Nickel-Oxide-Modified SrTiO3(110)-(4 × 1) Surfaces and Their Interaction with Water

Stefan Gerhold; Michele Riva; Zhiming Wang; Roland Bliem; Margareta Wagner; Jacek Osiecki; Karina Schulte; Michael Schmid; Ulrike Diebold

doi:10.1021/acs.jpcc.5b06144

Nickel-Oxide-Modified SrTiO₃(110)-(4 × 1) Surfaces and Their Interaction with Water

J Phys Chem C Nanomater Interfaces. 2015 Sep 3;119(35):20481-20487. doi: 10.1021/acs.jpcc.5b06144. Epub 2015 Aug 12.

Authors

Stefan Gerhold¹, Michele Riva², Zhiming Wang³, Roland Bliem¹, Margareta Wagner¹, Jacek Osiecki⁴, Karina Schulte⁴, Michael Schmid¹, Ulrike Diebold¹

Affiliations

¹ Institute of Applied Physics, TU Wien , Wiedner Hauptstraße 8-10, 1040 Vienna, Austria.
² Institute of Applied Physics, TU Wien , Wiedner Hauptstraße 8-10, 1040 Vienna, Austria ; CNISM - Dipartimento di Fisica, Politecnico di Milano , Piazza Leonardo da Vinci 32, I-20133 Milano, Italy.
³ Institute of Applied Physics, TU Wien , Wiedner Hauptstraße 8-10, 1040 Vienna, Austria ; Swiss Light Source, Paul Scherrer Institute , 5234 Villigen, Switzerland.
⁴ MAX IV Laboratory, Lund University , Ole Römers väg 1, 223 63 Lund, Sweden.

Abstract

Nickel oxide (NiO), deposited onto the strontium titanate (SrTiO₃) (110)-(4 × 1) surface, was studied using photoemission spectroscopy (PES), X-ray absorption near edge structure (XANES), and low-energy He⁺ ion scattering (LEIS), as well as scanning tunneling microscopy (STM). The main motivation for studying this system comes from the prominent role it plays in photocatalysis. The (4 × 1) reconstructed SrTiO₃(110) surface was previously found to be remarkably inert toward water adsorption under ultrahigh-vacuum conditions. Nickel oxide grows on this surface as patches without any apparent ordered structure. PES and LEIS reveal an upward band bending, a reduction of the band gap, and reactivity toward water adsorption upon deposition of NiO. Spectroscopic results are discussed with respect to the enhanced reactivity toward water of the NiO-loaded surface.