Control of chemical state of cerium in doped anatase TiO2 by solvothermal synthesis and its application in photocatalytic water reduction

Author(s):Show less -

de Lima, Juliana Fonseca ^{[1, 2]} ; Harunsani, Mohammad Hilni ^[2] ; Martin, David James ^[3] ; Kong, Dan ; Dunne, Peter W. ^[2] ; Gianolio, Diego ^[4] ; Kashtiban, Reza J. ^[5] ; Sloan, Jeremy ^[5] ; Serra, Osvaldo Antonio ^[1] ; Tang, Junwang ^[6] ; Walton, Richard I. ^[2]

Affiliation

^[1] Univ Sao Paulo, FFCLRP, Dept Chem, BR-14040901 Ribeirao Preto, SP - Brazil

^[2] Univ Warwick, Dept Chem, Coventry CV4 7AL, W Midlands - England

^[3] UCL, Dept Chem, London WC1H 0AJ - England

^[4] Diamond Light Source Ltd, Didcot OX11 0DE, Oxon - England

^[5] Univ Warwick, Dept Phys, Coventry CV4 7AL, W Midlands - England

^[6] UCL, Dept Chem Engn, London WC1E 7JE - England

• Document type: Journal article
• Source: JOURNAL OF MATERIALS CHEMISTRY A; v. 3, n. 18, p. 9890-9898, 2015.
• Web of Science Citations: 15

Abstract

Solvothermal synthesis at 240 degrees C in ethanol from titanium(IV) isopropoxide and cerium(III) nitrate hexahydrate produces nanocrystalline powders of anatase-structured TiO2. At low Ce content (0.5 mol% Ti replaced by Ce) the materials contain mixtures of Ce3+ and Ce4+, seen from Ce L-III-edge X-ray absorption near-edge structure (XANES) spectroscopy, which are well dispersed in the anatase structure as evidenced from nanometre-scale electron energy loss spectroscopy maps and powder X-ray diffraction (XRD). The addition of lactic acid to the solvothermal reaction produces less crystalline samples, proved by powder XRD and Raman spectroscopy, with higher surface areas from nitrogen adsorption, and that contain a higher proportion of Ce3+. This leads to material with high activity for photocatalytic hydrogen production from water under UV irradiation in the presence of sacrificial methanol and Pt catalyst. Further in situ XANES experiments at the Ce L-III-edge recorded on heating the materials in air above 300 degrees C shows that oxidation to Ce4+ occurs. This process, typical of the conditions usually used in the synthesis of Ce-doped titania materials, yields materials with lower photocatalytic activity. (AU)

• FAPESP's process: 12/24165-6 - Cerium, titanium, zinc oxide systems: Evaluation of syntheses and structural and morphological properties with photophysical and photochemical applications
• Grantee: Juliana Fonseca de Lima
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 13/11948-5 - Cerium, titanium, zinc oxide systems: crystallization study using X-ray diffraction in situ and morphological and photocatalytic evaluation
• Grantee: Juliana Fonseca de Lima
• Support Opportunities: Scholarships abroad - Research Internship - Post-doctor