Quantitative XAFS/EELS analyses of nitrogen species in titanium oxide photocatalysts

• DOI: 10.1002/sia.6543
• Publication Date: 2018-09-04T02:33:10Z
• Authors: Tomoko Yoshida; Muenaki Yamamoto; Masato Akatsuka; Akiyo Ozawa; Yuma Kato; Shinya Yagi; Tetsuo Tanabe
• Keywords: Absorbance; XANES; Visible spectrum; Titanium oxide; Absorption edge

With a view to rational designing of highly functional visible‐light TiO 2 photocatalyst, nitrogen atoms were doped into samples by an ion implantation technique which enables control the depth and concentration dopants. Although absorbance in region sample increased doping, photocatalytic activity was not directly connected with photo‐absorbance. The N K‐edge X‐ray absorption near edge structure (XANES) spectrum active (A‐cat) showed characteristic double peak at 398 401 eV, XANES inactive (I‐cat) distinct single around eV. These features spectra well reproduced theoretical simulations based on model where O atom replaced ((N)s) for A‐cat, that quasi NO molecule ((NO )s) I‐cat. Therefore, we have concluded occupying oxygen site is species effective visible light photocatalysis. In addition, quantitative XANES/ELNES analysis has revealed photo‐absorbance ratio I‐cat A‐cat corresponds total rather than concentration. This result indicates only (N)s but also (NO )s absorb light. Thus, necessarily indication response photocatalyst.