Broad Solar Spectrum-Responsive and Highly Efficient Photoanode of Nonstoichiometric TiO2 Nanoplates/Reduced Graphene Oxide

Mohammad Qamar, Belabbes Merzougui, Muhammad I. Ahmed, Zain H. Yamani

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

Although a photoelectrochemical approach offers one of the most promising processes for solar energy conversion, it still suffers from the unavailability of photocatalysts that can absorb the photons across the ultraviolet-visible region and efficiently generate electron-hole pairs with longer lifetimes. Here, we report the fabrication of heterostructure comprising reduced TiO2 (TiOx) and reduced graphene oxide (RGO) through a facile nonhydrolytic route using benzyl alcohol as a solvent, shape-directing, and a strong reducing agent. Reduction of Ti4+ and graphene oxide was observed in the absence of any additional reducing agent. Nearly monoshaped square nanoplates of TiOx with size in the range of 10-20 nm were formed. Nanoplates consisted of Ti3+ and were capable of absorbing a broad solar spectrum (ultraviolet-visible region). Formation of Ti3+ was confirmed by electron paramagnetic resonance spectroscopy, while a Mott-Schottky plot corroborated the band shift in TiOx. Findings suggest that defects were introduced both on the surface and in the bulk. A plausible mechanism for the formation of TiOx endowed with a reduced metal center is proposed. Photoelectrochemical activity was investigated for water oxidation under visible (λ > 420 nm) or UV-visible (λ = 300-600 nm) radiation and compared with those of anatase TiO2 and nitrogen-doped TiO2. Electrochemical impedance spectroscopy was employed to gain further insights into the electrical conductivity and the charge transfer process in anatase TiO2, N-doped TiO2, and benzyl alcohol-derived TiOx and TiOx/RGO under dark, visible, and UV-visible illuminations.

Original languageEnglish
Pages (from-to)2112-2121
Number of pages10
JournalACS Sustainable Chemistry and Engineering
Volume6
Issue number2
DOIs
Publication statusPublished - 5 Feb 2018

Keywords

  • Benzyl alcohol
  • Nanomaterials
  • Oxygen vacancy
  • Photoelectrochemistry
  • Solar energy
  • Water splitting

ASJC Scopus subject areas

  • Chemistry(all)
  • Environmental Chemistry
  • Chemical Engineering(all)
  • Renewable Energy, Sustainability and the Environment

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