Orbital dependent interaction of quantum well states for catalytic water splitting

Orientational dependence of catalytic activity for water splitting reaction on a two-dimensional gold cluster supported on MgO/Ag(001) has been identified using first-principles calculations. Strong oscillations are found in water adsorption energy, the dissociation barrier, and the binding energy of the dissociated H atom, with two different orientational patterns. These two patterns correlate with the wavefunction symmetry of frontier orbitals of selected quantum well states (QWSs). This finding reveals a new aspect of orbital symmetry in catalytic reactions without involving changes in the shape or size of the atomic cluster, and is promising for potential applications in chemical reactions using the orbital degree of freedom of QWSs. (paper)