Fig. 2
Exploration of the reactivity of tetrahedral Alβ on γ-Al2O3 (110) from ab initio metadynamics. a, b Structure of the initial surface with chemisorbed water molecules or fragments (the oxygen atoms of which are shown in blue) adsorbed on tetrahedral Alα and Alβ and octahedral Al(1) and Al(2). c Free energy surface obtained from the metadynamics simulation on Alβ using the coordination numbers to alumina oxygen atoms (CNa) and to water molecules and fragments (CNw) as variables. The simulation starts from the point of coordinates (CNa,CNw) = (3,1). d, e Structure of the last intermediate obtained from the hydration of tetrahedral Alβ with (CNa, CNw) = (1,5). f Projected free energy profile with the structure of each intermediate and the corresponding (CNa,CNw). Yellow and white balls represent aluminum and hydrogen atoms, respectively. The color red is used for alumina oxygen atoms and the associated CNa. The color blue is used for water oxygen atoms and the associated CNw
