National Chemical Laboratory

About: National Chemical Laboratory is a facility organization based out in Pune, Maharashtra, India. It is known for research contribution in the topics: Catalysis & Nanoparticle. The organization has 8891 authors who have published 14837 publications receiving 387600 citations.

A mechanochemically synthesized covalent organic framework as a proton-conducting solid electrolyte

Abstract: Mechanochemistry has become an increasingly important synthetic tool for a waste-free environment. However, the poor quality of the so-derived materials in terms of their crystallinity and porosity has been their major drawback for any practical applications. In this report, we have for the first time successfully leveraged such characteristics to show that the mechanochemically synthesized bipyridine based covalent organic framework (COF) outperforms its conventional solvothermal counterpart as an efficient solid-state electrolyte in PEM fuel cells. Marking the first such attempt in COFs, a Membrane Electrode Assembly (MEA) fabricated using the mechanochemically synthesized COF was observed to inhibit the fuel crossover and build up a stable Open Circuit Voltage (OCV = 0.93 V at 50 °C), thereby establishing itself as an effective solid electrolyte material (with a proton conductivity of 1.4 × 10−2 S cm−1), while the solvothermally synthesized COF proved ineffective under similar conditions.

Photocatalytic Metal–Organic Framework from CdS Quantum Dot Incubated Luminescent Metallohydrogel

Abstract: Cadmium sulfide (CdS) quantum dots (<10 nm in size) have been successfully synthesized in situ without any capping agent in a Zn(II)-based low-molecular-weight metallohydrogel (ZAVA). Pristine ZAVA hydrogel shows blue luminescence, but the emission can be tuned upon encapsulation of the CdS quantum dots. Time-dependent tunable emission (white to yellow to orange) of the CdS incubated gel (CdS@ZAVA gel) can be attributed to sluggish growth of the quantum dots inside the gel matrix. Once CdS quantum dots are entrapped, their augmentation can be stopped by converting the gel into xerogel, wherein the quantum dots remains embedded in the solid xerogel matrix. Similar size stabilization of CdS quantum dots can be achieved by means of a unique room-temperature conversion of the CdS incubated ZAVA gel to CdS incubated MOF (CdS@ZAVCl) crystals. This in turn arrests the tunability in emission owing to the restriction in the growth of CdS quantum dots inside xerogel and MOF. These CdS embedded MOFs have been utiliz...

Room-temperature biosynthesis of ferroelectric barium titanate nanoparticles

Abstract: The syntheses of inorganic materials by biological systems is characterized by processes that occur close to ambient temperatures, pressures, and neutral pH, as is exemplified by biosilicification and biomineralization processes in nature. Conversely, laboratory-based syntheses of oxide materials often require extremes of temperature and pressure. We have shown here the extracellular, room-temperature biosynthesis of 4-5 nm ternary oxide nanoparticles such as barium titanate (BT) using a fungus-mediated approach. The tetragonality as well as a lowered Curie transition temperature in sub-10 nm particles was established, and the ferroelectricity in these particles was shown using Kelvin probe microscopy.

Humidity Sensing and Photodetection Behavior of Electrochemically Exfoliated Atomically Thin-Layered Black Phosphorus Nanosheets.

Abstract: Recent investigations on two-dimensional black phosphorus material mainly highlight work on few atomic layers and multilayers. It is still unknown if the black phosphorus atomically thin sheet is an ideal structure for the enhanced gas–solid interactions due to its large surface area. To further investigate this concern, we have synthesized few atomic layer thick nanosheets of black phosphorus using an electrochemical exfoliation method. The surface morphology and thickness of the nanosheet were identified using AFM, TEM, and Raman spectroscopy. The black phosphorus nanosheet thick film device was used for the gas sensing application with exposure to different humidites. Further, the few layer black phosphorus nanosheet based transistor shows good mobility and on/off ratio. The UV light irradiation on the black phosphorus nanosheet shows good response time. The overall results show that the few layer thick film of black phosphorus nanosheets sample exhibits creditable sensitivity and better recovery time ...

Ionic Liquid-Promoted Regiospecific Friedlander Annulation: Novel Synthesis of Quinolines and Fused Polycyclic Quinolines

Abstract: Several room-temperature ionic liquids (ILs) based on 1-butylimidazolium salts with varying anions were synthesized and evaluated for the preparation of biologically active substituted quinolines and fused polycyclic quinolines using the Friedlander heteroannulation reaction. On screening, 1-butylimidazolium tetrafluoroborate [Hbim]BF4 was found to be the best ionic liquid for the heteroannulation reaction, and the reasons to this effect are well explained. The reactions proceed very well under relatively mild conditions without any added catalyst. The IL acts as a promoter for this regiospecific synthesis and can be recycled. By this green approach, various quinolines were prepared in excellent yields and purity and well-characterized.