In this article carbon quantum dots (Cdots) were prepared by a facile, green, economical hydrothermal method of the mixed deionized water and lemon juice. Optical and structural properties of the Cdots have been extensively studied by UV–visible and fluorescence spectroscopy, x-ray diffraction (XRD) techniques, and high resolution TEM (HR-TEM). Surface functionality of Cdots has been illustrated by Fourier transform infrared spectroscopy (FTIR). The fabricated Cdots emit bright green light with broad spectrum. The Cdots exhibit captivating sensitivity and selectivity toward Fe3+ with a linear range from 0 to 80 ppm and a detection limit of 38.08 ppm.

In this article, micro-/nano urchin-like VO2 particles were successfully synthesized by hydrothermal method. Vanadium pentoxide (V2O5), oxalic acid (C2H2O4) and sodium dodecyl sulfate (SDS) surfactant were used as reagents for the synthesis of VO2. The article reports on the synthesis procedure of VO2 nanorods and micro-/nano urchin-like VO2 structure and evaluates the methylene blue (MB) adsorption properties. Morphology and particle size of VO2 were observed by FE-SEM. The VO2 formation phase was studied by XRD. Raman spectroscopy was also used for characterizing VO2. Micro-/nano urchin-like VO2 structure shows good MB adsorption properties that have potential applications in dye-contaminated water treatment.

This paper the role of Cu2+ concentrations in luminescence quenching of Eu3+/Cu2+ doped ZrO2 nanoparticles synthesized by co-precipitation method. The synthesized Eu3+/Cu2+ doped ZrO2 nanoparticles was observed to have a sphere morphology with a diameter of ~ 25 nm. The XRD patterns of the nanoparticles revealed the peaks that were to be crystalline tetragonal ZrO2. The addition of Cu2+ to the Eu3+ doped ZrO2 nanoparticles resulted in a significant suppress luminescence in Eu3+/Cu2+ doped ZrO2 nanoparticles, which was attributed to the spectral overlap occurs between Cu2+ absorption and Eu3+ emission (5D0→ 7F2 transition).