In the present work, the catalytic potential of natural organocatalyst thiamine hydrochloride is explored for the synthesis of 1,2,4‐triazolidine‐3‐thiones in aqueous medium. The reaction of thiosemicarbazides with various substrates viz aryl/ heteroaryl aldehydes, isatins, cyclic and aromatic ketones to obtain corresponding 1,2,4‐triazolidine‐3‐thiones have been successfully demonstrated for the first time. The method proposed in this work addresses the green chemistry principles such as biodegradable catalyst, ambient reaction condition, shorter reaction time, high yield of the products, recyclability of catalyst and high atom economy.

ZnO has large exciton binding energy (60 meV) and wide direct band gap (3.37 eV). It is a promising base materials for optoelectronics applications. To optimize its optical properties, Cu doped ZnO is synthesized by low cost sol–gel method and analyzed by X‐ray diffraction (XRD), scanning electron microscopy (SEM), and UV–vis spectroscopy. The XRD analysis reveals that the samples are polycrystalline with hexagonal wurtzite structure. It also indicates that there is no impurity peaks present in prepared samples and shows that the samples are stoichiometric. SEM images of Cu doping exhibit a slight variation in grain size. In addition, the absorption spectrum of pure and Cu doped ZnO nanoparticles (NPs) are studied and Tauc plots show band gap narrowing effect on Cu doping concentration to use it as advance material in diiferent devices.

In the present paper, the modified properties of widely used TiO2 material by forming its Ag‐doped TiO2/rGO nanocomposite are studied. The structural investigation by X‐ray diffraction (XRD) reveals the formation of single anatase phase that do not altere even in composite with a decrement in crystallite size from 12 to 8 nm. The SEM micrographs confirm nanosheets formation of rGO while uniform grain shapes of TiO2 nanoparticles (NPs). Fourier transformed infrared spectroscopy (FTIR) remarkably deduce the specific bands to support individual characteristics. However, UV‐vis spectroscopy exposes absorption shift toward the visible side by the effect of silver doping and rGO nanocomposite formation. Similarly, the energy band gap calculation by Tauc plots reveals a reduction in band gap from 3.26 to 3.18 eV. So, these successfully tuned properties of TiO2 open the new path to utilize it in various forthcoming optoelectronic devices.