Electrocatalysis and Catalyst Screening from Density Functional Theory Calculations - Fuel Cell Catalysis: A Surface Science Approach - page 56

& CHAPTER 3
Electrocatalysis and Catalyst
Screening from Density Functional
Theory Calculations
J. ROSSMEISL
Center for Atomic-Scale Materials Design, NanoDTU, Department of Physics, Technical University of
Denmark, DK-2800 Kongens Lyngby, Denmark
J. GREELEY
Center for Nanoscale Materials, Argonne National Laboratory, Argonne, IL 60439, USA
G.S. KARLBERG
Center for Atomic-Scale Materials Design, NanoDTU, Department of Physics, Technical University of
Denmark, DK-2800 Kongens Lyngby, Denmark
3.1 INTRODUCTION
A realistic atomistic description of electrochemical reactions taking place at the
water - metal interface is a very demanding task from a computational point of view.
To begin with, it is necessary to describe the adsorption of atoms and molecules on
the surface. This part of the task is analogous to the description of chemical processes
in heterogeneous catalysis, for which quite detailed calculations based mainly on density
function theory (DFT) are beginning to appear [Behler et al., 2005; Bucko et al., 2005;
Hensen et al., 2005; Honkala et al., 2005; Kieken et al., 2005; Xu et al., 2005; Zellner
et al., 2005]. In addition, the description of electrochemical reactions at the water -
solid interface presents a number of new challenges; solvation effects due to the presence
of water, effects of the applied bias, and effects due to counter-ions. Finally, nonadiabatic
effects in connection with electron transfer may be important. Recently a number of
different approaches have been proposed to handle various aspects of these challenges
[Filhol and Neurock, 2006; Koper, 2005; Nørskov et al., 2004; Roques et al., 2005].
Whereas electrochemistry is a very rich and many-facetted science, we will focus
here on systems with metal electrodes in contact with acid or alkaline solutions.