Application of first principles methods in the study of fuel cell air-cathode electrocatalysis

Abstract

First principles modeling has enjoyed widespread use in many traditional areas of chemistry (e.g., organic, inorganic) for decades and its success has made it an indispensable tool in these areas. Use of first principles modeling in electrochemistry, however, is a recent story. This delay has largely been due to complex interface problems. Nevertheless, with recent advances in computer technology and electronic structure calculation algorithms, quantum chemistry calculation is rapidly becoming a necessary tool in the field of electrochemistry. Several publications and reviews on quantum chemistry methodologies in electrochemistry and surface reaction are available [1-8]. To understand electron transfer at a metal-solution interface, it is essential to have microscopic information about the equilibrium and nonequilibrium structure of the solvent, the specific adsorption of ions, and the state of reactants and products near the charged surface of a metal. However, despite tremendous developments in the modern experimental in situ method, experimentally probing the interface process is still a challenge. Therefore, theoretical modeling can play an important role, as it complements experimental measurements and offers the possibility of providing a detailed description of the interface process at the atomistic and molecular levels. In recent years, the number of publications on the application of the first principles methods in the area of fuel cell electrocatalysis has grown significantly. Electrocatalyst material is one of the major obstacles for fuel cell technology. The widely used catalyst, Pt, suffers from several drawbacks, namely slow kinetics, low efficiency, high cost, and limited abundance in the earths crust. Development of new catalyst materials with low cost, high performance, and durability is the goal. This chapter concentrates on the first principles studies of fuel cell air-cathode electrocatalysts, i.e., oxygen reduction reaction (ORR) electrocatalysis. Recent progress in theoretical methodologies will be introduced and the current status of first principles studies of the ORR will be reviewed. The chapter is organized as follow: first, the background theory and the oxygen reduction reaction will be introduced, and then theoretical applications in the study of the ORR will be reviewed in four sections, according to theoretical approach. In each section, the computational method is presented with examples, the research findings from theoretical studies are discussed, and the capabilities of the present quantum chemistry methods are illustrated. © 2008 Springer-Verlag.