proton conductivity and high mobility of water molecules at higher hydration level. The current work can provide a theoretical guidance for designing new type of Nafion composite membranes.展开更多
Ammonia synthesis by electrocatalytic nitrogen reduction reaction(NRR)is considered as a promising alternative to the Haber−Bosch process.However,due to the extremely low ammonia yield and easily accessible extraneous...Ammonia synthesis by electrocatalytic nitrogen reduction reaction(NRR)is considered as a promising alternative to the Haber−Bosch process.However,due to the extremely low ammonia yield and easily accessible extraneous contamination in the laboratory,NRR study always suffers from fluctuation and variability.Finding and eliminating all kinds of possible extraneous contamination is crucial to evaluate the performance of electrocatalytic ammonia synthesis accurately.In this work,we systematically explored two factors that affect NRR results but are easy to be ignored:the selection of membrane for NRR and the unconscious N-source in NRR catalysts.After series of experiments,we proposed a low-cost and almost pollution-free Celgard 3501 membrane as the separator for NRR to avoid the adsorption and release of ammonia by the membrane.In addition,we proposed a pre-reduction strategy to remove residual or adsorbed NOx contaminants in catalysts.These two solutions will help the community to evaluate the NRR activity more accurately.展开更多
基金financially supported by the National Basic Research Program of China(973 ProgramGrant 2012CB215504)the National Natural Science Foundation of China(21203191 and 21306190)
文摘In this paper, 1,2,4-triazolium methanesulfonate （C_2H_4N_3^＋-CH_3SO_3^-, [Tri][MS]）, an ionic conductor, was successfully synthesized. It exhibited high ionic conductivity of 18.60 mS·cm^-1 at 140 ℃ and reached up to 36.51 mS·cm^-1 at 190 ℃. [Tri][MS] was first applied to modify Nation membrane to fabricate [Tri][MS]/Nafion membrane by impregnation method at 150 ℃. The prepared composite membrane showed high thermal stability with decomposed temperature above 200 ℃ in air atmosphere. In addition, the membrane indicated good ionic conductivity with 3.67 mS·cm^-1 at 140 ℃ and reached up to 13.23 mS·cm^-1 at 180 ℃. The structure of the [Tri][MS] and the composite membrane were characterized by FTIR and the compatibility of [Tri][MS] and Pt/C catalyst was studied by a cyclic voltammetry （CV） method. Besides, the [Tri][MS]/Nafion membrane （thickness of 65 μm） was evaluated with single fuel cell at high temperature and without humidification. The highest power density of [Tri][MS]/Nafion membrane was 3.20 mW·cm^-2 at 140 ℃ and 4.90 mW·cm^-2 at 150 ℃, which was much higher than that of Nation membrane.
基金supported by the National Basic Research Program of China(973 Program,Grant No.2012CB215500the National High-Tech Research and Development Program of China(863 Plan)(No.2012AA052002)the National Natural Science Foundation of China(No.21406024)
文摘Nafion-stabilized Pt nanoparticle colloidal solution is synthesized through ethylene glycol reduction.Pt/Nafion added with carbon black as electric conduction material（labeled Pt/Nafion-XC72） shows excellent electrochemical property compared with Pt/C.After a 300-cycle discharging durability test,the cell performance of membrane electrode assembly（MEA） with the Pt/Nafion-XC72 and Pt/C catalysts indicates a 29.9% and 92.2% decrease,respectively.The charge transfer resistances of Pt/Nafion-XC72 and Pt/C increase by 27.2% and 101.9%,respectively.The remaining electrochemically active surface area of Pt is about 61.7% in Pt/Nafion-XC72 and about 38.1% in Pt/C after the durability test.The particle size of Pt/C increases from about 5.1 nm to about 10.8 nm but only from 3.6 nm to 5.8 nm in the case of Pt/Nafion-XC72.These data suggest that Pt/Nafion-XC72 as a catalyst can enhance the durability of PEMFCs compared with Pt/C.
文摘A novel electrophoresis technique, in which a strip of perflurosulfonic-acid (nafion 117) membrane was used to replace the conventional separation column and liquid buffer solution within, was developed and employed to separate the mixture of dopamine and epinephrine under a low separation voltage of 100 V with quadruple pulses amperometry detection. It was showed that the so-called Nafion membrane electrophoresis could be one of very simple and easy method and has the potentiality to be used to separate and analyze some small organic biologic molecules. Key words nafion membrane - electrophoresis - electrochemical detector - dopamine - epinephrine CLC number O 657. 7 Foundation item: Support by the Foundation of Electroanalytical Chemistry Open Lab (203231510), Changchum, China.Biography: Fang Cheng (1971-), male, Lecture, Ph. D, research direction: Electroanalysis.
文摘The purpose of the investigation is the study of the physico-chemical properties and electro-catalytic characteristics of the Nafion and MF-4SK membranes with the author’s nanoparticles (A. Revina, 2008) incorporated into the perfluoro- sulphonated cationic membranes. An important advance in the creation of new nano-composite materials with poly-functional activity is the inclusion of nanoparticles of various metals (Pd, Pt, Ag) in these membranes. Polymer ion exchange membranes represent widely applicable materials in various areas of modern nanotechnologies. The obtained nanocomposites on the base of included nanoparticles have the perspective properties and polyfunctional activity for the applications.
基金financially supported by the National Key R&D Program of China (Nos.2020YFB1505500 and 2020YFB1505503)。
文摘The perfluorosulfonic acid(PFSA) membrane doped with two-dimensional conductive filler Ti_(3)C_(2)T_(x) is a fuel cell proton exchange membrane with high application potential. Experimental studies showed that the proton conductivity of Nafion/Ti_(3)C_(2)T_(x) composite membrane is improved significantly compared with that in pure Nafion. However, the microscopic mechanism of doping on the enhancement of membrane performance is remain unclear now. In this work, molecular dynamics simulation was used to investigate the microscopic morphology and proton transport behaviors of Nafion/Ti_(3)C_(2)T_(x) composite membrane at the molecular level. The results shown that there were significant differences about the diffusion kinetics of water molecules and hydroxium ions in Nafion/Ti_(3)C_(2)T_(x) at low and high hydration levels in the nanoscale region.With the increase of water content, Ti_(3)C_(2)T_(x) in membrane was gradually surrounded by ambient water molecules to form a hydration layer, and forming a relatively continuous proton transport channel between Nafion polymer and Ti_(3)C_(2)T_(x) monomer. The continuous proton transport channel could increase the number of binding sites of proton and thus achieving high proton conductivity and high mobility of water molecules at higher hydration level. The current work can provide a theoretical guidance for designing new type of Nafion composite membranes.
基金the funding support from the National Thousand Talent Program for Young Professionals and the startup funding from Nankai UniversityThe Overseas Expertise Introduction Project for Discipline Innovation of Higher Education of China(Grant no.B16027)is also acknowledged。
文摘Ammonia synthesis by electrocatalytic nitrogen reduction reaction(NRR)is considered as a promising alternative to the Haber−Bosch process.However,due to the extremely low ammonia yield and easily accessible extraneous contamination in the laboratory,NRR study always suffers from fluctuation and variability.Finding and eliminating all kinds of possible extraneous contamination is crucial to evaluate the performance of electrocatalytic ammonia synthesis accurately.In this work,we systematically explored two factors that affect NRR results but are easy to be ignored:the selection of membrane for NRR and the unconscious N-source in NRR catalysts.After series of experiments,we proposed a low-cost and almost pollution-free Celgard 3501 membrane as the separator for NRR to avoid the adsorption and release of ammonia by the membrane.In addition,we proposed a pre-reduction strategy to remove residual or adsorbed NOx contaminants in catalysts.These two solutions will help the community to evaluate the NRR activity more accurately.
