Green synthesis of mesoporous anatase TiO₂nanoparticles and their photocatalytic activities

Abstract

Titanium dioxide (TiO 2 ) materials have been the focus of many promising applications due to their low-cost, availability and biocompatible properties. In this study, mesoporous anatase TiO 2 nanoparticles were synthesised using a green chemistry approach. This visible-light active photocatalyst was prepared via a simple and solvent free precipitation method at low temperatures using titanium tetraisopropoxide (TTIP) as a precursor and soluble starch as the template. The effect of initial solution pH and concentration of TTIP on surface morphology and photocatalytic activities of TiO 2 nanoparticles were evaluated. Based on the results obtained, the TiO 2 nanocatalyst prepared using 0.01 mol of TTIP under basic conditions revealed the best photocatalytic activity. The as-synthesised nanoparticles were further characterised using X-ray powder diffraction (XRD), scanning electron microscopy (SEM) and nitrogen adsorption analysis (NAA). The XRD spectrum confirmed that the catalyst was composed of anatase tetragonal TiO 2 phase. The Brunauer-Emmett-Teller (BET) surface area of 81.59 m 2 g À1 proved the presence of mesopores (average pore size ¼ 8.7 nm) which partially contributed to and catalysed the photodegradation process of methylene blue (MB) solution under sunlight. The effects of various parameters such as initial dye concentration, catalyst dosage and recyclability of the catalyst were evaluated to determine the best conditions. Results obtained suggest that TiO 2 nanoparticles synthesised through the green chemistry approach under optimum conditions exhibited an effective photodegradation process of MB solution under sunlight.

Green synthesis of TiO2 nanoparticles from Syzygium cumini extract for photo-catalytic removal of lead (Pb) in explosive industrial wastewater

“…Extract obtained after heating was filtered using Whatman filter paper and was used as a capping/ stabilizing agent for the synthesis of nanoparticles. TiO 2 NPs by the green route were prepared by adding 80 mL of 5 mM TTIP solution to 80 mL of Syzygium cumini extract in the ratio of 1:1 (volume/volume) followed by continuous stirring at room temperature for 8 h. The mechanism behind the formation of TiO 2 NPs was hydrolysis of TTIP, which was the dominant pathway for the formation of TiO 2 NPs [25]. The leaf extract present in solution mixture act as a capping/stabilizing agent was to prevent agglomeration and achieving the desired shape and size of the TiO 2 NPs.…”

New frontiers in the biosynthesis of metal oxide nanoparticles and their environmental applications: an overview

“…Therefore, the study showed that the photocatalytic activity of TiO 2 NPs has a good repeatability. Recycled TiO 2 NPs for ten times and freshly synthesized TiO 2 NPs analyzed by XRD and FESEM and the porosity, morphological stability of the synthesized TiO 2 NPs remained same as in anatase phase after ten items of washing as worked by Muniandy et al [196]. On the other hand, iron (III) oxide, which is abundant in the Earth crust has been applied as photocatalyst owing to its feasibility of photocatalytic process under visible light.…”

Titanium Dioxide Nanoparticles – Prospects and Applications in Medicine

“…The synthetic methods leading to TiO2 in general as well as to titania NPs include a series of techniques, with sol-gel synthesis and hydrothermal methods being the most frequently applied [26,27], green chemistry and microwave methods being on the rise [28,29]. By careful design and modification of the process parameters (i.e.…”