Green synthesis of blue titania nanoparticles by pulsed laser ablation in water

Abstract

This work aimed at using pulsed laser ablation in water (PLAW) for the production of titanium dioxide nanoparticles in water from a commercially pure titanium target. There is great commercial interest in nanotitania, which can be found in products including paints, coatings, textiles, cosmetics, solar panels, and catalysts. Nevertheless, nanotitania is usually obtained through chemical routes, which are cost-intensive and cause a negative environmental impact. PLAW comes as a cleaner option for obtaining nano-TiO2 since it uses only solid titanium and deionized water as raw materials. After the process, an optical micrography of the Ti targets was carried out to assess the interaction of the laser with the metallic surface. The nanoparticles were characterized by DLS, TEM, Raman, XRD, and UV–Vis. Nano-TiO2 activity as a photocatalyst was tested for the degradation of the dye RR141. TEM images point to two populations of produced nanoparticles: one spherical with average sizes between 8 and 13 nm, and one spindle-like with the major axis average ranging between 17 and 35 nm. Composition analyses with XRD and Raman indicate the formation of anatase, rutile, and amorphous titania. The color of the solution produced was bluish, which may indicate the presence of surface defects that extend the light absorption band to the visible range. The catalysis experiments showed suitable results for the UV spectrum, and the calculated bandgaps were close to that of anatase, around 3.2 eV.