EXPLORATION OF TM-NX ORR ELECTROCATALYSTS FROM FIRST PRINCIPLE CALCULATIONS
Fuel Cells are promising candidates for the energy conversion technologies in particular for non-stationary applications. However, current fuel cells rely on rare and expensive Platinum catalysts and the power generation is limited by the sluggish oxygen reduction reaction (ORR) at the cathode. An interesting alternative material set which continues to attract significant attention are TM-Nx (TM = Fe, Co, x = 2 - 4) based non-PGM electrocatalysts where the defect motifs are embedded in a carbon matrix during pyrolysis. By studying the material properties of individual defects we can determine how the chemistry and morphology of these TM-Nx motifs are interdependent. Additional focus will also be on XPS characterization for the identification of the nature of proposed catalytic site(s). Although XPS is a widely used experimental technique for this purpose, the unique identification of structural motifs from XPS observations alone remains challenging. vi First-principles computations can provide us with the missing link by predicting core-level shifts for candidate defect motifs. This ability enables us to establish structure/property relationships directly and provides us with information that is critical for the detailed interpretation of XPS spectra. The incentive of this research thesis resides in the understanding of the electrochemical performance and energetics of these TM-Nx catalysts and the quest for the design of suitable catalysts with improved performance.
DFT computation of Nitrogen functionalized transition metal electrocatalysts
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