Cobalt hexacyanoferrate adsorbed on TiO2 nanoparticles and their modified glassy carbon electrodes for electrocatalytic oxidation and amperometric determination of hydrazine.

TiO2 nanoparticles (NPs) were prepared at low temperature by stepwise hydrolysis of TiF4 in aqueous solution at 100 °C. TiO2 NPs were obtained at low temperature as small size particles. Subsequently, cobalt hexacyanoferrate (CoHCF) is adsorbed on the surface of the TiO2 NPs through the ion exchange method. This method is simple and forms TiO2/CoHCF nanocomposite. TiO2 interacts with KCo[Fe(CN)6] which leads to the formation of TiO(OH)-Co bond; this is confirmed by a shift in the XPS analysis. The prepared TiO2/CoHCF nanocomposite has been characterized by FT-IR spectrum, X-ray photoelectron spectra (XPS), scanning electron microscope (SEM), high resolution transmittance electron microscope (HRTEM) and energy dispersive X-ray pattern (EDX). The TiO2/CoHCF nanocomposite is modified by the glassy carbon electrode (GCE) as an excellent electrocatalyst for the oxidation of hydrazine and is also used for the amperometric determination of hydrazine.

Biosynthesis of zerovalent iron nanoparticles for catalytic reduction of 4-nitrophenol and decoloration of textile dyes.

We demonstrate a green chemistry approach to synthesize narrow-sized zerovalent iron (nZVI) nanoparticles using Artocarpus heterophyllus Lam. leaf extract as reducing and capping agent. The produced nZVI was characterized by various instrumental methods including ultraviolet-visible spectra, transmission electron microscopy, vibrating sample magnetometer (VSM), X-ray diffraction, and Fourier transform infrared spectroscopy. Based on the electron microscopy observations, the particle size was estimated to be ∼30 nm. In VSM, the saturation point of magnetization was observed to be 0.6 emu g-1 under a magnetic field of 0 ± 30 kOe. The synthesized nZVI was amorphous in nature as per the XRD results. The catalytic activity of the nZVI was employed for the catalytic reduction of 4-nitrophenol (4-NP) and decoloration of textile dyes such as methylene blue, methyl orange, and malachite green, respectively. The proposed nZVI synthesis method exhibited better catalytic performance toward reduction of 4-NP and degradation of dyes within 4 min for 0.1 mg of catalyst. Moreover, the synthesized catalyst nZVI can be recoverable and reutilized in many cycles without loss of its significant catalytic activity. The synthesized nZVI could be a promising material to treat industrial wastewater via profitable, sustainable, and ecofriendly approaches.

Evaluation of biopolymer-derived carbon dots as cancer diagnostic biomarkers for human monocyte cell lines (THP-1).

Fluorescent carbon dots (C-dots) were fabricated from Anogeissus latifolia (Gum ghatti) gum extract using direct microwave pyrolysis method. The C-dots are fine-tuned concerning three parameters, viz., NaOH addition (presence and absence), microwave power, and irradiation time. C-dots optical properties were investigated through UV-visible (UV-Vis) and fluorescence spectroscopy. Using field emission scanning electron microscope (FESEM), high-resolution transmission electron microscopy (HRTEM), Fourier transform infrared (FT-IR), X-ray diffraction (XRD), and Raman Spectroscopy, physiochemical properties of synthesized C-dots were inspected. The average size of C-dots was estimated to be 4.8 ± 2 nm and is amorphous. These C-dots displayed high solubility in an aqueous medium due to oxygen functionality, and showed good fluorescence stability to high-ionic concentration and varied pH. The fluorescence spectra outcomes specified that C-dots exhibited excitation-dependent emission behavior. Furthermore, the C-dots biological function was tested for cell biocompatibility and bioimaging. The cytotoxicity studies were performed on Vero cell lines and compared with THP-1 human monocyte cell lines at different concentrations. The results revealed good biocompatibility app. 80 and 90% for Vero and THP-1 cell lines even after 24 h incubation with the C-dots. Finally, by employing C-dots as the fluorescent tool, THP-1 cells were imaged successfully via a Confocal Laser Scanning Microscope (CLSM) in a concentration-dependent manner.

Palladium nanoparticle-decorated reduced graphene oxide sheets synthesized using Ficus carica fruit extract: A catalyst for Suzuki cross-coupling reactions.

We present a biogenic method for the synthesis of palladium nanoparticle (PdNP)-modified by reducing graphene oxide sheets (rGO) in a one-pot strategy using Ficus carica fruit juice as the reducing agent. The synthesized material was well characterized by morphological and structural analyses, including, Ultraviolet-Visible spectroscopy (UV-Vis), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and Transmission Electron Microscopy (TEM) and Raman spectroscopy. The results revealed that the PdNP modified GO are spherical in shape and estimated to be a dimension of ~0.16 nm. The PdNP/graphene exhibits a great catalytic activity in Suzuki cross-coupling reactions for the synthesis of biaryl compounds with various substrates under both aqueous and aerobic conditions. The catalyst can be recovered easily and is suitable for repeated use because it retains its original catalytic activity. The PdNP/rGO catalyst synthesized by an eco-friendly protocol was used for the Suzuki coupling reactions. The method offers a mild and effective substitute to the existing methods and may significantly contribute to green chemistry.