Browsing by Author "Jha P.K."

Now showing 1 - 7 of 7
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    Advancements in bifunctional catalysts for unitized regenerative fuel cells: exploring polaronic conduction and heterostructure designs
    (Institute of Physics, 2024) Sharma U.; Jha P.K.; Jha P.A.; Singh P.
    This study investigates the development and performance evaluation of a bifunctional catalyst tailored for unitized regenerative fuel cells (URFCs), capable of facilitating both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in fuel cell and electrolyzer modes. The primary challenge addressed is the creation of electrocatalysts exhibiting high activity and corrosion resistance for oxygen reduction and water oxidation at the oxygen electrode. A novel catalyst structure based on La0.5Sr0.5Fe0.5Ti0.5O3(LSFT), i.e. LSFT/ZnO/LSFT with a thickness of ? 2 ? m, is explored within an environmentally friendly medium. This catalyst demonstrates superior performance characteristics, including reduced overpotential in HER and enhanced stability during oxygen/hydrogen evolution processes in neutral medium. This study identifies the formation of interfacial polarons and polaronic charge modulation resulting from the incorporation of ZnO in LSFT, leading to multifunctional OER/HER behavior. Notably, the proposed interfacial small polaron mechanism offers valuable insights into complex interfacial phenomena and holds promise for applications in diverse heterostructures involving layered 2D materials and transition metal oxides. Moreover, the robust LSFT/ZnO/LSFT catalyst exhibits exceptional stability, maintaining for 168 h of oxygen evolution at a constant potential of approximately 1.66 V for a current density of 1 A cm?2 in a neutral medium. These findings mark a significant advancement in URFC technology and present promising avenues for clean energy storage solutions. � 2024 IOP Publishing Ltd.
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    Catalyzing hydrogen production: Exploring plasmonic effects in self-assembled CuO/Cu2O thin films via pulsed laser deposition
    (American Institute of Physics, 2024) Ranjan A.K.; Jha P.K.; Jha P.A.; Singh P.
    Plasmonic catalysis triggers the dissociation of H 2 or adsorbed O 2 (sluggish processes) under continuous wave excitation via plasmon decay. This is coupled to interband or intraband excitation of d-band or sp-band, respectively, to levels above fermi level of metals. Here, we have studied the plasmonic and photocatalytic behavior in an environment friendly medium with AM 1.5 G sunlight of CuO/ Cu 2 O thin films fabricated by pulsed laser deposition technique in vacuum with varying thickness. We have achieved ? 0.59 kmol h ? 1 g ? 1 H 2 production in the CuO/ Cu 2 O film with a thickness of ? 27 nm. The role of plasmons with metal-dielectric and semiconductor-semiconductor interfaces is conducted through both experimental and theoretical approaches. The results suggest that the impact of plasmonic catalysis/synthesis is subject to the dimension, composition, and band alignment of two interface materials. � 2024 Author(s).
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    Electrolytes for electrochemical energy storage supercapacitors
    (Bentham Science Publishers, 2024) Jha P.A.; Jha P.K.; Singh P.
    In this chapter, the types of electrolytes and the alteration in capacitance with pore size, their power density, and energy density along with the interaction of electrolytes with current collectors are discussed. The electrolytes' electrochemical stability broadly estimates the working cell voltage provided that the electrodes are stable under operating cell voltage. The electrolytes are divided into various categories such as liquid electrolyte, solid-state, and redox-active electrolyte. The liquid electrolytes are further categorized into aqueous and non-aqueous electrolytes. The critical performance parameters such as stability, lifetime, operating temperature, operating voltage, etc. are believed to be affected by electrolytes. Moreover, the electrolytes are believed to interact with the current collectors, additives, binders, separators, and electrode material to affect the practical performance of supercapacitors. However, the capacitance of the electrolyte depends upon the ion size and the matching between the electrode pore size and electrolyte ion size. The power density and energy density depend upon the potential window, ionic conductivity, and electrochemical stability along with concentration, respectively. Further, the ionelectrode interaction is supposed to affect the cycle life and power density as well. The thermal stability of electrolytes depends upon their boiling points, freezing points, and salt solubility and the equivalent series resistance depends upon ion conductivity, mobility, and viscosity. � 2024 Bentham Science Publishers. All rights reserved.
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    La0.5Sr0.5Fe0.5Ti0.5O3 as a Bifunctional Catalyst for H2/O2 Fuel Cells: Towards Enhanced Stability and Electroactivity
    (Institute of Physics, 2024) Sharma U.; Jha P.K.; Jha P.A.; Singh P.
    To address the rising demand for H2 for fuel cells, hydrogen is produced through water splitting (electrochemically/photoelectrochemically).Although perovskite-structured materials show promise for the oxygen reduction reaction (ORR), their effectiveness in the oxygen evolution reaction (OER) poses a challenge. Consequently, there�s a growing demand for bifunctional catalysts exhibiting high electroactivity across a broad pH range. One potential candidate for exploration as a negative electrode in batteries and fuel cells is LaFeO3. With co-substitution of Sr and Ti, La0.5Sr0.5Fe0.5Ti0.5O3 (LSFT) is formed and explored as an air electrode. In this study, we systematically assess LSFT as a bifunctional catalyst across a broad pH spectrum of electrolytic solutions. LSFT displays increased current densities in both the OER and hydrogen evolution reaction (HER) domains, alongside improved stability, notably in neutral conditions. Our investigation incorporates Density Functional Theory (DFT) simulations to determine surface binding energies and construct a Pourbaix diagram. The results underscore the robustness of LSFT as a perovskite-based bifunctional catalyst, achieving a cycle stability exceeding 600 cycles and a chronopotentiometric stability of 1500 h with a stable potential of ?2 V at the current density of 150 mA/cm2 in the neutral environment. � 2024 The Electrochemical Society (�ECS�). Published on behalf of ECS by IOP Publishing Limited.
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    Metal-Organic Frameworks (MOFs) based nanomaterials for supercapacitor applications
    (Bentham Science Publishers, 2024) Jha P.K.; Jha P.A.; Singh P.
    In the last two decades, nanomaterials with enhanced active sites and better surface kinetics as compared to their bulk counterpart, have been significantly studied for supercapacitor electrode materials. Contemporarily, Metal-organic frameworks (MOFs) by virtue of versatile structure, charge conduction, high porosity, and redoxactive functionality have also emerged as the most potential materials for nextgeneration energy storage technologies. Despite these excellent features, the bulk phase inorganic-MOFs have some chemical and physical limitations that hinder cell performance and thus novel materials are required. Recently, MOFs-based nanomaterials(nMOF) got due attention leading to the discovery of a variety of properties not observed or relevant in bulk systems, such as well-defined 3D structures, permanent porosity, and accelerated adsorption/desorption kinetics. That's why nMOFs are considered an emerging class of modular nanomaterials. However, understanding of nMOFs is still in its infancy, film uniformity along with the unstable structure in a highly corrosive electrolyte is still a bottleneck problem. In this chapter, the recent developments of pristine MOF and MOF-derived porous nanocomposites for the nextgeneration supercapacitor applications will be discussed. � 2024 Bentham Science Publishers. All rights reserved.
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    Regenerative Agriculture: Translating Science to Action
    (CRC Press, 2024) Rakshit A.; Parihar M.; Meena V.S.; Jha P.K.; Sarkar D.; Abhilash P.C.
    This book aims to focus on the current state of knowledge and scientific advances about the complex and intertwined issues of regenerative farming as a transformative solution for offsetting the disastrous climate effects of burning fossil fuels and impairments of natural resource bases. Regenerative agriculture advocates no-till practices, planting cover crops, integrating livestock and crop production, improving animal welfare practices, improving the social and economic well-being of communities, sequestering carbon, improving soil health, and increasing yields and profit with a positive impact on food access or food safety regardless of farm size. This book examines the innovations that will equip agriculture to cope with the competing challenges of addressing food and nutrition security, improving livelihoods, combatting climate change, and sustainably managing natural resources. The scope of this book extends to agricultural scientists, students, consultants, site owners, industrial stakeholders, regulators, and policymakers. � 2024 selection and editorial matter, Amitava Rakshit, Manoj Parihar, Vijay Singh Meena, Prakash Kumar Jha, Deepranjan Sarkar, and Purushothaman Chirakkuzhyil Abhilash.
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    Underutilized edible fruit species of the Indo-Gangetic Plains: a systematic review for food security and land degradation neutrality
    (Turkiye Klinikleri, 2024) Dinesha S.; Rakesh S.; Sarkar D.; Jha P.K.; Balasani R.; Shikha; Kar S.K.; Seth V.; Rakshit A.; Datta R.; Erci?li S.
    Many underutilized edible fruit species (UEFS) are found in the Indo-Gangetic Plains (IGP), which support food security (FS) for both indigenous people and other dependent communities. Unfortunately, there is little study and fragmented information available about these naturally edible products. The UEFS of the IGP was the subject of a systematic review utilizing the PRISMA protocol, which produced implications for FS and land degradation neutrality (LDN). This review aims to survey, summarize, and annotate the published information about the angiosperms native and naturalized UEFS of IGP to identify and make use of this species, particularly for the sustainable development of this region. A systematic review confirmed that 371 species of UEFS, of which 62 species were threatened and near threatened (TNT)-UEFS. Among the TNT-UEFS, 41 species were threatened, while 21 species were NT. The threatened species were further categorized as per the International Union for Conservation of Nature (IUCN) Red List in the IGP as vulnerable (21 species), endangered (16 species), and critically endangered (four species). This systematic review suggests integration of the native and naturalized UEFS in afforestation and reforestation programs to aid in various ecosystem services. Calamus inermis, Corypha taliera, Licuala peltata, and Saurauia punduana are examples of multipurpose species that require immediate sustainable conservation and cultivation initiatives to save them from extinction in the near future. Multipurpose species such as Aegle marmelos, Buchanania lanzan, Manilkara hexandra, Syzygium cuminii, Tamarindus indica are immensely constructive and climate-smart by surviving in harsh agroclimatic conditions and have great potential for establishment on marginal and wastelands throughout the IGP region. These resilient fruit species enhance biodiversity, ecosystems, and landscapes in addition to providing food for humans. It progressively advances India�s commitment to LDN, combating climate change, and achieving the UN-SDGs, which call for reducing hunger and raising FS by 2030. As a result, the study will offer baseline data for the next investigations and be helpful to policymakers in creating sustainable and scientific policies for the IGP. � T�B?TAK.