AI_ML_DL’s diary






2020年度からは、「この度、新たにNEDOからECCEED’30-FCプロジェクト(※3) ECCEED’40-FCプロジェクト(※4)を受託しました。2020年度からこれまでの成果を活かしながら新たな発想を取り入れることにより、NEDO技術マップ等で定められるシナリオに基づき、高効率、高耐久、低コストの燃料電池システムを実現するための技術を開発します。」





J. K. Nørskov et al., Origin of the Overpotential for Oxygen Reduction at a Fuel-Cell Cathode, J. Phys. Chem. B, 108, 17886 (2004)


In the following, we use density functional theory (DFT) calculations to gain some insight into the cathode reactions.

DFT calculations can provide information about the stability of surface intermediates in the reactions, which cannot be easily obtained by other means.

We start by considering the simplest possible reaction mechanism over a Pt(111) surface.

We introduce a method for calculating the free energy of all intermediates as a function of the electrode potential directly from density functional theory calculations of adsorption energies for the surface intermediates.

On this basis, we establish an overview of the thermodynamics of the cathode reaction as a function of voltage, and we show that the overpotential of the reaction can be linked directly to the proton and electron transfer to adsorbed oxygen or hydroxide being strongly bonded to the surface at the electrode potential where the overall cathode reaction is at equilibrium.

We introduce a database of density functional theory calculations of energies of the surface intermediates for a number of metals and show that, on this basis, we can establish trends in the thermodynamic limitations for all the metals in question.

The model predicts a volcano-shaped relationship between the rate of the cathode reaction and the oxygen adsorption energy.

The model explains why Pt is the best elemental cathode material and why alloying can be used to improve its performance.







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