Multiple Heterojunction in Single Titanium Dioxide Nanoparticles for Novel Metal-Free Photocatalysis

Yoonjun Cho, Sungsoon Kim, Bumsu Park, Chang Lyoul Lee, Jung Kyu Kim, Kug Seung Lee, Il Yong Choi, Jong Kyu Kim, Kan Zhang, Sang Ho Oh, Jong Hyeok Park

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44 Citations (Scopus)


Despite a longstanding controversy surrounding TiO2 materials, TiO2 polymorphs with heterojunctions composed of anatase and rutile outperform individual polymorphs because of the type-II energetic band alignment at the heterojunction interface. Improvement in photocatalysis has also been achieved via black TiO2 with a thin disorder layer surrounding ordered TiO2. However, localization of this disorder layer in a conventional single TiO2 nanoparticle with the heterojunction composed of anatase and rutile has remained a big challenge. Here, we report the selective positioning of a disorder layer of controlled thicknesses between the anatase and rutile phases by a conceptually different synthetic route to access highly efficient novel metal-free photocatalysis for H2 production. The presence of a localized disorder layer within a single TiO2 nanoparticle was confirmed for the first time by high-resolution transmission electron microscopy with electron energy-loss spectroscopy and inline electron holography. Multiple heterojunctions in single TiO2 nanoparticles composed of crystalline anatase/disordered rutile/ordered rutile layers give the nanoparticles superior electron/hole separation efficiency and novel metal-free surface reactivity, which concomitantly yields an H2 production rate that is ∼11-times higher than that of Pt-decorated conventional anatase and rutile single heterojunction TiO2 systems.

Original languageEnglish
Pages (from-to)4257-4262
Number of pages6
JournalNano letters
Issue number7
Publication statusPublished - 2018 Jul 11

Bibliographical note

Funding Information:
J.H.P. acknowledges the support by the NRF of Korea Grant funded by the Ministry of Science, ICT & Future Planning (2016R1A2A1A05005216, 2016M3D3A1A01913254, 2015M1A2A2074663). S.H.O. acknowledges the support for the TEM work by the Creative Materials Discovery Program (NRF-2015M3D1A1070672), Bio-inspired Innovation Technology Development Project (NRF-2018M3C1B7021994) through the National Research Foundation of Korea (NRF) of the Ministry of Science, the ICT and Future Planning, and Industrial Technology Innovation Program (10080654) of the Ministry of Trade, Industry & Energy (MOTIE, Korea). K.S.L. acknowledges support by the Nano-Material Fundamental Technology Development program (2017M3A7B4049173) through the National Research Foundation of Korea (NRF). K.Z. acknowledges support by “the Fundamental Research Funds for the Central Universities” (No. 30918011106).

Publisher Copyright:
© 2018 American Chemical Society.

All Science Journal Classification (ASJC) codes

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering


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