Direct Evidence of Surface Reduction in Monoclinic BiVO4

Local measurements of the oxidation state of vanadium in monoclinic BiVO4 particles by means of electron energy-loss spectroscopy in scanning transmission electron microscopy reveal a pronounced surface reduction: within a 5-nm-thick shell, the oxidation state of vanadium is reduced from +5 to about...

Full description

Saved in:
Bibliographic Details
Published inChemistry of materials
Main Authors Rossell, Marta D., Agrawal, Piyush, Borgschulte, Andreas, Hébert, Cécile, Passerone, Daniele, Erni, Rolf
Format Journal Article
LanguageEnglish
Published American Chemical Society 26.05.2015
Online AccessGet full text

Cover

More Information
Summary:Local measurements of the oxidation state of vanadium in monoclinic BiVO4 particles by means of electron energy-loss spectroscopy in scanning transmission electron microscopy reveal a pronounced surface reduction: within a 5-nm-thick shell, the oxidation state of vanadium is reduced from +5 to about +4. Thus, charge neutrality near the surface demands for ∼15% oxygen vacancies. Our results provide direct evidence for the segregation of oxygen vacancies at the surface of BiVO4. This observation is confirmed by X-ray photoelectron spectroscopy. The experimental findings are complemented with all-electron density functional theory based WIEN2k calculations of the density of electron states and of the electron energy-loss near-edge structure. The theoretical results provide further information on the electronic changes induced by the experimentally verified oxygen vacancies.
ISSN:0897-4756
1520-5002
DOI:10.1021/cm504248d