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Electrochemical Phenomena (electrochemical + phenomenon)
Selected AbstractsElectrochemical Phenomena in the Nanoworld/Molecular Devices and Machines/Surface Science/Spectroscopic Advances/Chemistry at a Historic CrossroadsCHEMPHYSCHEM, Issue 1 2009Christian Amatore Prof. Dr. First page of article [source] Mathematical modeling of solid oxide fuel cells at high fuel utilization based on diffusion equivalent circuit modelAICHE JOURNAL, Issue 5 2010Cheng Bao Abstract Mass transfer and electrochemical phenomena in the membrane electrode assembly (MEA) are the core components for modeling of solid-oxide fuel cell (SOFC). The general MEA model is simply governed with the Stefan-Maxwell equation for multicomponent gas diffusion, Ohm's law for the charge transfer and the current-overpotential equation for the polarization calculation. However, it has obvious discrepancy at high-fuel utilization or high-current density. An advanced MEA model is introduced based on the diffusion equivalent circuit model. The main purpose is to correct the real-gas concentrations at the triple-phase boundary by assuming that the resistance of surface diffusion is in series with that of the gaseous bulk diffusion. Thus, it can obtain good prediction of cell performance in a wide range by avoiding the decrement of effective gas diffusivity via unreasonable increment of the electrode tortuosity in the general MEA model. The mathematical model has been validated in the cases of H2H2O, COCO2 and H2CO fuel system. © 2009 American Institute of Chemical Engineers AIChE J, 2010 [source] Numerical analysis of thermal and electrochemical phenomena for anode supported microtubular SOFCAICHE JOURNAL, Issue 3 2009Daan Cui Abstract A 2D model considering momentum, heat/species transport and electrochemical phenomena, has been proposed for tubular solid oxide fuel cell. The model was validated using experimental polarization curves and the good agreement with the experimental data was attained. The temperature distributions show that temperature varies severely at the tube inlet than at the tube outlet. The heat generation and transfer mechanisms in electrodes, electrolyte and electrochemical reaction interface were investigated. The results show that the overall electrochemical reaction heat is produced at cathode/electrolyte interface, and a small portion of the heat is consumed at anode/electrolyte interface. The heat produced at cathode/electrolyte interface is about five times as much as that consumed at anode/electrolyte interface. Overwhelming part of the heat transfer between cell and outside occurs at cathode external surface. Most current flow goes into anode from a very small area where the current collectors locates. © 2009 American Institute of Chemical Engineers AIChE J, 2009 [source] Mathematical modeling for the ionic inclusion process inside conducting polymer-based thin-filmsPOLYMER ENGINEERING & SCIENCE, Issue 11 2008Saptarshi Majumdar Ionic inclusion inside thin conducting polymer (CP) film is a major and common feature for actuator as well as membrane-based drug release. In this study, an electro-active polymeric thin-film system has been conceptualized. PNP-electro-neutrality (Poisson,Nernst, Planck) based modeling framework with customized boundary conditions is used to depict the electrochemical phenomena. In dynamic model, kinetics of probable redox reactions is included along with electro-migration and diffusion terms in the overall PNP framework. At steady state, interfacial voltage seems to hold the critically important role, while ionic migration and reaction kinetics play very crucial roles in determining the dynamics of such systems. The validated model predicts that lowering in the standard potential of the polymeric electrode accelerates the process of ionic ingress. Higher ionic flux is obtained using slower voltage scan. Variation of diffusivity shows the large spectrum of relatively unexplored dynamics for such electro-active thin-film-based system. The significance is in designing actuator- or membrane-based controlled molecular release systems. POLYM. ENG. SCI., 2008. © 2008 Society of Plastics Engineers [source] | ||||||||||