Indian Association for the Cultivation of Science

About: Indian Association for the Cultivation of Science is a education organization based out in Kolkata, India. It is known for research contribution in the topics: Excited state & Catalysis. The organization has 3867 authors who have published 10457 publications receiving 220098 citations.

Two-Dimensional Group IV Monochalcogenides: Anode Materials for Li-Ion Batteries

Abstract: The selection of a suitable electrode material is a fundamental step in the development of Li-ion batteries (LIBs) to achieve enhanced performance. In the present study, we have explored the feasibility of monolayers of phosphorene analogues, namely, group IV monochalcogenides (SiS, SiSe, GeS, GeSe, SnS, and SnSe), to serve as anode materials in LIBs by density functional theory (DFT). Our exploratory study indicates that lithium binds efficiently to these monolayers, with Li@SiS and Li@SiSe showing appreciable stability comparable to that of phosphorene. The zero-point-energy-corrected minimum-energy pathway (MEP) for Li diffusion demonstrates high anisotropy for both SiS and SiSe, with a low diffusion barrier of ∼0.15 eV along the zigzag direction. Inclusion of corrections due to quantum effects such as the zero-point energy (ZPE) and quantum mechanical tunneling (QMT) increases the diffusion rates by 6–10% at room temperature and results in increasingly significant contributions as the temperature is r...

Microwave assisted rapid conversion of carbohydrates into 5-hydroxymethylfurfural catalyzed by mesoporous TiO2 nanoparticles

Abstract: Energy efficient and sustainable process for the production of 5-hydroxymethylfurfural (HMF) from carbohydrates is highly demanding. Here, direct conversion of carbohydrates into HMF has been investigated over self-assembled mesoporous TiO2 nanoparticles (NPs) catalyst. Monosachharides d -fructose and d -glucose, disaccharides sucrose, maltose, cellobiose were successfully converted into HMF with variable yields in both aqueous and organic mediums under microwave-assisted heating conditions. The effects of solvent polarity, microwave absorbing ability, catalyst loading, reaction time, and substrate variations on the HMF yields have been studied. Pyridine-IR and NH3-TPD analyses confirmed the presence of Lewis acidic sites, whereas N2 sorption analysis revealed high BET surface area for the self-assembled mesoporous TiO2 nanomaterials synthesized by using sodium salicylate as template. High surface area, Lewis acidity and uniform nanosphere-like particle morphology are responsible for high catalytic activity in the dehydration of carbohydrate substrates over this mesoporous TiO2 nanomaterial, whereas commercially available TiO2 is almost inactive for this dehydration reaction under similar conditions. The higher microwave energy absorbing ability (tan δ) of the DMSO and NMP resulted in higher HMF yield in organic solvents than water. Catalyst life-time analysis suggested that mesoporous TiO2 NPs catalysts can be recycled for four catalytic cycles without appreciable loss of its catalytic activity.

Energy levels and structural properties of compressed hydrogen atom under Debye screening

Abstract: Time dependent variation perturbation calculations have been performed for estimating the transition energies, os- cillator strengths and transition probability values for a few dipole allowed states of compressed hydrogen atom confined in a weakly coupled plasma. The compression is obtained by embedding the atom at the centre of an impenetrable spherical box. The dipole polarizability of the atom is evaluated at each confinement radius with respect to different plasma screening param- eters. The effect of pressure due to spatial confinement on the dipole polarizability and other atomic properties is analyzed. Results obtained are useful for the diagnostic determination of astrophysical and laboratory plasmas and for the calculation of collision rate coefficients needed for computing opacity of stellar envelopes - a quantity of importance in the context of stellar structure and pulsations.

Microbial synthesis of multishaped gold nanostructures.

Abstract: The development of methodologies for the synthesis of nanoparticles of well-defined size and shape is a challenging one and constitutes an important area of research in nanotechnology. This Full Paper describes the controlled synthesis of multishaped gold nanoparticles at room temperature utilizing a simple, green chemical method by the interaction of chloroauric acid (HAuCl4 x 3H20) and cell-free extract of the fungal strain Rhizopus oryzae. The cell-free extract functions as a reducing, shape-directing, as well as stabilizing, agent. Different shapes of gold nanocrystals, for example, triangular, hexagonal, pentagonal, spherical, spheroidal, urchinlike, two-dimensional nanowires, and nanorods, are generated by manipulating key growth parameters, such as gold ion concentration, solution pH, and reaction time. The synthesized nanostructures are characterized by UV/Vis and Fourier-transform infrared spectroscopy, transmission electron microscopy, and energy dispersive X-ray analysis studies. Electron diffraction patterns reveal the crystalline nature of the nanoparticles and a probable mechanism is proposed for the formation of the different structural entities.