Browsing by Author "Shweta Pal"

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Cu-Fe Prussian blue analog nanocube with intrinsic oxidase mimetic behaviour for the non-invasive colorimetric detection of Isoniazid in human urine
(Elsevier Inc., 2021) Ravi Prakash Ojha; Shweta Pal; Rajiv Prakash
Isoniazid (INH) is a crucial antibiotic widely applicable in the chemotherapy of Tuberculosis. Any discrepancy of INH in the blood may be life-threatening and causes neurotoxicity and other health issues. In this work, we present a colorimetric technique for the easy quantification of the INH in human urine. We have synthesized Cu-Fe Prussian blue analogue nanocube (CuFe-PBA-NC) using a simple precipitation method. The synthesized nanocube has been successfully characterized by Fourier transfer infrared spectroscopy (FTIR), X-ray diffraction (XRD), Scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS). The synthesized CuFe-PBA-NC act as an excellent oxidase mimic, having a very high affinity for TMB (3,3′,5,5′-tetramethylbenzidine) furnishing a blue color compound with a characteristic absorbance peak at λmax = 652 nm. Further, we have exploited the oxidase property of CuFe-PBA-NC for the colorimetric detection of the INH in human urine. The developed sensor shows very high sensitivity in the range of 1 to 100 μM with a detection limit of 0.44 μM. Furthermore, a portable kit was developed for the onsite detection of the INH concentrations in the test samples. The method is easy and cost-effective with sensitive detection of INH. © 2021
Engineered Ni–Fe prussian blue analogue nanocubes and their transformation into nanocages and mixed oxide for applications as bifunctional electrocatalyst
(Elsevier Ltd, 2024) Shweta Pal; Subhajit Jana; Devesh Kumar Singh; Vellaichamy Ganesan; Uday Pratap Azad; Rajiv Prakash
3D nanostructured Prussian blue analogues (PBA) are promising candidates in the family of metal-organic frameworks (MOFs) for applications as bifunctional electrocatalysts due to their open framework structures, high specific surface areas and variable metal active sites. Due to their facile synthesis approach and unique framework structures, these nanostructures can be easily transformed into different structures/materials having different compositions. Herein, we have synthesized Ni–Fe Prussian blue analogue nanocubes (NiFe-PBA-NC) via a simple precipitation method and converted them into Ni–Fe Prussian blue analogue nanocages (NiFe-PBA-NG) and porous mixed metal oxide (NiFe-oxide). For the conversion of nanocubes to nanocages a very controlled etching process is carried out by using an ammonia solution while for the formation of porous mixed metal oxide, nanocubes are annealed in the presence of air. The transformation of nanocubes to nanocages and mixed metal-oxide is thoroughly characterized by various spectroscopic and microscopic techniques and employed as a bifunctional electrocatalyst for oxygen evolution and oxygen reduction reactions (OER and ORR, respectively) in which NiFe-oxide proved to be the best bifunctional catalyst. This thorough and systematic study reveals the fundamentals of the structure-property co-relation towards engineering novel bifunctional electrocatalysts. © 2023 Hydrogen Energy Publications LLC