School Of Basic And Applied Sciences

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    Bio-assisted Synthesis of Au/Rh Nanostructure Electrocatalysts for Hydrogen Evolution and Methanol Oxidation Reactions: Composition Matters!
    (American Chemical Society, 2023-08-11T00:00:00) Biswas, Rathindranath; Dastider, Saptarshi Ghosh; Ahmed, Imtiaz; Biswas, Sayani; Mondal, Krishnakanta; Haldar, Krishna Kanta
    In the field of catalysis, bimetallic nanostructures have attracted much interest. Here, we discuss the effect of Au/Rh bimetallic composition-tuned nanostructure and electrocatalytic activity. A simple bio-assisted technique was used to fabricate multiple Au:Rh nanoplate ratios (25:75, 50:50, and 75:25). XRD and XPS studies show that both Au and Rh phases coexist in a bimetallic nanostructure, and electron microscopy confirms the formation of a triangle-shaped nanoplate. Au0.25Rh0.75 exhibited the maximum catalytic activity and good stability for hydrogen evolution reaction (HER) with an overpotential of 105 mV at a current density of 10 mA/cm2. On the other hand, Au0.50Rh0.50 exhibits a higher activity for methanol oxidation reaction (MOR) compared to the other compositions. Theoretical studies indicate that the electrocatalytic enhancement obtained for both HER and MOR relies on electronic modification effects of the surface, with the overall reaction energy profile being optimized due to Au/Rh d-band mixing. � 2023 American Chemical Society.
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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.
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    DNA Origami-Templated Bimetallic Core-Shell Nanostructures for Enhanced Oxygen Evolution Reaction
    (American Chemical Society, 2022-04-15T00:00:00) Kaur, Gagandeep; Biswas, Rathindranath; Haldar, Krishna Kanta; Sen, Tapasi
    Hydrogen generation through electrocatalytic water splitting offers promising technology for sustainable and clean energy production as an alternative to conventional energy sources. The development of highly active electrocatalysts is of immense interest for improving the efficiency of gas evolution, which is strongly hindered due to the sluggish kinetics of oxygen evolution reaction (OER). Herein, we present the design of Ag-coated Au nanostar (core-shell-type Au@Ag nanostar) monomer structures assembled on rectangular DNA origami and study their electrocatalytic activities through OER, which remains unexplored. Our designed DNA origami-templated bimetallic nanostar catalyst showed excellent OER activity and high stability without using any external binder and exhibited a current density of 10 mA cm-2at a low overpotential of 266 mV, which was smaller than those of ss-DNA-functionalized Au@Ag nanostars and DNA origami-templated pure Au nanostars. Our results reveal that DNA origami-assembled core-shell Au@Ag nanostars show better electrocatalytic performance as compared to pure-core Au nanostars immobilized on DNA origami, owing to the presence of a highly conductive Ag layer. Such controlled assembly of bimetallic nanostructures on a DNA origami template can provide additional electrochemical surface area and a higher density of active sites resulting in enhanced electrocatalysis. � 2022 American Chemical Society. All rights reserved.
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    A review on phytotoxicity and defense mechanism of silver nanoparticles (AgNPs) on plants
    (Springer Science and Business Media B.V., 2023-03-16T00:00:00) Kumar, Sumit; Masurkar, Prahlad; Sravani, Bana; Bag, Dipanjali; Sharma, Kamal Ravi; Singh, Prashant; Korra, Tulasi; Meena, Mukesh; Swapnil, Prashant; Rajput, Vishnu D.; Minkina, Tatiana
    Silver nanoparticles (AgNPs) are noteworthy used nanomaterials in a wide array of fields, particularly in the agricultural sector. Plants play a multifarious role in the ecosystem and provide a source of food for mankind. The responsibility of the scientific community is to recognize the deleterious impact of AgNPs (1�100�nm in size) on critical crop growth and development of plants, which is required for the assessment of environmental threats to plant, human, and animal health. The continued use of AgNPs in agriculture areas may have negative effects on plant biochemical and physiological responses. The current context focused mainly on AgNPs uptake, transport, and accumulation on crop plants and summarizes different levels of phytotoxicity of AgNPs on plant functions and focused on mechanisms of phytotoxicity employed by AgNPs. Moreover, some tolerance mechanisms and various survival strategies developed by plants under AgNPs toxicity are discussed. This background provides comprehensive information necessary to facilitate profound understanding of the toxic impacts of AgNPs on crop plants. � 2023, The Author(s), under exclusive licence to Springer Nature B.V.
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    A review on phytotoxicity and defense mechanism of silver nanoparticles (AgNPs) on plants
    (Springer Science and Business Media B.V., 2023-03-16T00:00:00) Kumar, Sumit; Masurkar, Prahlad; Sravani, Bana; Bag, Dipanjali; Sharma, Kamal Ravi; Singh, Prashant; Korra, Tulasi; Meena, Mukesh; Swapnil, Prashant; Rajput, Vishnu D.; Minkina, Tatiana
    Silver nanoparticles (AgNPs) are noteworthy used nanomaterials in a wide array of fields, particularly in the agricultural sector. Plants play a multifarious role in the ecosystem and provide a source of food for mankind. The responsibility of the scientific community is to recognize the deleterious impact of AgNPs (1�100�nm in size) on critical crop growth and development of plants, which is required for the assessment of environmental threats to plant, human, and animal health. The continued use of AgNPs in agriculture areas may have negative effects on plant biochemical and physiological responses. The current context focused mainly on AgNPs uptake, transport, and accumulation on crop plants and summarizes different levels of phytotoxicity of AgNPs on plant functions and focused on mechanisms of phytotoxicity employed by AgNPs. Moreover, some tolerance mechanisms and various survival strategies developed by plants under AgNPs toxicity are discussed. This background provides comprehensive information necessary to facilitate profound understanding of the toxic impacts of AgNPs on crop plants. � 2023, The Author(s), under exclusive licence to Springer Nature B.V.