Band gap tuning of oxygen vacancy-induced Al2O3-TiO2 ceramics processed by spark plasma sintering

Optical and photocatalytic applications of Al 2 O 3 and TiO 2 ceramics are limited, especially under visible light, due to their wide bandgap; so, this parameter plays an important and even decisive role in these applications. In the present study, Al 2 O 3 -TiO 2 ball milled powders were sintered b...

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Bibliographic Details
Published in:Journal of electroceramics 2022-02, Vol.48 (1), p.35-50
Main Authors: Hajihashemi, Mahdi, Shamanian, Morteza, Ashrafizadeh, Fakhreddin
Format: Article
Language:English
Subjects:
Aluminum oxide
Aluminum titanates
Ball milling
Ceramics
Characterization and Evaluation of Materials
Charge efficiency
Chemistry and Materials Science
Composite materials
Composites
Crystallography and Scattering Methods
Current carriers
Electrochemistry
Electromagnetic absorption
Energy gap
Glass
Materials Science
Natural Materials
Optical and Electronic Materials
Oxygen
Photoluminescence
Plasma sintering
Separation
Sintering (powder metallurgy)
Spark plasma sintering
Titanium dioxide
Vacancies
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Summary:Optical and photocatalytic applications of Al 2 O 3 and TiO 2 ceramics are limited, especially under visible light, due to their wide bandgap; so, this parameter plays an important and even decisive role in these applications. In the present study, Al 2 O 3 -TiO 2 ball milled powders were sintered by spark plasma sintering (SPS) at 1573 K. The products were characterized using XRD, SEM, UV–Vis and electrochemical methods. The results indicated effective improvement in the light absorbing capability of the composites (up to 95%) under visible light and the decrease of the band gap down to 2.2 eV owing to the increase of oxygen vacancies, which was, in turn, due to the reduced atmosphere of the sintering process. In addition, formation of a new phase (Al 2 TiO 5 ) during sintering greatly affected the absorption of Al 2 O 3 -TiO 2 composites in the visible light region due to the increase in the fraction of the charge carrier separation centers. Photo-luminescence spectroscopy also showed that tialite formation could be effective in improving the charge separation efficiency.
ISSN:1385-3449
1573-8663
DOI:10.1007/s10832-021-00273-4