Combined modification of a TiO2 photocatalyst with two different carbon forms

• Published in: Applied surface science Vol. 270; pp. 675 - 684
• Main Authors: Ansón-Casaos, Alejandro, Tacchini, Ignacio, Unzue, Andrea, Martínez, M. Teresa
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.04.2013; Elsevier
• Subjects: Anatase; Carbon; Carbon nanotubes; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Glucose; Nanocomposite; Nanorod; Nanotubes; Photocatalysis; Physics; Single wall carbon nanotubes; Titanates; Titanium dioxide; Visible; X-rays; Carbon nanotubes; Visible; Nanocomposite; Titanium dioxide; Nanorod; Photocatalysis; Inorganic compounds; Transition element compounds; Carbon; Composite materials; Nanocomposites; Titanium oxide; Nanostructured materials
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2013.01.120

► We synthesized a new ternary SWCNT/C/TiO2 nanocomposite photocatalyst. ► Interactions between carbon and titanium were characterized by XPS and IR. ► The ternary photocatalyst showed a substantial activity under visible light. ► The different carbon forms induced different photocatalytic mechanisms. Hydrothermally synthesized titanate nanotubes were carbon-doped through a thermal treatment in the presence of glucose followed by blending with single-walled carbon nanotubes (SWCNTs). A series of TiO2-based materials was prepared with various initial glucose contents and two SWCNT types, resulting in total carbon contents from 0.3wt.% to nearly 26wt.%. Electron microscopy observations indicated that titanate nanotubes were converted into nanorods during the thermal treatment, and X-ray diffraction patterns confirmed that all the treated materials mostly consisted of anatase TiO2. Glucose pyrolysis caused changes in the infrared and X-ray photoelectron spectra of the titania material, indicating an interaction between the inserted carbon atoms and titanium atoms. Raman spectra of SWCNT/C/TiO2 hybrids showed characteristic bands of both the SWCNT and anatase TiO2 phases. SWCNT/C/TiO2 multicomponent materials demonstrated substantially better photocatalytic activities than P25 TiO2 for methylene blue degradation under visible light irradiation. Independently from its origin, the presence of carbon caused a strong increase in the TiO2 visible light absorption. However, the results obtained with the C/TiO2 and SWCNT/C/TiO2 photocatalysts clearly showed different photocatalysis mechanisms depending on the carbon form.