Photocatalytic and photoelectrocatalytic performance of sonochemically synthesized Cu2O@TiO2 heterojunction nanocomposites

Cu₂O@TiO₂ heterojunction nanocomposites were prepared via ultrasonic method towards the removal of the environmental pollutant of MO by the visible light photocatalytic approach. The structure of prepared Cu₂O@TiO₂ heterojunction nanocomposites was analyzed by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscope, transmission electron microscope, photoluminescence spectroscopy, UV-Visible absorption spectroscopy, diffused reflectance spectroscopy. The photocatalytic degradation ability was tested using methyl orange as a model pollutant. From the observed pseudo-first order reaction, it was clear that Cu₂O@TiO₂ nanocomposites showed enhanced photocatalytic activity (rate = 0.223 s^-1). The formation of demethylated methyl orange as an intermediate was identified from HPLC analysis at a retention time of 3.47 min. When doped with Cu₂O, the TiO₂ preserved the integrity of its structural, revealing the morphology there is no significant changes have been made, favoring photoelectrochemical appliances. In presence of illumination, the photocurrent of Cu₂O@TiO₂ was 4.5 folds greater than that of TiO₂, involving that incorporating with Cu₂O extensively enhanced mobility of electron via reducing the recombination rate of electron-hole pairs.

Sonochemical synthesis of porous NiTiO3 nanorods for photocatalytic degradation of ceftiofur sodium

Porous NiTiO₃ nanorods were synthesized through the sonochemical route followed by calcination at various temperature conditions. Surface morphology of the samples was tuned by varying the heat treatment temperature from 100 to 600°C. The synthesized NiTiO₃ nanorods were characterized by transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray diffraction, diffused reflectance spectroscopy, photoluminescence spectroscopy and Brunauer-Emmett-Teller (BET) analyses. The characterization studies revealed that the NiTiO₃ nanomaterial was tuned to porous and perfectly rod shaped structure during the heat treatment at 600°C. The porous NiTiO₃ nanorods showed visible optical response and thus can be utilized in the photocatalytic degradation of ceftiofur sodium (CFS) under direct sunlight. The photoluminescence intensity of the porous NiTiO₃ nanorods formed while heating at 600°C was lower than that of the as-synthesized NiTiO₃ sample owing to the photogenerated electrons delocalization along the one dimensional nanorods and this delocalization resulted in the reduction of the electron-hole recombination rate. The photocatalytic degradation of ceftiofur sodium (CFS) was carried out using NiTiO₃ nanorods under the direct sunlight irradiation and their intermediate products were analysed through HPLC to deduce the possible degradation mechanism. The porous NiTiO₃ nanorods exhibited an excellent photocatalytic activity towards the CFS degradation and further, the photocatalytic activity was increased by the addition of peroxomonosulfate owing to the simultaneous generation of both OH and SO₄^-.

Chemiluminescence studies between aqueous phase synthesized mercaptosuccinic acid capped cadmium telluride quantum dots and luminol-H2O2

Mercaptosuccinic acid capped Cadmium telluride quantum dots have been successfully synthesized via aqueous phase method. The products were well characterized by a number of analytical techniques, including FT-IR, XRD, HRTEM, and a corrected particle size analysis by the statistical treatment of several AFM measurements. Chemiluminescence experiments were performed to explore the resonance energy transfer between chemiluminescence donor (luminol-H2O2 system) and acceptor CdTe QDs. The combination of such donor and acceptor dramatically reduce the fluorescence while compared to pristine CdTe QDs without any exciting light source, which is due to the occurrence of chemiluminescence resonance energy transfer (CRET) processes.

Sonochemical synthesis of Cu2O nanocubes for enhanced chemiluminescence applications

A facile one-step sonochemical synthesis of Cu2O nanocubes has been developed by ultrasound irradiation of copper sulfate in the presence of polyvinylpyrrolidone and ascorbic acid at pH 11. During sonication, the reaction between acoustic cavitation-generated radicals and CuSO4 produced Cu(OH)2 intermediate which then reacted with ascorbic acid to generate Cu2O nanocubes. The products were characterized by FT-IR, XRD, HRTEM, AFM and particle size analyzer. The prepared Cu2O nanocubes were found to be very effective for enhancing chemiluminescence in the presence of luminol-H2O2 system.