Density functional theory carbon-based materials

This chapter focuses on the theoretical modeling studies of ORR catalysts for PEMFC. Theoretical methods, such as density functional theory (DFT) and ab initio molecular dynamics (AIMD) simulation, are presented. Current understanding of ORR mechanism in acidic medium is briefly discussed. Recent theoretical investigations on oxygen reduction electrocatalysts, such as Pt-based catalysts, non-Pt metal catalysts (Pd, Ir, CuCl), and non-precious metal catalysts (transitional metal macrocyclic complexes, conductive polymer materials, and carbon-based materials), are reviewed. The oxygen reduction mechanisms catalyzed by these catalysts are discussed based on the results. 

The mean field density functional theory (DFT) approach was primarily developed by Evans and co-workers [67,68] for studying the interactions of fluids in pores at the molecular level. Recently, DFT methods have been developed specifically with the objective of the estimation of PSD of carbon-based as well as other types of microporous materials. This technique was first proposed by Seaton et al. [16], who used the local-DFT approximation. Later, the theory was modified by Lastoskie et al. [17,18] to incorporate the smoothed or nonlocal DFT approach. The rigorous statistical mechanics basis behind the DFT model has been recently reviewed by Gubbins [34]. Some sahent features of the theory are discussed later in this subsection. The DFT method initially proceeds by estimating the properties of a fluid directly from intermolecular forces such as that between sorbate-sorbent and sorbate-sorbate molecules. The interactions are divided into a short-ranged repulsive part and a long-ranged attractive part, which are both determined separately. 

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