Center for Functional Nanomaterials Seminar
"First principles molecular dynamics of metal/water interfaces under bias potential"
Presented by Dr. Luana Pedroza
Thursday, February 20, 2014, 1:30 pm
CFN, Bldg., 735, Conf. Rm. A
Hosted by: Deyu Lu
Center for Functional Nanomaterials Seminar Dr. Luana Pedroza First principles molecular dynamics of metal/water interfaces under bias potential Thursday, February 20, 2014 1:30 p.m. Bldg. 735 â€" Conf. Rm. A Understanding the interaction of the water-metal system at an atomic level is extremely important in electrocatalysis for fuel cells applications and electrodes for hydrogen evolution in photocatalysis, among other systems. This involves a detailed study of the nature of the interactions between water-water and water-substrate. A first principles description of all components of the system is the most appropriate methodology to be used, because there is rather limited experimental evidence of the microscopic description of these complex electrochemical interfaces. In this work we analyze in detail the structural, dynamic and energetic properties of liquid-water interacting with Au and Pd (111) surfaces at ambient temperature, using first principles molecular dynamics. In the case of Au, the simulations are performed both in the presence and absence of an external bias potential applied to the electrodes, as one would come across in electrochemistry. This is accomplished by using a combination of density functional theory (DFT) and non-equilibrium Green's functions methods (NEGF), thus simulating a realistic out-of-equilibrium open system. We show that, contrary to what was found when studying ice-like water layers, van der Waals interactions play a critical role in modeling the aqueous/electrode interface. We show the differences in the ordering of water at the interface for Pd and Au, and we explain the change in work functions of these two metals in aqueous solution. Host: Deyu Lu Joann Tesoriero Center for Functional Nan