Trap-state passivation of titania nanotubes by electrochemical doping for enhanced photoelectrochemical performance

Lok Kun Tsui, Mikiko Saito, Takayuki Homma, Giovanni Zangari

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31 Citations (Scopus)

Abstract

TiO2 nanotubes are widely investigated materials for photoelectrochemical water splitting, but the presence of trap states limits their performance by facilitating the recombination of electron/hole pairs. In this investigation we unequivocally demonstrate that the photocurrent improvement observed in TiO2 nanotubes after performing electrochemical doping with hydrogen or lithium ions is due to trap state passivation. Specifically, electrochemical impedance spectroscopy evidences that trap state defects disappear upon electrochemical doping, concurrent with an increase in the electron lifetime and faster photocurrent transients. This results in a two-fold enhancement in the photocurrent under simulated sunlight at 1.0 V vs. SCE. Li intercalation was confirmed and the structure as well as the composition of the modified nanotubes was elucidated by GDOES, XPS, and TEM. This journal is

Original languageEnglish
Pages (from-to)360-367
Number of pages8
JournalJournal of Materials Chemistry A
Volume3
Issue number1
DOIs
Publication statusPublished - 2015 Jan 7

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ASJC Scopus subject areas

  • Chemistry(all)
  • Renewable Energy, Sustainability and the Environment
  • Materials Science(all)

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