Nano Research

, Volume 7, Issue 10, pp 1528–1547 | Cite as

Self-assembly of nitrogen-doped TiO2 with exposed {001} facets on a graphene scaffold as photo-active hybrid nanostructures for reduction of carbon dioxide to methane

  • Wee-Jun Ong
  • Lling-Lling Tan
  • Siang-Piao ChaiEmail author
  • Siek-Ting Yong
  • Abdul Rahman Mohamed
Research Article


Tailored synthesis of well-defined anatase TiO2-based crystals with exposed {001} facets has stimulated incessant research interest worldwide due to their scientific and technological importance. Herein, anatase nitrogen-doped TiO2 (N-TiO2) nanoparticles with exposed {001} facets deposited on the graphene (GR) sheets (N-TiO2-001/GR) were synthesized for the first time via a one-step solvothermal synthetic route using NH4F as the morphology-controlling agent. The experimental results exemplified that GR was uniformly covered with anatase N-TiO2 nanoparticles (10–17 nm), exposing the {001} facets. The percentage of exposed {001} facets in the N-TiO2-001/GR nanocomposites was calculated to be ca. 35%. Also, a red shift in the absorption edge and a strong absorption in the visible light range were observed due to the formation of Ti-O-C bonds, resulting in the successful narrowing of the band gap from 3.23 to 2.9 eV. The photocatalytic activities of the as-prepared photocatalysts were evaluated for CO2 reduction to produce CH4 in the presence of water vapor under ambient temperature and atmospheric pressure using a low-power 15 W energy-saving daylight lamp as the visible light source—in contrast to the most commonly employed high-power xenon lamps—which rendered the process economically and practically feasible. Among all the studied photocatalysts, the N-TiO2-001/GR nanocomposites exhibited the greatest CH4 yield of 3.70 μmol·gcatalyst −1, approximately 11-fold higher activity than the TiO2-001. The enhancement of photocatalytic performance was ascribed to the effective charge anti-recombination of graphene, high absorption of visible light region and high catalytic activity of {001} facets relative to the {101} facets.


photocatalysis nitrogen-doped TiO2 {001} facet acid treated solvent exfoliated graphene carbon dioxide reduction visible light 


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Copyright information

© Tsinghua University Press and Springer-Verlag Berlin Heidelberg 2014

Authors and Affiliations

  • Wee-Jun Ong
    • 1
  • Lling-Lling Tan
    • 1
  • Siang-Piao Chai
    • 1
    Email author
  • Siek-Ting Yong
    • 1
  • Abdul Rahman Mohamed
    • 2
  1. 1.Low Carbon Economy (LCE) Group, Chemical Engineering Discipline, School of EngineeringMonash University, Jalan Lagoon SelatanBandar Sunway, SelangorMalaysia
  2. 2.Low Carbon Economy (LCE) Group, School of Chemical EngineeringUniversiti Sains Malaysia, Engineering Campus, Seri AmpanganNibong Tebal, Pulau PinangMalaysia

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