The paper focuses on the conductivity of the fuel cell electrolyte in a membraneless glucose-fueled alkaline fuel cell. The electrolyte conductivity is interpreted using simple physical models, considering either the ...The paper focuses on the conductivity of the fuel cell electrolyte in a membraneless glucose-fueled alkaline fuel cell. The electrolyte conductivity is interpreted using simple physical models, considering either the empirical behavior of the solution’s viscosity, or the consideration of ions and molecules colliding in solutions. The conductivity is expressed as a function of KOH and glucose concentrations. The physical properties of the species (i.e. radii, thermal velocity) and the chemical equilibrium constant of the reaction that glucose undergoes in an alkaline solution can be estimate by comparing the experimental results with the theory.展开更多
Platinum catalysts play a major role in the large scale commercialization of direct methanol fuel cells(DMFC).Here,we present a procedure to create a nanostructural graphene-platinum(Gr Pt)composite containing a small...Platinum catalysts play a major role in the large scale commercialization of direct methanol fuel cells(DMFC).Here,we present a procedure to create a nanostructural graphene-platinum(Gr Pt)composite containing a small amount(5.3 wt%)of platinum nanoparticles coated with at least four layers of graphene.The composite,as Gr Pt ink,was deposited on a glassy carbon electrode and its electrocatalytic activity in a methanol oxidation reaction(MOR)was evaluated in a 1 M CH3OH/1 M NaOH solution.The results indicated an enhanced catalytic performance of GrPt towards MOR in alkaline media compared with the Pt/C material.Electron energy-loss spectroscopy and X-ray photoelectron spectroscopy(recorded before and after the electrochemical assays)were employed to analyze the changes in the chemical composition of the nanomaterial and to explain the transformations that took place at the electrode surface.Our findings suggest that growing of graphene on platinum nanoparticles improve the catalytic performance of platinum-graphene composites towards MOR in alkaline media.展开更多
Plasma-synthesized cobalt oxide supported on carbon has been analyzed for its use for electrocatalytic oxygen reduction reaction （ORR） in alkaline anion exchange membrane fuel cells （AEMFC）. This work presents the...Plasma-synthesized cobalt oxide supported on carbon has been analyzed for its use for electrocatalytic oxygen reduction reaction （ORR） in alkaline anion exchange membrane fuel cells （AEMFC）. This work presents the ORR activity in 0.1 mol L-1 KOH and 0.1 tool L-1 K2CO3 at 25 ℃. Cyclic voltammetry （CV） was used to determine the potentials at which the ORR occurs and to evaluate the stability of catalyst. Moreover, a rotating ring-disk electrode （RRDE） was used to investigate the activity of the catalysts and the formation of the by-product hydroperoxide anion （HO2-） as well as to identify the preferred pathway of the ORR. Calculated kinetic parameters for the ORR for the cobalt catalysts are shown in this work together with a comparison to a commercial platinum catalyst. However, the cobalt oxide produced more by-products which could lead to damage of the membrane in a fuel cell through a radical attack of the polymer backbone.展开更多
An environmentally friendly precursor, adenosine, has been used as a dual source of C and N to synthesize nitrogen-doped carbon catalyst with/without Fe. A hydrothermal carbonization method has been used and water is ...An environmentally friendly precursor, adenosine, has been used as a dual source of C and N to synthesize nitrogen-doped carbon catalyst with/without Fe. A hydrothermal carbonization method has been used and water is the carbonization media. The morphology of samples with/without Fe component has been compared by HRTEM, and the result shows that Fe can promote the graphitization of carbon. Further electro-chemical test shows that the oxygen reduction reaction（ORR） catalytic activity of Fe-containing sample（C–Fe N） is much higher than that of the Fe-free sample（C–N）. Additionally, the intermediates of C–Fe N formed during each synthetic procedure have been thoroughly characterized by multiple methods,and the function of each procedure has been discussed. The C–Fe N sample exhibits high electro-catalytic stability and superior electro-catalytic activity toward ORR in alkaline media, with its half-wave potential 20 mV lower than that of commercial Pt/C（40 wt%）. It is further incorporated into alkaline polymer electrolyte fuel cell（APEFC） as the cathode material and led to a power density of 100 m W/cm;.展开更多
文摘The paper focuses on the conductivity of the fuel cell electrolyte in a membraneless glucose-fueled alkaline fuel cell. The electrolyte conductivity is interpreted using simple physical models, considering either the empirical behavior of the solution’s viscosity, or the consideration of ions and molecules colliding in solutions. The conductivity is expressed as a function of KOH and glucose concentrations. The physical properties of the species (i.e. radii, thermal velocity) and the chemical equilibrium constant of the reaction that glucose undergoes in an alkaline solution can be estimate by comparing the experimental results with the theory.
基金financially supported by Romanian National Authority for Scientific Research and Innovation (ANCSI) by NUCLEU Program PN 18 03 02 02
文摘Platinum catalysts play a major role in the large scale commercialization of direct methanol fuel cells(DMFC).Here,we present a procedure to create a nanostructural graphene-platinum(Gr Pt)composite containing a small amount(5.3 wt%)of platinum nanoparticles coated with at least four layers of graphene.The composite,as Gr Pt ink,was deposited on a glassy carbon electrode and its electrocatalytic activity in a methanol oxidation reaction(MOR)was evaluated in a 1 M CH3OH/1 M NaOH solution.The results indicated an enhanced catalytic performance of GrPt towards MOR in alkaline media compared with the Pt/C material.Electron energy-loss spectroscopy and X-ray photoelectron spectroscopy(recorded before and after the electrochemical assays)were employed to analyze the changes in the chemical composition of the nanomaterial and to explain the transformations that took place at the electrode surface.Our findings suggest that growing of graphene on platinum nanoparticles improve the catalytic performance of platinum-graphene composites towards MOR in alkaline media.
文摘Plasma-synthesized cobalt oxide supported on carbon has been analyzed for its use for electrocatalytic oxygen reduction reaction （ORR） in alkaline anion exchange membrane fuel cells （AEMFC）. This work presents the ORR activity in 0.1 mol L-1 KOH and 0.1 tool L-1 K2CO3 at 25 ℃. Cyclic voltammetry （CV） was used to determine the potentials at which the ORR occurs and to evaluate the stability of catalyst. Moreover, a rotating ring-disk electrode （RRDE） was used to investigate the activity of the catalysts and the formation of the by-product hydroperoxide anion （HO2-） as well as to identify the preferred pathway of the ORR. Calculated kinetic parameters for the ORR for the cobalt catalysts are shown in this work together with a comparison to a commercial platinum catalyst. However, the cobalt oxide produced more by-products which could lead to damage of the membrane in a fuel cell through a radical attack of the polymer backbone.
基金supported by the National Natural Science Foundation of China(21173039)Pujiang Foundation of Shanghai,China(08PJ14096)+3 种基金Natural Science Foundation of Shanghai Science and Technology Committee,China(09ZR1433300)Opening Foundation of Zhejing Provincial Top Key Discipline,China(20110927)Scientific Research Foundation for the Returned Overseas Chinese Scholars,Ministry of Education of China(2009(1001))Shanghai Leading Academic Discipline Project Fund,China(B604)~~
基金financially supported by the National Natural Science Foundation of China(21573167,21633008,91545205,21125312)National Key Research and Development Program(2016YFB0101203)+2 种基金the National Basic Research Program(2012CB932800,2012CB215500)the Doctoral Fund of Ministry of Education of China(20110141130002)the Fundamental Research Funds for the Central Universities(2014203020207)
文摘An environmentally friendly precursor, adenosine, has been used as a dual source of C and N to synthesize nitrogen-doped carbon catalyst with/without Fe. A hydrothermal carbonization method has been used and water is the carbonization media. The morphology of samples with/without Fe component has been compared by HRTEM, and the result shows that Fe can promote the graphitization of carbon. Further electro-chemical test shows that the oxygen reduction reaction（ORR） catalytic activity of Fe-containing sample（C–Fe N） is much higher than that of the Fe-free sample（C–N）. Additionally, the intermediates of C–Fe N formed during each synthetic procedure have been thoroughly characterized by multiple methods,and the function of each procedure has been discussed. The C–Fe N sample exhibits high electro-catalytic stability and superior electro-catalytic activity toward ORR in alkaline media, with its half-wave potential 20 mV lower than that of commercial Pt/C（40 wt%）. It is further incorporated into alkaline polymer electrolyte fuel cell（APEFC） as the cathode material and led to a power density of 100 m W/cm;.
