Defect engineering toward strong photocatalysis of Nb-doped anatase TiO2: Computational predictions and experimental verifications

Sovann Khan, Haneol Cho, Donghun Kim, Sang Soo Han, Kyu Hwan Lee, So Hye Cho, Taeseup Song, Heechae Choi

Research output: Contribution to journalArticlepeer-review

40 Citations (Scopus)

Abstract

Understanding the roles of point defects in optical transitions is a key to the desirable engineering of photochemical materials. In this study, the origins of the significantly varying optical and photochemical properties of Nb-doped anatase TiO2were systematically investigated, using density functional theory (DFT) calculations and experimental verifications. We found from DFT calculations that the desirable band gap reduction of anatase TiO2by ∼0.1 eV reported in many of experimental reports and the resultant improvements of photocatalytic and photovoltaic efficiencies of Nb5+-doped anatase TiO2are due to the formation of complex (NbTi-VTi)3−as the compensator of NbTi+. Our experiments demonstrated that the O2-rich annealing, which is expected to increase the concentration of desirable (NbTi-VTi)3−complex, narrows band gap of TiO2and strongly enhances the photocatalytic activity of Nb-doped TiO2particle. On the contrary, pure TiO2showed rather worse photocatalytic performances when annealed in O2-rich atmosphere, which is due to the formation of deep level by O-interstitial defect (Oi). Theoretically obtained charge effective masses could further explain the different photocatalytic activities of undoped and Nb-doped TiO2.

Original languageEnglish
Pages (from-to)520-530
Number of pages11
JournalApplied Catalysis B: Environmental
Volume206
DOIs
Publication statusPublished - 2017
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Environmental Science(all)
  • Process Chemistry and Technology

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