Differentiating electro-catalytic reaction of hydride with respect to a non-Pt catalyst morphology based on first-principles: extended surfaces versus nanoparticles

摘要

We conducted first-principles electronic structure calculations and ab-initio molecular dynamics (MD) based on density functional theory (DFT) to obtain the fundamental electrocatalytic properties of a hydride (borohydride) adsorption on a non-Pt catalyst (Osmium) with respect to catalyts' facet and morphology. We found that the binding energy and the structure of the borohydride change with respect to the Os-2nm facets: (1010) , (1100) , (0001). These fundamental properties can predict the reactivity of such facets under electrochemcial environment. We note that the electro-catalytic activity of the Os decreases in the following order: (1010) ＞ (1100) ＞ (0001) following the same trend in the binding energies. With respect to the catalyst morphology (extended surface vs nanoparticle), the reactivity is predicted by the combined effect of the strength of interaction of both the borohydride and the water molecule. On the otherhand, the size of the nanoparticle is found to affect the binding energy of the borohydride via the significant change in the nanoparticle structure due to temperature. These results are seen to provide valuabe insights in the design of new catalyts systems for borohydride oxidation as well as in the modeling of nanoparticle catalysts under electrochemical conditions.