Details

Autor(en) / Beteiligte

• Kohlrausch, Emerson C
• Zapata, Maximiliano JM
• Goncalves, Renato V
• Khan, Sherdil
• Vaz, Mauricio de O
• Dupont, Jairton
• Teixeira, Sergio R
• Leite Santos, Marcos J

Titel

Polymorphic phase study on nitrogen-doped TiO sub(2) nanoparticles: effect on oxygen site occupancy, dye sensitized solar cells efficiency and hydrogen production

Ist Teil von

• RSC advances, 2015-11, Vol.5 (123), p.101276-101286

Erscheinungsjahr

2015

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• In this work we show that phase formation and oxygen substitution can be controlled by the source of nitrogen used during the synthesis of TiO sub(2) nanoparticles. By performing a thorough study on the structure of the nanoparticles, the use of NH sub(4) super(+) or NO sub(3) super(-) was found to influence not only the N-doping level but also the formation of the polymorphic phase. Structural and microstructural refinement obtained by XRD pattern and data processing performed by the Rietveld refinement revealed that TiO sub(2) obtained with HNO sub(3) presents ca.98% of anatase and ca.2% for rutile. Meanwhile TiO sub(2) nanoparticles synthesized with NH sub(4)F and NH sub(4)Cl presents a single anatase phase with ca.7.0% and 4.4% of nitrogen substitutional oxygen sites, respectively. The local structure of N-doped TiO sub(2) around the Ti atoms was investigated by X-ray absorption spectroscopy. The XANES spectra show that N-doped TiO sub(2) possesses a characteristic pre-edge of a single anatase structure. The coordination number decreased and the shrinking Ti-O bond distances are due to the N-doping in the TiO sub(2) structure. The most efficient dye sensitized solar cell and the higher hydrogen production was obtained from the TiO sub(2)/NH sub(4)Cl, which was obtained as a single anatase phase with intermediary concentration of N substitutional oxygen sites.