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

IF 1.7 4区材料科学 Q2 MATERIALS SCIENCE, CERAMICS Journal of Electroceramics Pub Date : 2021-11-11 DOI:10.1007/s10832-021-00273-4

Mahdi Hajihashemi, Morteza Shamanian, Fakhreddin Ashrafizadeh

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引用次数: 1

Abstract

Optical and photocatalytic applications of Al₂O₃ and TiO₂ 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, Al₂O₃-TiO₂ 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 (Al₂TiO₅) during sintering greatly affected the absorption of Al₂O₃-TiO₂ 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.

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火花等离子烧结氧空位诱导Al2O3-TiO2陶瓷的带隙调谐

Al2O3和TiO2陶瓷的光学和光催化应用受到限制，特别是在可见光下，由于其宽的带隙;因此，该参数在这些应用中起着重要甚至决定性的作用。本研究采用火花等离子烧结(SPS)技术，在1573 K下烧结Al2O3-TiO2球磨粉末。采用XRD、SEM、UV-Vis和电化学等方法对产物进行了表征。结果表明，复合材料在可见光下的吸光能力有效提高(高达95%)，并且由于氧空位的增加，带隙减小到2.2 eV，这是由于烧结过程中气氛的减少。此外，烧结过程中新相(Al2TiO5)的形成，由于载流子分离中心分数的增加，极大地影响了Al2O3-TiO2复合材料在可见光区的吸收。光致发光光谱也表明钛石的形成可以有效地提高电荷分离效率。

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来源期刊

Journal of Electroceramics 工程技术-材料科学：硅酸盐

CiteScore

2.80

自引率

5.90%

发文量

审稿时长

5.7 months

期刊介绍： While ceramics have traditionally been admired for their mechanical, chemical and thermal stability, their unique electrical, optical and magnetic properties have become of increasing importance in many key technologies including communications, energy conversion and storage, electronics and automation. Electroceramics benefit greatly from their versatility in properties including: -insulating to metallic and fast ion conductivity -piezo-, ferro-, and pyro-electricity -electro- and nonlinear optical properties -feromagnetism. When combined with thermal, mechanical, and chemical stability, these properties often render them the materials of choice. The Journal of Electroceramics is dedicated to providing a forum of discussion cutting across issues in electrical, optical, and magnetic ceramics. Driven by the need for miniaturization, cost, and enhanced functionality, the field of electroceramics is growing rapidly in many new directions. The Journal encourages discussions of resultant trends concerning silicon-electroceramic integration, nanotechnology, ceramic-polymer composites, grain boundary and defect engineering, etc.