Photocatalytic properties of TiO2 and TiO2/Pt: A sol-precipitation, sonochemical and hydrothermal approach

Abstract

In this work we prepared TiO2 nano-powders and TiO2/Pt nano-composites via three synthesis methods (sol-precipitation, sonochemical method, hydrothermal method) starting with the same precursors and media. To evaluate and compare the physical properties of the prepared materials, X-ray diffraction analysis, BET measurements, FTIR spectroscopy, X-ray photoelectron spectroscopy (XPS) and electron microscopy (TEM, HRTEM, SAED) were applied. The results showed changes to the TiO2 phase composition and crystallinity, the specific surface area as well as the platinum's particle shape and size, depending on the method of synthesis. To determine the photocatalytic efficiency of the prepared materials, the photocatalytic discoloration of the methylene blue solution was evaluated using UV-Vis spectroscopy. The important properties required for a high photocatalytic activity, related to the surface characteristics and the phase composition, were determined in terms of the synthesis method. It was concluded that the optimum characteristics were obtained when using the hydrothermal approach, where the TiO2 had two phases, i.e., - anatase and rutile, a Pt-phase in the form of nanoparticles and adsorbed Pt-molecular species, as well as the presence of available free surface hydroxyl groups. Such characteristics had a critical influence on the photocatalytic activity of the final material.

Role of Ultrasound in the Synthesis of Nanoparticles and Remediation of Environmental Pollutants

“…Efficiency of the photocatalytic degradation of Cresol Red 77 was 98.7 % in 60 min of duel frequency ultrasound (20/40 kHz) using active carbon fiber loaded Fe 3+ -TiO 2 . However, in a comparative study of photocatalytic activity of TiO 2 and TiO 2 /Pt, synthesized by solprecipitation, sonochemical and hydrothermal methods respectively, the degradation of Methylene Blue was found to be maximum with TiO 2 nano-powder and TiO 2 /Pt nanocomposite, synthesized through hydrothermal method 78 . In another comparative study of the photocatalytic activity of nano-particles, synthesized through ultrasound assisted solgel method (precursor Ti[OC 4 H 9 ] 4 ) on the photodegradation Methyl Orange have been reported.…”

Synthesis of TiO₂ from TiOSO₄ Solution with Sonochemical Method

“…There are several methods in the synthesis of TiO2 particles, including micro-emulsion methods [9], precipitation [10], hydrothermal [11], sol-gel [12][13][14], and sonochemistry [15][16][17][18]. Raw materials for the synthesis of TiO2 include titanium n-butoxide (Ti(OC4H9)4) [10], titanium isopropoxide (TiC12H28O4) (TTIP) [12][13][14]16,19], and titanyl sulfate (TiOSO4) [20][21][22]. The need for a simple, fast and effective process of producing nanometer-sized particles and inexpensive raw materials is important in the future.…”

The Assembly of TiO2 Nanoparticles into Micrometer‐Sized Structures, Photocatalytically Active Under UV and Vis Light

“…The superior photocatalytic activity of the anatase phase arises from the higher surface hydroxylation, the greater capacity to adsorb oxygen, and the better bulk transport of the excitons to the surface . However, there are reports which show that an even higher efficiency can be achieved with biphasic TiO 2 , that is, a mixture of anatase and rutile . This is because in biphasic TiO 2 a band‐gap alignment takes place, which then lowers the effective band gap of the composite material and so facilitates the separation of the charge carriers .…”