O2 activation by AuAg clusters on a defective (100)MgO surface

In the present work, we discuss the electronic properties of supported dispersed bimetallic clusters with respect to their size, geometry, and Aun/Agm (n + m = 6) composition. We have studied with supercell-density functional theory calculations the role of the charge transfer from the MgO defective support toward the cluster in the activation of O2 by AunAgm clusters. We first considered gas-phase clusters with different atomic compositions; then, we deposited all of them on a pristine (100)MgO surface and finally on a more realistic (100)MgO F-center. We performed a global and unrestricted search of the (cluster + surface) geometry. The Mexican enhanced genetic algorithm has been used to exhaustively explore the potential energy surface. Our results show that O2 activation depends on the Aun/Agm ratio. It has been found that both metals involved play different and important roles toward (a) the actual O2 dissociation and (b) weakening of the oxygen-cluster bond, which, in turn, may promote the possibility of a catalytic process to take place, such as the oxidation process of CO and NOx among others.In the present work, we discuss the electronic properties of supported dispersed bimetallic clusters with respect to their size, geometry, and Aun/Agm (n + m = 6) composition. We have studied with supercell-density functional theory calculations the role of the charge transfer from the MgO defective support toward the cluster in the activation of O2 by AunAgm clusters. We first considered gas-phase clusters with different atomic compositions; then, we deposited all of them on a pristine (100)MgO surface and finally on a more realistic (100)MgO F-center. We performed a global and unrestricted search of the (cluster + surface) geometry. The Mexican enhanced genetic algorithm has been used to exhaustively explore the potential energy surface. Our results show that O2 activation depends on the Aun/Agm ratio. It has been found that both metals involved play different and important roles toward (a) the actual O2 dissociation and (b) weakening of the oxygen-cluster bond, which, in turn, may promote the possibili...