Electrospun Black Titania Nanofibers: Influence of Hydrogen Plasma-Induced Disorder on the Electronic Structure and Photoelectrochemical Performance

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• 作者：A. Lepcha ; C. Maccato ; A. Mettenb枚rger ; T. Andreu ; L. Mayrhofer ; M. Walter ; S. Olthof ; T.-P. Ruoko ; A. Klein ; M. Moseler ; K. Meerholz ; J. R. Morante ; D. Barreca ; S. Mathur
• 刊名：Journal of Physical Chemistry C
• 出版年：2015
• 出版时间：August 20, 2015
• 年：2015
• 卷：119
• 期：33
• 页码：18835-18842
• 全文大小：546K
• ISSN：1932-7455

文摘

This work encompasses a facile method for tailoring surface defects in electrospun TiO₂ nanofibers by employing hydrogen plasma treatments. This amiable processing method was proven with SQUID, EPR, and XPS to be highly effective in generating oxygen vacancies, accompanied by the reduction of Ti⁴⁺ centers to Ti³⁺, resulting in the formation of black titania. The treatment temperature was found to affect the Ti³⁺/Ti⁴⁺ ratios and surface valence, while preserving the original 1D morphology of the titania fibers. Ab initio DFT calculations showed that a high concentration of oxygen vacancies is highly efficient in producing midgap states that enhance the system absorption over the whole visible range, as observed with UV/vis/NIR diffuse reflectance spectroscopy. Pristine TiO₂ nanofibers produced a photocurrent density of 鈭?.02 mA/cm² at 1.23 V vs RHE, whereas the hydrogen plasma treatment resulted in up to a 10-fold increase in the photoelectrochemical performance.