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Stability of La dopants in NaTaO3 photocatalysts

Authors: 

Hanggara Sudrajat*, Sandhya Babel, Indika Thushari, Kritapas Laohhasurayotin

Source title: 
Journal of Alloys and Compounds, 775: 1277-1285, 2019 (ISI)
Academic year of acceptance: 
2018-2019
Abstract: 

Doping NaTaO3 with La typically results in increased photocatalytic activity. The photocatalytic activity of La-doped NaTaO3 should therefore be sensitive to the photostability of the La species being doped. Unfortunately, the photostability of the La species in NaTaO3 is not fully known. Herein, we perform an in-depth study on the photostability of the La species. Advanced characterization techniques, including X-ray photoelectron spectroscopy (XPS), X-ray absorption near edge structure (XANES), and extended X-ray absorption fine structure (EXAFS), are employed to clarify the chemical state and local structure of the La species in NaTaO3. Our findings show that the examined La-doped NaTaO3 can be effectively reused for six consecutive runs without a significant loss of its photocatalytic activity for the decomposition of recalcitrant organic compounds under UV light. The reusability of La-doped NaTaO3 is proposed to be due to the photostability of the La species. The La species are photostable because their oxidation state is unaltered and their structure in the host NaTaO3 is well preserved.