Novel synthetic route for low-cost carbon-modified TiO2 with enhanced visible light photocatalytic activity: carbon content and calcination effects

• Published in: Journal of sol-gel science and technology Vol. 87; no. 2; pp. 380 - 390
• Main Authors: de Moraes, Nicolas Perciani, da Silva, Maria Lucia Caetano Pinto, Campos, Tiago Moreira Bastos, Thim, Gilmar Patrocínio, Rodrigues, Liana Alvares
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.08.2018; Springer Nature B.V
• Subjects: Anatase; Carbon; Carbon content; Catalytic activity; Ceramics; Chemistry and Materials Science; Composites; Diffuse reflectance spectroscopy; Glass; Heat treatment; Infrared analysis; Infrared spectrophotometers; Inorganic Chemistry; Low cost; Materials Science; Methylene blue; Nanotechnology; Natural Materials; Optical and Electronic Materials; Original paper: Sol-gel and hybrid materials for catalytic; Photocatalysis; photoelectrochemical and sensor applications; Properties (attributes); Raman spectroscopy; Reaction mechanisms; Recycled materials; Scanning electron microscopy; Singlet oxygen; Spectrophotometry; Spectrum analysis; Titanium; Titanium dioxide; Wattle; Tannin; TiO; Photocatalysis; Carbon Xerogel
• ISSN: 0928-0707; 1573-4846
• DOI: 10.1007/s10971-018-4700-4

The aim of this study was the development of low-cost tannin-formaldehyde xerogel/TiO 2 (XTi-w) and carbon xerogel/TiO 2 (XTiC-w) photocatalysts. The materials used as precursors were recycled titanium scraps and black wattle tannin extract, highlighting the low-cost approach employed in the synthesis. The materials were characterized by diffuse reflectance spectroscopy, scanning electron microscopy, dispersive energy spectrophotometry, X-ray diffractometry, infrared and Raman spectroscopy. X-ray diffractometry showed that the XTiC-w have tetragonal crystalline structure (anatase), whereas the XTi-w has an amorphous structure. The Raman and infrared analysis also showed the presence of titanium dioxide in the composition of both XTi-w and XTiC-w. XTi-w and XTiC-w showed photocatalytic activity at the visible wavelength. Titanium dioxide displayed no photocatalytic activity at the visible wavelength. The XTi-60 composite displayed the highest efficiency in the removal of the methylene blue from the system, as well as good reusability properties. The radicals with higher influence in the photocatalytic reaction mechanism are the photo generated electron and the singlet oxygen molecule. The effect of the heat treatment is negative on the photocatalytic properties of the hybrids produced, due to the removal of acid sites, adsorbed water and OH surface groups. The graphical abstract displays an illustration of the materials obtained in this work and their respective efficiency in the adsorption and photocatalytic degradation of methylene blue under visible light. Highlights Hybrids were produced using low-cost materials, such as titanium scraps and tannin Both hybrid materials showed photocatalytic activity at the visible wavelength Heat treatment is negative on the photocatalytic properties of the hybrids Reaction mechanism is controlled by trapped electrons and singlet oxygen molecules