2015/12/21 by Daniel Halwidl, Bernhard Stöger, Wernfried Mayr-Schmölzer +9 · 77 citations
Materials Science · Physics and Astronomy · #Adsorption #Advancements in Solid Oxide Fuel Cells #Cleave #Electronic and Structural Properties of Oxides #Hydroxide #Magnetic and transport properties of perovskites and related materials #Molecule #Monolayer #Monomer #Oxide #Perovskite (structure) #cond-mat.mtrl-sci
paper · pdf · doi:10.1038/nmat4512
published in Nature Materials 15(4), 450-455 (Nature Portfolio)
openalex publication_date 2015/12/21 · openalex created_date 2016/06/24 · arxiv created 2018/04/16 · arxiv updated 2018/04/17 · openalex updated_date 2026/08/05
Although perovskite oxides hold promise in applications ranging from solid oxide fuel cells to catalysts, their surface chemistry is poorly understood at the molecular level. Here we follow the formation of the first monolayer of water at the (001) surfaces of Srn+1RunO3n+1 (n = 1, 2) using low-temperature scanning tunnelling microscopy, X-ray photoelectron spectroscopy, and density functional theory. These layered perovskites cleave between neighbouring SrO planes, yielding almost ideal, rocksalt-like surfaces. An adsorbed monomer dissociates and forms a pair of hydroxide ions. The OH stemming from the original molecule stays trapped at Sr-Sr bridge positions, circling the surface OH with a measured activation energy of 187 ± 10 meV. At higher coverage, dimers of dissociated water assemble into one-dimensional chains and form a percolating network where water adsorbs molecularly in the gaps. Our work shows the limitations of applying surface chemistry concepts derived for binary rocksalt oxides to perovskites.