Chemistry - Research Publications

Permanent URI for this collectionhttps://kr.cup.edu.in/handle/32116/37

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Author: search.filters.author.Haldar, Krishna KantaSubject: search.filters.subject.Cost effectiveness

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    Synergistic photophysical and electrochemical response of Te @ PANI for energy harvesting
    (Springer, 2023-01-07T00:00:00) Rani, Pinki; Jewariya, Yogesh; Haldar, Krishna Kanta; Biswas, Rathindranath; Alegaonkar, Prashant S.
    Materials with synergistic functionality are of great importance in consumer electronics. We report on the preparation and assessments of Te @ PANI composite for energy conversion and storage application. Initially, (5�15%) Te @ PANI composites were synthesized by the facile, room temperature, time and cost-effective solid-state synthesis technique followed by characterizations using Fourier transform infra-red, UV-Visible, energy dispersive spectroscopic including X-ray diffractometry and field electron scanning microscopy. Te exfoliates polymeric segments of PANI by bonding benzenoid rings through sulphonated impurity sites which have a profound impact on symmetry molecular bond vibrations. Its analysis is presented. In photophysical application, both dark and luminescent I-V measurements have been performed that showed a linear variation with minimum photo-resistance offered by 10% composite and reaching current > 10�mA under 1.5�V biased conditions. In storage response, Te @ PANI supercapacitor devices are dominating in inductive coupling over capacitive coupling by ten times. Corresponding shunt impedance is seen to be favourably lower for 10% composition, and respective charge transfer impedance has also followed identical behaviour over other classes of samples. The quality factor of the device for 10% is found to be almost twelve times better. However, at a low scan rate (10�mV/s), the presence of Te has changed the tendency of ion migration, thereby, reducing the magnitude of ion current by about three times with an increase in Te from 5 to 15%. Thus, fabricated composite demonstrated synergistic aspects of energy. � 2023, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.
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    Coupling Nonstoichiometric Zn0.76Co0.24S with NiCo2S4Composite Nanoflowers for Efficient Synergistic Electrocatalytic Oxygen and Hydrogen Evolution Reactions
    (American Chemical Society, 2022-12-15T00:00:00) Biswas, Rathindranath; Thakur, Pooja; Ahmed, Imtiaz; Rom, Tanmay; Ali, Mir Sahidul; Patil, Ranjit A.; Kumar, Bhupender; Som, Shubham; Chopra, Deepak; Paul, Avijit Kumar; Ma, Yuan-Ron; Haldar, Krishna Kanta
    Transition-metal sulfide-based composite nanomaterials have garnered extensive interest not only for their unique morphological architectures but also for exploring as a noble-metal-free cost-effective, durable, and highly stable catalyst for electrochemical water splitting. In this work, we synthesized in situ nonstoichiometric Zn0.76Co0.24S with NiCo2S4binary composite flowers (Zn0.76Co0.24S/NiCo2S4) in one step by thermal decomposition of Zn2[PDTC]4and Ni[PDTC]2complexes by a solvothermal process in a nonaqueous medium from their molecular precursor, and their potential application in electrochemical oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) was investigated. Field-emission scanning electron microscopy and transmission electron microscopy analyses revealed the flower-shaped morphology of as-synthesized Zn0.76Co0.24S/NiCo2S4. Again, the structural and chemical compositions were confirmed through powder X-ray diffraction and X-ray photoelectron spectroscopy studies, respectively. The as-obtained 3D flower-type Zn0.76Co0.24S/NiCo2S4nanostructure was further subject to electrochemical OER and HER in alkaline and acidic media, respectively. Zn0.76Co0.24S/NiCo2S4showed low overpotential values of 248 mV (Tafel slope, 85 mV dec-1) and 141 mV (Tafel slope, 79 mV dec-1) for OER and HER activities, respectively, due to the synergistic effects of Zn0.76Co0.24S and NiCo2S4. Several long-term stability tests also affirmed that the Zn0.76Co0.24S/NiCo2S4composite nanostructure is a highly stable and efficient electrocatalyst toward OER and HER activities as compared to the recently reported superior bifunctional electrocatalysts as well as state-of-the-art materials. � 2023 American Chemical Society. All rights reserved.