Tuning Adsorption via Strain and Vertical Ligand Effects

Abstract

We report on the structure and electrochemical adsorption properties of well-defined pseudomorphic Pt mono- and multilayers on Ru(0001). These act as model surfaces for Pt(111) with slightly decreased affinity to adsorbed hydrogen (H_ad) and hydroxyl (OH_ad). In cyclic voltammograms, this is reflected in more negative/positive potential regions for the reversible adsorption of upd-H_ad/OH_ad, respectively, compared to Pt(111). For upd-H_ad, we show that the corresponding trends can be predicted with high accuracy by density functional theory (DFT). In particular, the upd-H_ad onset regions can be precisely simulated using the H_ad adsorption energies from DFT, the layer thickness distribution from STM, and the base voltammogram of Pt(111) as reference.