Mesoporous titanium dioxide: sonochemical synthesis and application in dye-sensitized solar cells

Abstract

A novel method for shortening the synthesis time of mesoporous TiO 2 to 6 h is reported. Low-angle XRD and TEM showed that mesoporous TiO 2 with short-range ordered structures was synthesized when octadecylamine was used as a structure-directing agent and when Ti(OPr i ) 4 was used as a precursor. The highest surface area (853 m 2 g 21 ) was obtained after extraction with a dilute solution of nitric acid. The material maintained a high surface area (467 m 2 g 21 ) after calcination at 350 ³C, but the short-range ordered structures collapsed. XPS showed the interaction between TiO 2 and octadecylamine, while DSC, TGA, and FT-IR spectra showed the removal of octadecylamine by extraction and calcination. A mechanism for the fast formation of mesoporous TiO 2 is proposed. It is attributed to the formation of mesoporous material at high temperatures formed in the interface between the gas and bulk solutions resulting from ultrasound irradiation. Electrodes made from the mesoporous TiO 2 were tested in a dye-sensitized solar cell. The short-circuit photocurrent, open-circuit photovoltage and ®ll factor increased with an increase in the sintering temperature, having a performance threshold at 450 ³C, showing that the more ordered structures are required for high solar cell conversion ef®ciencies.

Preparation and characterization of nanocrystalline titania powders by sonochemical synthesis

“…However, an additional step, extraction by nitric acid was required to remove amines. The use of acetic acid was related with the emergence of secondary phases and the prepared powder was not crystalline at 100°C in this investigation [28] in contrast to the observations reported in other investigations [23,26,27,30]. The effect of ultrasonic irradiation was not found as significant in terms of crystallite size and surface area.…”

“…The addition of chemical species such as triblock copolymers [27], acetic acid [28] and amines [29,30] was investigated to adjust the pore/phase structure of the powders. However, an additional step, extraction by nitric acid was required to remove amines.…”

Metallic Nanoparticles, Toxicity Issues and Applications in Medicine

“…The authors have studied the effect of two different methodologies on particle morphology where in the first method, octadecylamine was mixed in ethanol and in the second method, octadecylamine was dispersed in a mixture of ethanol and distilled water. Sphericalor globular-shaped particles were obtained as aggregates of small particles when first method was applied whereas irregular inter-grown aggregates of small particles were formed from the application of second method (Wang et al 2001). The synthesis of magnetic manganese dioxide (MnO 2 ) NPs has been investigated by the sonochemical reduction of MnO 4 in water under Ar atmosphere at 20°C (Abulizi et al 2014).…”

A DFT +Ustudy of (Rh, Nb)-codoped rutile TiO2

“…Titanium dioxide (TiO 2 ) is one such promising material that meets the requirements of a good photocatalyst and has therefore attracted wide attention in recent years for use into solar hydrogen production [2,3], water decontamination [4], and solar cells [5]. However, TiO 2 is a wide band gap semiconductor (3.0 eV for rutile and 3.2 eV for anatase).…”