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We report on the development of a highly sensitive electrochemical sensor for the rapid detection of dopamine and acetaminophen molecules based on barium titanate nanocubes deposited on a glassy carbon electrode. The as-synthesized barium titanate nanocubes were characterized using X-ray diffraction measurements, field emission scanning electron microscopy, and UV–vis diffuse reflectance spectroscopy. The electrochemical performances of the as synthesised nanomaterials were investigated by cyclic voltammetry differential pulse voltammetry. A linear response was exhibited by the modified electrode for both dopamine, and acetaminophen in the range 10-100 μM, and the detection limit (S/N=3) was calculated to be 0.35 μM, 0.23 μM respectively. Under the optimised conditions, highly stable, sensitive, selective, and reproducible performances were exhibited by the electrochemical sensor. Furthermore, the as developed sensor also showed acceptable recoveries for the analysis of real samples.

High-intensity ultrasonic waves have great potential for the green synthesis of various nanomaterials under mild conditions and offer an excellent alternative for hazardous chemical methods. Herein a facile approach for the eco-friendly synthesis of Au-ZrO2 nanocatalyst with a high catalytic activity using a facile ultrasonic method is presented. Gold (Au) in the nanosize regime was successfully deposited on the surface of solvothermally synthesized monodispersed ZrO2 nanoparticles (ZrO2 NPs) in a very short period of time (5 min) at room temperature. Spherical shape small size Au nanoparticles that are uniformly dispersed on the surface of ZrO2 nanoparticles were obtained. Notably, in the absence of ZrO2 nanoparticles, HAuCl4 could not be reduced, indicating that nano-sized ZrO2 not only acted as support but also helped to reduce the gold precursor at the surface. The as-prepared Au-ZrO2 nanocatalyst was characterized by various techniques. The Au-ZrO2 nanocatalyst served as a highly efficient reducing catalyst for the reduction of 4-nitrophenol. The reaction time decreased with increasing the amount of catalyst.

The development of ingenious technologies for the purification of wastewater containing highly toxic organic compounds is of high importance in the current research. The application of noble metal nanocatalysts in the presence of sodium borohydride (NaBH 4 ) for the removal of these toxic compounds through chemical reduction method have become an accepted approach in the recent years. The present work reports on the development of a convenient approach to fabricate free standing, robust, and flexible reduced graphene oxide -silver/ polyvinyl alcohol (rGOÀ Ag/PVA) nanocomposite film. The morphological and structural characterizations of the as developed film have been carried out using SEM, TEM, EDAX, Raman, BET, and TGA. The performance of as developed rGOÀ Ag/PVA nanocomposite film is tested as heterogeneous catalyst in the reduction reaction of 4-Nitrophenol and reduction of Methyl Orange dye. The nanocomposite filmbased catalyst exhibited excellent catalytic performances as well as excellent stability in the reduction of toxic organic compounds in wastewater.