Pt x Co y Catalysts Degradation in PEFC Environments: Mechanistic Insights I. Multiscale Modeling

In this article, we focus on the understanding of the Pt x CO y electrocatalysts degradation in polymer electrolyte fuel cell (PEFC) environments. A multiscale atomistic/kinetic model is derived providing mechanistic insights on the impact of the nanostructure and operating conditions on Pt x CO y nanoparticles durability. On the basis of ab initio (AI) data, we identify favorable pathways of the oxygen reduction reaction (ORR) on Pt x CO y nanoparticles and of the competitive Pt-Co dissolution in acidic media. The derived AI kinetics is coupled to a description of the atomic reorganization at the nanoparticle level as a function of the cumulated Pt and Co mass losses. This nanoscale model is coupled with a transport microscale model of charges and O 2 through a PEFC cathode, and simulation sensitivity studies to operating conditions and initial compositions/morphologies are performed and complimented by microstructural and electrochemical characterizations carried out on aging direct liquid injection metallorganic chemical vapor deposition elaborated model electrodes detailed in our experimental companion paper.

[1]  P. Balbuena,et al.  Design of oxygen reduction bimetallic catalysts: ab-initio-derived thermodynamic guidelines. , 2005, The journal of physical chemistry. B.

[2]  M. Pruski,et al.  Influence of Hydrogen Chemisorption on the Surface Composition of Pt–Rh/Al2O3Catalysts , 1996 .

[3]  Junliang Zhang,et al.  Origin of enhanced activity in palladium alloy electrocatalysts for oxygen reduction reaction. , 2007, The journal of physical chemistry. B.

[4]  N. Metropolis,et al.  Equation of State Calculations by Fast Computing Machines , 1953, Resonance.

[5]  Bongjin Simon Mun,et al.  Trends in electrocatalysis on extended and nanoscale Pt-bimetallic alloy surfaces. , 2007, Nature materials.

[6]  Jens K. Nørskov,et al.  Electrochemical dissolution of surface alloys in acids: Thermodynamic trends from first-principles calculations , 2007 .

[7]  C. Jallut,et al.  A Multi‐Scale Dynamic Mechanistic Model for the Transient Analysis of PEFCs , 2007 .

[8]  Kwong‐Yu Chan,et al.  Distribution of platinum and cobalt atoms in a bimetallic nanoparticle , 2005 .

[9]  M. Gerard,et al.  Multiscale Model of Carbon Corrosion in a PEFC: Coupling with Electrocatalysis and Impact on Performance Degradation , 2008 .

[10]  H. Jónsson,et al.  Origin of the Overpotential for Oxygen Reduction at a Fuel-Cell Cathode. , 2004, The journal of physical chemistry. B.

[11]  A. Anderson,et al.  Potential Shift for OH(ads) Formation on the Pt Skin on Pt3Co ( 111 ) Electrodes in Acid Theory and Experiment , 2005 .

[12]  Weian Sun.  Particle coarsening: I. Kinetics for reversible dissolution/deposition controlled process , 2005 .

[13]  R. Howe,et al.  An x-ray photoelectron study of metal clusters in zeolites , 1989 .

[14]  H. Gasteiger,et al.  Activity benchmarks and requirements for Pt, Pt-alloy, and non-Pt oxygen reduction catalysts for PEMFCs , 2005 .

[15]  Hubert A. Gasteiger,et al.  Instability of Pt ∕ C Electrocatalysts in Proton Exchange Membrane Fuel Cells A Mechanistic Investigation , 2005 .

[16]  Y. Shao-horn,et al.  Enhanced activity for oxygen reduction reaction on "Pt3Co" nanoparticles: direct evidence of percolated and sandwich-segregation structures. , 2008, Journal of the American Chemical Society.

[17]  James M. Fenton,et al.  Investigation of platinum oxidation in PEM fuel cells at various relative humidities , 2007 .

[18]  A. Anderson,et al.  Cobalt concentration effect in Pt1−xCox on the reversible potential for forming OHads from H2Oads in acid solution , 2005 .

[19]  A. Sutton,et al.  Long-range Finnis–Sinclair potentials , 1990 .

[20]  P. Balbuena,et al.  Adsorption of O, OH, and H2O on Pt-Based Bimetallic Clusters Alloyed with Co, Cr, and Ni , 2004 .

[21]  P. Balbuena,et al.  Dissolution of oxygen reduction electrocatalysts in an acidic environment: density functional theory study. , 2006, The journal of physical chemistry. A.

[22]  Hashem Rafii-Tabar,et al.  Long-range Finnis-Sinclair potentials for f.c.c. metallic alloys , 1991 .

[23]  Masahiro Watanabe,et al.  Activity and Stability of Ordered and Disordered Co‐Pt Alloys for Phosphoric Acid Fuel Cells , 1994 .

[24]  H. Eyring.  The Activated Complex in Chemical Reactions , 1935 .

[25]  F. Calvo,et al.  Numerical simulations of the shape and ‘phase transitions’ in finite systems , 2005 .

[26]  Héctor R. Colón-Mercado,et al.  Stability of platinum based alloy cathode catalysts in PEM fuel cells , 2006 .

[27]  N. Guillet,et al.  Electrogeneration of Hydrogen Peroxide in Acid Medium using Pyrolyzed Cobalt-based Catalysts: Influence of the Cobalt Content on the Electrode Performance , 2006 .

[28]  P. Ross,et al.  CO chemisorption on the 61119 and 61009 oriented single crystal surfaces of the alloy CoPt3*1 , 1990 .

[29]  P. Strasser,et al.  Activity of ordered and disordered Pt-Co alloy phases for the electroreduction of oxygen in catalysts with multiple coexisting phases , 2007 .

[30]  Jiujun Zhang,et al.  Diagnostic tools in PEM fuel cell research: Part I Electrochemical techniques , 2008 .

[31]  Deborah J. Myers,et al.  Effect of voltage on platinum dissolution : Relevance to polymer electrolyte fuel cells , 2006 .

[32]  P. Balbuena,et al.  Surface segregation phenomena in Pt–Pd nanoparticles: dependence on nanocluster size , 2006 .

[33]  The Effect of Metallurgical Variables on the Electrocatalytic Properties of PtCr Alloys , 1987 .

[34]  Ermete Antolini,et al.  The stability of Pt–M (M = first row transition metal) alloy catalysts and its effect on the activity in low temperature fuel cells: A literature review and tests on a Pt–Co catalyst , 2006 .

[35]  Pascal Fugier,et al.  Transient Multi-Scale Modeling of PtxCoy Catalysts Degradation in PEFC Environments , 2008 .

[36]  A. Wokaun,et al.  Oxygen reduction on high surface area Pt-based alloy catalysts in comparison to well defined smooth bulk alloy electrodes , 2002 .

[37]  I. Chorkendorff,et al.  A combined X-Ray photoelectron and Mössbauer emission spectroscopy study of the state of cobalt in sulfided, supported, and unsupported CoMo catalysts , 1982 .

[38]  A. Manthiram,et al.  Effect of Atomic Ordering on the Catalytic Activity of Carbon Supported PtM (M = Fe , Co, Ni, and Cu) Alloys for Oxygen Reduction in PEMFCs , 2005 .

[39]  K. Sundmacher,et al.  The use of CO stripping for in situ fuel cell catalyst characterization , 2007 .

[40]  Yuguang Ma,et al.  Pt surface segregation in bimetallic Pt3M alloys: A density functional theory study , 2008 .

[41]  A. Lasia.  Modeling of hydrogen upd isotherms , 2004 .

[42]  Hubert A. Gasteiger,et al.  Carbon monoxide electrooxidation on well-characterized platinum-ruthenium alloys , 1994 .

[43]  K. Hirokawa,et al.  X-ray photoelectron spectroscopy of Co3O4, Fe3O4, Mn3O4, and related compounds , 1976 .

[44]  S. Zignani,et al.  Evaluation of the stability and durability of Pt and Pt-Co/C catalysts for polymer electrolyte membrane fuel cells , 2008 .

[45]  Robert M. Darling,et al.  Kinetic Model of Platinum Dissolution in PEMFCs , 2003 .

[46]  M. G. Cook,et al.  X-ray photoelectron studies on some oxides and hydroxides of cobalt, nickel, and copper , 1975 .

[47]  F. Weiss,et al.  Synthesis and characterisation of YBCO thin films grown by injection-MOCVD , 1997 .

[48]  Philippe Sautet,et al.  Towards a Multiscale Modeling Methodology for the Prediction of the Electro-Activity of PEM Fuel Cell Catalysts , 2010 .

[49]  Henry Eyring,et al.  The Absolute Rate of Reactions in Condensed Phases , 1935 .

[50]  Ping Yu,et al.  PtCo/C cathode catalyst for improved durability in PEMFCs , 2005 .

[51]  S. Ball,et al.  Mechanisms of Activity Loss in PtCo Alloy Systems , 2007 .

[52]  K. Klabunde,et al.  XPS studies of solvated metal atom dispersed (SMAD) catalysts. Evidence for layered cobalt-manganese particles on alumina and silica , 1991 .

[53]  B. Popov,et al.  Development of method for synthesis of Pt-Co cathode catalysts for PEM fuel cells , 2007 .

[54]  Alejandro A. Franco,et al.  CO Induced Reconstruction of PtxCoy Electrocatalytic Nanoparticles in a PEM Fuel Cell Anode under Transportation Operating Conditions , 2010 .

[55]  Tomoki Akita,et al.  Platinum dissolution and deposition in the polymer electrolyte membrane of a PEM fuel cell as studied by potential cycling. , 2006, Physical chemistry chemical physics : PCCP.

[56]  M. Seah,et al.  Pure element sputtering yields using 500–1000 eV argon ions , 1981 .

[57]  M. Koper,et al.  Co-adsorption of water and hydroxyl on a Pt2Ru surface , 2006 .

[58]  A. Franco,et al.  Transient multiscale modeling of aging mechanisms in a PEFC cathode , 2007 .

[59]  A. Dolati,et al.  A study on the kinetic of the electrodeposited Co–Ni alloy thin films in sulfate solution , 2007 .

[60]  P. Balbuena,et al.  Density functional theory study of adsorption of OOH on Pt-based bimetallic clusters alloyed with Cr, Co, and Ni , 2005 .

[61]  Yang Shao-Horn,et al.  Formation Mechanism of Pt Single-Crystal Nanoparticles in Proton Exchange Membrane Fuel Cells , 2007 .

[62]  S. Badrinarayanan,et al.  Photoelectron-spectroscopic study of nickel, manganese and cobalt selenides , 1984 .

[63]  Ling Zhu,et al.  Effects of Chemisorption on the Surface Composition of Bimetallic Catalysts , 1997 .

[64]  Bernhard Maschke,et al.  A Dynamic Mechanistic Model of an Electrochemical Interface , 2006 .

[65]  E. Snoeck,et al.  H2-induced structural evolution in non-crystalline rhodium nanoparticles , 2001 .

[66]  S. Ball,et al.  PtCo, a Durable Catalyst for Automotive PEMFC? , 2007 .