Simulations by density functional + implicit classical solvation theories for electrode/solution interfaces under an applied voltage

In order to treat electrochemical reactions at electrode/solution interfaces, the influences of the applied bias voltage should be included in an appropriate computational model. We adopted density functional theory (DFT) with effective screening medium (ESM) method [1] and Laue-represented reference interaction site method (RISM); ESM-RISM method. The former is for applying a voltage and the latter is to represent the electrolyte solution. The ESM-RISM combined with DFT treats the electrode surface by quantum mechanical theory and implicit classical thermodynamics. This formulation automatically contains formation of electronic double layer (EDL) under the applied bias voltage. In the presentation, we will describe the detailed analysis of Pt/water interfaces. Water distribution compared with an experiment, the thickness of the EDL, the potential of zero charge (PZC) vs. standard hydrogen electrode (SHE) potential at Pt(111) surface, and so on, will be discussed. [1] M. Otani and O. Sugino, PRB 73, 115407 (2006). [2] S. Nishihara and M. Otani, PRB 96, 115429 (2017).