Ab Initio Investigation of Water Adsorption and Hydrogen Evolution on Co <inf>9</inf> S <inf>8</inf> and Co <inf>3</inf> S <inf>4</inf> Low-Index Surfaces
- Publication Type:
- Journal Article
- ACS Omega, 2018, 3 (9), pp. 12215 - 12228
- Issue Date:
Copyright © 2018 American Chemical Society. We used density functional theory approach, with the inclusion of a semiempirical dispersion potential to take into account van der Waals interactions, to investigate the water adsorption and dissociation on cobalt sulfide Co 9 S 8 and Co 3 S 4 (100) surfaces. We first determined the nanocrystal shape and selected representative surfaces to analyze. We then calculated water adsorption and dissociation energies, as well as hydrogen and oxygen adsorption energies, and we found that sulfur vacancies on Co 9 S 8 (100) surface enhance the catalytic activity toward water dissociation by raising the energy level of unhybridized Co 3d states closer to the Fermi level. Sulfur vacancies, however, do not have a significant impact on the energetics of Co 3 S 4 (100) surface.
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