Browsing by Author "Sweta Bhagat"

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Lanthanum-based double perovskite oxides as cobalt-free catalyst for bifunctional application in electrocatalytic oxygen reactions
(Elsevier Ltd, 2024) Divya Pratap Singh; Sanjukta Mukherjee; Sweta Bhagat; Nandita Singh; Monika Singh; Akhilesh Kumar Singh; Ashish Kumar Singh; Uday Pratap Azad; Suryabhan Singh; Lalrintluangi; Ved Prakash Singh
Electrochemical water splitting by use of suitable electrocatalysts is an important process to establish water as sustainable energy material. Similarly, the Oxygen reduction reaction is an important step involved in fuel cells. Hence, suitable catalysts are required for low-cost and high-performance activity towards both processes. In this work, we synthesized Cobalt-free Lanthanum-based double Perovskites oxides La0.5Sr0.5Fe0.8Cu0.2O3 and La0.5Sr0.5Fe0.8Zn0.2O3 by sol-gel method followed by calcination at different temperatures (800 °C, 900 °C and 1000 °C). Prepared double Perovskite oxide materials exhibit bifunctional catalytic activity towards both oxygen evolution reaction and oxygen reduction reaction. Calcination temperatures and composition have a significant impact on catalytic performance because of morphological control along with tuning of surface composition. Powder X-ray diffraction study has been performed to characterize the materials and phases/composition of materials was further analyzed by Rietveld refinement. The morphology of the best catalyst was analyzed by SEM, EDS mapping and XPS analysis. The catalytic performances of the catalysts were examined using electrochemical methods such as linear sweep voltammetry, cyclic voltammetry and electrochemical impedance spectroscopy in 0.1 M KOH solution. Preparation of noble-metal/cobalt-free catalysts is important finding towards establishing water as potential source for hydrogen production. © 2023 Hydrogen Energy Publications LLC
Modulation of catalytic activity of BSCF towards electrochemical oxygen reactions using different synthetic approaches
(Elsevier Ltd, 2024) Sweta Bhagat; Nandita Singh; Monika Singh; Ashish Kumar Singh; Suryabhan Singh; Uday Pratap Azad; Akhilesh Kumar Singh
This study is focused on the synthesis of the perovskite oxide materials, particularly Ba0.5Sr0.5Co0.8Fe0.2O3-δ, using different synthetic approaches (sol-gel and co-precipitation techniques) and different complexing agents and fuels and their applications for electrochemical water splitting and fuel cells. Prepared perovskite oxide materials exhibits dual catalytic behaviour as it shows the catalytic activity toward the oxygen evolution and reduction reactions in alkaline solution. The Ba0.5Sr0.5Co0.8Fe0.2O3-δ electrocatalyst exhibits remarkable efficiency and durability for the OER in basic electrolytes, with a Tafel slope of 70.38 mV/dec for Best catalyst. The best ORR activity observed for Ba0.5Sr0.5Co0.8Fe0.2O3-δ synthesized using citric acid shows Tafel slope of 356.43 mV/dec. These oxide materials also show enhanced efficiency in capacitive applications. Additionally, the prepared perovskite oxide materials have been characterized by Powder X-ray diffraction, Le-Bail refinement, scanning electron microscopy, Energy dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy analysis, and high-resolution Transmission Electron Microscopy. Electrochemical techniques such as linear sweep voltammetry, cyclic voltammetry, and electrochemical impedance spectroscopy techniques were used to assess the catalytic performance of the prepared electrocatalysts in 0.1M KOH solution. © 2024 Hydrogen Energy Publications LLC
Nanotechnology applications in pandemic prediction
(Elsevier, 2025) Nandita Singh; Kalyani Dewangan; Jitendra Sahu; Uday Pratap Azad; Divyanshu Singh; Sweta Bhagat; Ashish Kumar Singh; Suryabhan Singh; Sunil Kumar Singh; Ananya Srivastava; Divya Pratap Singh
The necessity for novel ways utilizing nanotechnology in antiviral tactics is demonstrated by the continuous fight against viral infections, which has been brought to light by the COVID-19 outbreak. With so many potential applications-biosensors, vaccines, disinfectants, and nanoparticles/functionalized nanoparticles have become increasingly attractive tool in the battle against viral epidemics. The function of nanoparticles in pandemic control is assessed in this book chapter, and their possible uses, advantages, and drawbacks are examined. The significance of nanotechnology in managing viral outbreaks, namely in vaccine development, is the first topic we cover. Although the use of metallic nanoparticles to functionalize protective face masks has become popular as a sustainable substitute for throwaway masks, improving virus filtering and cutting down on waste generation, incorrect disposal of these masks might pollute the environment and even cause ecological damage. In our second section, we will discuss various types of nanoparticles or functionalized nanoparticles-based sensors to detect the pandemic associated viruses at very early stage. For this purpose, along with various types of nanoparticle based-sensors, the selection of appropriate electrochemical techniques is also equally important for the better performance of the constructed biosensors. Along with COVID-19 we will discuss other pandemics such as swine flu, HIV/AIDS, and black death. We must reduce such possible dangers and environmental effects in order to properly control outbreaks. For this reason, it is essential to comprehend the benefits and drawbacks of using nanoparticles while creating efficient plans for controlling pandemics moving forward. © 2025 Elsevier Inc. All rights reserved.