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DFT Simulations of Water Adsorption and Activation on Low‐Index α‐Ga 2 O 3 Surfaces
Author(s) -
Zhou Xin,
Hensen Emiel J. M.,
van Santen Rutger A.,
Li Can
Publication year - 2014
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201400006
Subject(s) - adsorption , density functional theory , degree of unsaturation , chemistry , chemical physics , binding energy , hydrogen , relaxation (psychology) , molecular dynamics , computational chemistry , atomic physics , physics , organic chemistry , psychology , social psychology
Density functional theory (DFT) calculations are used to explore water adsorption and activation on different α‐Ga 2 O 3 surfaces, namely (001), (100), (110), and (012). The geometries and binding energies of molecular and dissociative adsorption are studied as a function of coverage. The simulations reveal that dissociative water adsorption on all the studied low‐index surfaces are thermodynamically favorable. Analysis of surface energies suggests that the most preferentially exposed surface is (012). The contribution of surface relaxation to the respective surface energies is significant. Calculations of electron local density of states indicate that the electron‐energy band gaps for the four investigated surfaces appears to be less related to the difference in coordinative unsaturation of the surface atoms, but rather to changes in the ionicity of the surface chemical bonds. The electrochemical computation is used to investigate the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) on α‐Ga 2 O 3 surfaces. Our results indicate that the (100) and (110) surfaces, which have low stability, are the most favorable ones for HER and OER, respectively.