Ab initio study of oxygen reduction mechanism at Pt(4) cluster.

We used density functional theory to investigate the reaction pathway of oxygen reduction/water splitting at a tetrahedral Pt(4) cluster. Four extra water molecules were included to account for the effect of water in mediating elementary surface processes. We propose a 6-step reaction sequence that includes a proton transfer between neighbouring active sites. Thermochemical considerations and the nudged elastic band method were employed to calculate reaction and activation energies for the elementary reaction steps. We generated the free energy diagram along the reaction path for various applied potentials. This plot provides vital information on the stability of intermediates and the rate determining processes in oxygen reduction and water splitting. Results suggest that removal of the reaction product, viz. molecular oxygen or water, is an energetically strongly hindered step in either direction.

[1]  J. Medlin,et al.  Mechanistic study of the electrochemical oxygen reduction reaction on Pt(111) using density functional theory. , 2006, The journal of physical chemistry. B.

[2]  Gadi Rothenberg,et al.  Catalysis and Electrocatalysis at Nanoparticle Surfaces , 2004 .

[3]  J. Nørskov,et al.  Electrolysis of water on (oxidized) metal surfaces , 2005 .

[4]  A. Damjanović,et al.  Distinction between Intermediates Produced in Main and Side Electrodic Reactions , 1966 .

[5]  John P. Perdew,et al.  Molecular and solid‐state tests of density functional approximations: LSD, GGAs, and meta‐GGAs , 1999 .

[6]  M. Eikerling,et al.  Kinetic modeling of CO(ad) monolayer oxidation on carbon-supported platinum nanoparticles. , 2006, The journal of physical chemistry. B.

[7]  K. Kinoshita,et al.  Electrochemical Oxygen Technology , 1992 .

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

[9]  Christopher D. Taylor,et al.  Calculated phase diagrams for the electrochemical oxidation and reduction of water over Pt(111). , 2006, The journal of physical chemistry. B.

[10]  A. Miyazaki,et al.  Effect of platinum morphology on lean reduction of NO with C3H6 , 2004 .

[11]  H. Stanley,et al.  Hydrogen-bond dynamics of water in a quasi-two-dimensional hydrophobic nanopore slit. , 2009, Physical review. E, Statistical, nonlinear, and soft matter physics.

[12]  Jackson,et al.  Atoms, molecules, solids, and surfaces: Applications of the generalized gradient approximation for exchange and correlation. , 1992, Physical review. B, Condensed matter.

[13]  Matthew Neurock,et al.  First-Principles Analysis of the Initial Electroreduction Steps of Oxygen over Pt(111) , 2009 .

[14]  T. Jacob.  The Mechanism of Forming H2O from H2 and O2 over a Pt Catalyst via Direct Oxygen Reduction , 2006 .

[15]  Kresse,et al.  Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set. , 1996, Physical review. B, Condensed matter.

[16]  William A Goddard,et al.  Agostic interactions and dissociation in the first layer of water on Pt(111). , 2004, Journal of the American Chemical Society.

[17]  Jens K Nørskov,et al.  Surface Pourbaix diagrams and oxygen reduction activity of Pt, Ag and Ni(111) surfaces studied by DFT. , 2008, Physical chemistry chemical physics : PCCP.

[18]  S. Mukerjee.  Particle size and structural effects in platinum electrocatalysis , 1990 .

[19]  G. Henkelman,et al.  Improved tangent estimate in the nudged elastic band method for finding minimum energy paths and saddle points , 2000 .

[20]  P N Ross,et al.  The impact of geometric and surface electronic properties of pt-catalysts on the particle size effect in electrocatalysis. , 2005, The journal of physical chemistry. B.

[21]  M. Eikerling,et al.  Hydrogen Evolution at a Single Supported Nanoparticle: A Kinetic Model , 2003 .

[22]  J Rossmeisl,et al.  Estimations of electric field effects on the oxygen reduction reaction based on the density functional theory. , 2007, Physical chemistry chemical physics : PCCP.

[23]  A. Panchenko,et al.  Ab Initio calculations of intermediates of oxygen reduction on low-index platinum surfaces , 2004 .

[24]  Manos Mavrikakis,et al.  Improved oxygen reduction reactivity of platinum monolayers on transition metal surfaces , 2008 .

[25]  G. Kresse,et al.  Ab initio molecular dynamics for liquid metals. , 1993 .

[26]  Werner Scholz,et al.  A path method for finding energy barriers and minimum energy paths in complex micromagnetic systems , 2002 .

[27]  R. O. Jones,et al.  The density functional formalism, its applications and prospects , 1989 .

[28]  H. Jónsson,et al.  Origin of the Overpotential for Oxygen Reduction at a Fuel-Cell Cathode , 2004 .

[29]  A. Anderson,et al.  Advancements in the local reaction center electron transfer theory and the transition state structure in the first step of oxygen reduction over platinum , 2005 .

[30]  Andrzej Wieckowski,et al.  Catalysis and Electrocatalysis at Nanoparticle Surfaces , 2003 .

[31]  Junliang Zhang,et al.  Intrinsic kinetic equation for oxygen reduction reaction in acidic media: the double Tafel slope and fuel cell applications. , 2008, Faraday discussions.

[32]  Ju Li,et al.  Near neutrality of an oxygen molecule adsorbed on a Pt(111) surface. , 2008, Physical review letters.

[33]  Philip N. Ross,et al.  Oxygen Reduction Reaction on Pt and Pt Bimetallic Surfaces: A Selective Review , 2001 .

[34]  S. Mukerjee,et al.  Site-Specific vs Specific Adsorption of Anions on Pt and Pt-Based Alloys , 2007 .

[35]  C. Hartnig,et al.  Molecular dynamics simulation of the first electron transfer step in the oxygen reduction reaction , 2002 .

[36]  S. Mukerjee,et al.  Effect of particle size on the electrocatalysis by carbon-supported Pt electrocatalysts: an in situ XAS investigation , 1998 .

[37]  W. Schirmer,et al.  Introduction to Surface Chemistry and Catalysis , 1995 .

[38]  V. Radmilović,et al.  Oxygen Reduction on Carbon-Supported Pt−Ni and Pt−Co Alloy Catalysts , 2002 .

[39]  K. Kreuer.  Proton Conductivity: Materials and Applications , 1996 .

[40]  Michael Eikerling,et al.  Water in polymer electrolyte fuel cells: Friend or foe? , 2006 .

[41]  Michael Eikerling,et al.  Ab Initio Study of Stability and Site-Specific Oxygen Adsorption Energies of Pt Nanoparticles , 2009 .

[42]  Hubert A. Gasteiger,et al.  Handbook of Fuel Cells , 2010 .