Water adsorption on MnO:ZnO(001) - From single molecules to bilayer coverage

Dalal K. Kanan, John A. Keith, Emily A. Carter

Research output: Contribution to journalArticlepeer-review

6 Scopus citations

Abstract

Improving photochemical water oxidation processes on sunlight absorbing materials requires understanding the photoelectrode-solution interface. We use ab initio density functional theory (DFT) + U to investigate the structure and energetics of water adsorbed on MnO:ZnO(001), a potential photoanode material we previously identified as having suitable band gaps and band edge placements for visible light induced water splitting. Our calculations show that there is a preference for molecular adsorption at water coverages of less than half a monolayer (ML). At higher coverages, cooperative water-water interactions facilitate water dissociation at the interface. We find that the work function is very sensitive to water dipole orientation and/or presence of hydroxyls on the surface. The computed phase diagram reveals the surface to be fairly hydrophilic with a preference for the first water ML to be 33% dissociated at 0.75 ML, 50% dissociated at 1 ML, and 50% dissociated at 2 ML water coverage under various conditions away from water-poor conditions.

Original languageEnglish (US)
Pages (from-to)218-224
Number of pages7
JournalSurface Science
Volume617
DOIs
StatePublished - Nov 2013

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Surfaces, Coatings and Films
  • Materials Chemistry

Keywords

  • Density functional theory
  • Doping
  • Mixed oxides
  • Photocatalysis
  • Water-splitting

Fingerprint Dive into the research topics of 'Water adsorption on MnO:ZnO(001) - From single molecules to bilayer coverage'. Together they form a unique fingerprint.

Cite this