Hydrogen incorporation by plasma treatment gives mesoporous black TiO2 thin films with visible photoelectrochemical water oxidation activity

Syed Z. Islam, Allen Reed, Suraj Nagpure, Namal Wanninayake, James F. Browning, Joseph Strzalka, Doo Young Kim, Stephen E. Rankin

Research output: Contribution to journalArticlepeer-review

28 Scopus citations

Abstract

Neutron reflectometry (NR) is used to investigate the role of hydrogen in the visible light absorption and enhanced photoactivity for water oxidation of mesoporous black titania thin films. The cubic mesoporous frameworks of TiO2 thin films are prepared by a surfactant-templated sol-gel method and subsequently treated with hydrogen plasma, an approach hypothesized to capitalize on the high degree of disorder in the material and the high energy of the plasma species to achieve efficient hydrogen doping. UV-vis absorbance spectra indicate broad-spectrum visible light absorption in H2 plasma-treated black TiO2 films, and XPS indicates the generation of reduced Ti3+ in the treated films. The presence of hydrogen in black mesoporous titania (H-TiO2) films is confirmed by the scattering length density (SLD) profiles obtained from neutron reflectometry measurements. The H-TiO2 shows ca. 28 times and 8 times higher photocurrent for photoelectrochemical water oxidation compared to undoped TiO2 films under UV (365 nm) and blue (455 nm) LED irradiation, respectively. These findings provide direct evidence that the dramatic change in visible light absorbance of H-treated black TiO2 is accompanied by significant hydrogen uptake and not just Ti3+ generation or surface disordering.

Original languageEnglish
Pages (from-to)35-43
Number of pages9
JournalMicroporous and Mesoporous Materials
Volume261
DOIs
StatePublished - May 1 2018

Bibliographical note

Publisher Copyright:
© 2017 Elsevier Inc.

Keywords

  • Hydrogen doping
  • Mesoporous titania
  • Photocatalysis
  • Plasma treatment
  • Water splitting

ASJC Scopus subject areas

  • General Chemistry
  • General Materials Science
  • Condensed Matter Physics
  • Mechanics of Materials

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