Electrocatalytic reaction systems from

Modeling Electrocatalytic Reaction Systems from First Principles... 

Figure 4.4 Schematic diagram of the free energy calculated from (4.4), Fftee. versus potential cf> for the generic electrocatalytic reaction A —> B. Points indicated hy squares and circles are for specific external charges (various q) for the systems A and B, respectively. Solid and dashed lines indicate the best-fit curves for the free energy versus potential relationship for systems A and B, respectively.

The purpose of this chapter is to selectively summarize recent advances in the molecular modeling of anode and cathode electrocatalytic reactions employing different computational approaches, ranging from first-principles quantum-chemical calculations (based on density functional theory, DFT), ab initio and classical molecular dynamics simulations to kinetic Monte Carlo simulations. Each of these techniques is associated with a proper system size and timescale that can be adequately treated and will therefore focus on different aspects of the reactive system under consideration. 

Aside from the HER and the ORR reactions, nitrides have been studied for a range of other electrocatalytic reactions. A brief summary of a number of these systems follows. 

Electrocatalytic reactions have also been very good model systems for investigating the effects of surface crystalline structure. For example, in electrocatalytic fomuc acid oxidation, the amount of current produced and the extent of surface poisoning were shown to be dependent on the surface structure of the catalyst [4]. The Pt(100) surface produced approximately six times more current than the Pt( 111) surface. The Pt(100) surface suffers from severe poisoning in the forward scan, producing no current (the large current appears only in the backward scan), whereas the Pt(lll) surface displayed little poisoning, as proven by similar oxidation peaks... 

The effect of overpotential on the apparent activation eneigies E of this reaction system is shown in Fig. 70. The apparent activation energies are extracted from In r versus T plots and cannot be attributed specifically to any single reaction step. The observed decrease in Eau with increasing rj with a slope near -1 is in good qualitative agreement with the classical theory of electrocatalytic reactions. ... 

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