X-ray Photoelectron Spectroscopy and Resonant X-ray Spectroscopy Investigations of Interactions between Thin Metal Catalyst Films and Amorphous Titanium Dioxide Photoelectrode Protection Layers

Matthias H. Richter, Wen Hui Cheng, Ethan J. Crumlin, Walter S. Drisdell, Harry A. Atwater, Dieter Schmeißer, Nathan S. Lewis, Bruce S. Brunschwig

Research output: Contribution to journalArticlepeer-review

Abstract

The use of electrochemistry, X-ray photoelectron spectroscopy, and resonant X-ray spectroscopy has unlocked the paradox of interfacial hole conduction through amorphous TiO2 (a-TiO2) to deposited Ni, Ir, and Au metal catalysts. Although electrocatalysts for the oxygen-evolution reaction derived from metallic Ir and Ni have mutually similar overpotentials in alkaline media, Si/a-TiO2/Ir interfaces exhibit higher overpotentials than Si/a-TiO2/Ni interfaces. The data allow formulation of full band energy diagrams for n-Si/a-TiO2/metal interfaces for M = Ni, Ir, or Au. Although both Ni and Ir produce band bending in a-TiO2 favoring hole conduction, only Ni creates multiple states within the a-TiO2 band gap at the a-TiO2/Ni interface, which produces a quasi-metallic interface at the a-TiO2/Ni junction. Au, however, produces a flat-band interface that limits hole conduction without any new band gap states.

Original languageEnglish
Pages (from-to)1265-1275
Number of pages11
JournalChemistry of Materials
Volume33
Issue number4
DOIs
Publication statusPublished - Feb 23 2021

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Materials Chemistry

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