Phase transformations, vacancy formation and variations of optical and photocatalytic properties in TiO2-ZnO composites by high-pressure torsion

Jacqueline Hidalgo-Jimenez, Qing Wang, Kaveh Edalati, Jorge M. Cubero-Sesín, Hadi Razavi-Khosroshahi, Yoshifumi Ikoma, Dionisio Gutiérrez-Fallas, Fernando A. Dittel-Meza, Juan Carlos Rodríguez-Rufino, Masayoshi Fuji, Zenji Horita

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

TiO2 and ZnO, two semiconductors with promising optical properties, are considered as potential candidates for solar and photocatalytic applications. Although chemical methods have been primarily used to enhance the optical properties of these oxides, the current authors recently reported enhanced photocatalytic performance of pure TiO2 and ZnO by plastic straining due to the generation of high-pressure phases and oxygen vacancies. In this study, to improve the optical properties further, large fractions of ZnO/TiO2 interphase boundaries are also introduced by application of high-pressure torsion (HPT) straining to a mixture of anatase-TiO2 and wurtzite-ZnO powders. It was found that the amounts of oxygen vacancies and nanograined high-pressure TiO2-II and rocksalt-ZnO phases increase with increasing plastic strain. Moreover, due to the plastic strain effect, the rutile-TiO2 phase is formed at room temperature, which is at least 600 »K below the reported anatase-to-rutile transition temperature. These structural features, together with the formation of large fraction of interphase boundaries, lead to electron spin resonance, optical bandgap narrowing, diminishing of the band-to-band photoluminescence and thus, improvement of photocatalytic hydrogen generation. Despite improvements in the photocatalytic activity of TiO2-ZnO composites after large straining, photocatalytic activity becomes poor by processing at ultra-large strains due to the significant reduction in crystallinity.

Original languageEnglish
Pages (from-to)170-185
Number of pages16
JournalInternational Journal of Plasticity
Volume124
DOIs
Publication statusPublished - Jan 2020

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Torsional stress
Vacancies
Optical properties
Phase transitions
Oxygen vacancies
Titanium dioxide
Plastic deformation
Composite materials
Optical band gaps
Superconducting transition temperature
Paramagnetic resonance
Photoluminescence
Powders
Oxides
Semiconductor materials
Plastics
Hydrogen
Processing
titanium dioxide
Temperature

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering

Cite this

Phase transformations, vacancy formation and variations of optical and photocatalytic properties in TiO2-ZnO composites by high-pressure torsion. / Hidalgo-Jimenez, Jacqueline; Wang, Qing; Edalati, Kaveh; Cubero-Sesín, Jorge M.; Razavi-Khosroshahi, Hadi; Ikoma, Yoshifumi; Gutiérrez-Fallas, Dionisio; Dittel-Meza, Fernando A.; Rodríguez-Rufino, Juan Carlos; Fuji, Masayoshi; Horita, Zenji.

In: International Journal of Plasticity, Vol. 124, 01.2020, p. 170-185.

Research output: Contribution to journalArticle

Hidalgo-Jimenez, J, Wang, Q, Edalati, K, Cubero-Sesín, JM, Razavi-Khosroshahi, H, Ikoma, Y, Gutiérrez-Fallas, D, Dittel-Meza, FA, Rodríguez-Rufino, JC, Fuji, M & Horita, Z 2020, 'Phase transformations, vacancy formation and variations of optical and photocatalytic properties in TiO2-ZnO composites by high-pressure torsion', International Journal of Plasticity, vol. 124, pp. 170-185. https://doi.org/10.1016/j.ijplas.2019.08.010
Hidalgo-Jimenez, Jacqueline ; Wang, Qing ; Edalati, Kaveh ; Cubero-Sesín, Jorge M. ; Razavi-Khosroshahi, Hadi ; Ikoma, Yoshifumi ; Gutiérrez-Fallas, Dionisio ; Dittel-Meza, Fernando A. ; Rodríguez-Rufino, Juan Carlos ; Fuji, Masayoshi ; Horita, Zenji. / Phase transformations, vacancy formation and variations of optical and photocatalytic properties in TiO2-ZnO composites by high-pressure torsion. In: International Journal of Plasticity. 2020 ; Vol. 124. pp. 170-185.
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AU - Razavi-Khosroshahi, Hadi

AU - Ikoma, Yoshifumi

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