Browsing by Author "Shukla Majhi"

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Barium Titanate Nanocubes as a Dual Electrochemical Sensor for Detection of Dopamine and Acetaminophen
(Institute of Physics, 2022) Mohd Ali; Surbhi Sharma; Renuka Singh; Keshav Sharma; Shukla Majhi; Debanjan Guin; Chandra Shekhar Pati Tripathi
In the present work, we report on the development of a highly sensitive electrochemical sensor for the rapid detection of dopamine, and acetaminophen molecules based on barium titanate nanocubes deposited on a glassy carbon electrode. The as-synthesized barium titanate nanocubes were characterized using X-ray diffraction measurements, field emission scanning electron microscopy, and UV-vis diffuse reflectance spectroscopy. The electrochemical performances of the as synthesised nanomaterials were investigated by cyclic voltammetry and differential pulse voltammetry. A linear response was exhibited by the modified electrode for both dopamine, and acetaminophen in the range 10-100 μM, and the detection limit (S/N=3) was calculated to be 0.35 μM, 0.23 μM respectively. Under the optimised conditions, highly stable, sensitive, selective, and reproducible performances were exhibited by the electrochemical sensor. Furthermore, the as developed sensor also showed acceptable recoveries for the analysis of real samples. © 2022 The Electrochemical Society ("ECS"). Published on behalf of ECS by IOP Publishing Limited.
BSA stabilized copper nanoclusters as a highly sensitive and selective probe for fluorescence sensing of Fe3+ ions
(Elsevier B.V., 2022) Renuka Singh; Shukla Majhi; Keshav Sharma; Mohd Ali; Surbhi Sharma; Deepika Choudhary; Chandra Shekhar Pati Tripathi; Debanjan Guin
We report on the green synthesis of an effective fluorescent based sensor for selective, sensitive and rapid detection of Fe3+ ions using bovine serum albumin (BSA) stabilized copper nanoclusters. The fluorescence intensity of the BSA-CuNCs has been found to be quenched with the addition of Fe3+ ions. An extremely high selectivity and low detection limit of 10 nM (3σ/k) was observed. The sensor was also employed for the sensing of Fe3+ in wastewater and human blood serum samples. The features exhibited by the fluorescent probe suggest its promising applications in the area of analytical and biological field. © 2021 Elsevier B.V.
Development of silver nanoparticles decorated on functional glass slide as highly efficient and recyclable dip catalyst
(John Wiley and Sons Inc, 2020) Shukla Majhi; Keshav Sharma; Renuka Singh; Mohd Ali; Chandra Shekhar Pati Tripathi; Debanjan Guin
The development of a highly reusable and extremely efficient catalyst is still a fundamental as well as technological problem. Here, we report on the preparation and catalytic applications of Silver nanoparticles (AgNPs) immobilized on amine terminated glass slide as a dip catalyst for the transformation of nitro-phenol, intramolecular cascade reaction and synthesis of 5-Phenyl-1H-tetrazole. The dip catalyst system consists of AgNPs stabilized on microscopic glass slide as the support. AgNPs were decorated on the glass slide by modifying the glass surface with (3-Aminopropyl)triethoxysilane (APTES). The dip catalyst was characterized using SEM, EDX, FTIR, and TEM, and AFM. This system is found to be stable in both organic and aquous solvents and exhibits excellent recyclability even at high temperatures. The catalyst was used for 20 cycles of nitrophenol reduction reaction and 5 cycles for other reactions in this study to test its efficiency. No any significant decrease was observed in the activity of the catalyst. We have also investigated the applicability of the AgNPs immobilized on functional glass slide as surface enhanced Raman scattering (SERS) substrate to understand the catalytic reduction reaction mechanism. © 2020 Wiley-VCH GmbH.
Electrochemical Sensing Platform based on Greenly Synthesized Gum Arabic Stabilized Silver Nanoparticles for Hydrogen Peroxide and Glucose
(Institute of Physics, 2022) Keshav Sharma; Shukla Majhi; Chandra Shekhar Pati Tripathi; Debanjan Guin
Gum Arabic stabilized silver nanoparticles (GA-Ag NPs) were successfully synthesized by one step green synthesis method. The as-prepared nanoparticles were characterized using XRD, DLS, FTIR, TEM, and UV-vis spectroscopy. XRD data confirmed that the synthesized Ag NPs were face-centred cubic and the crystallite size was calculated to be around 5 nm. TEM image confirmed the successful synthesis of monodispersed spherical nanoparticles with particle sizes in the range of 10-20 nm. Cyclic voltammetry experiment revealed the outstanding electrochemical response and electrocatalytic behaviour of GA-Ag NPs for the sensing of H2O2. Based on the cyclic voltammetry, amperometric, and differential pulse voltammetric (DPV) experiments, it was concluded that strong oxidizing agent H2O2 undergoes through reduction process at the surface of GA-Ag NPs/GCE. Excellent electrocatalytic behaviour of the GA-Ag NPs was exhibited for sensing of glucose also. The limit of detection as calculated from DPV experiments were 0.242 μM and 0.205 μM for H2O2 and glucose respectively. The reported electrochemical sensor has numerous advantages such as simple and green synthesis method, extremely high sensitivity, stability and reproducibility, and extremely good response. © 2022 The Electrochemical Society ("ECS").
Fabrication of Reduced Graphene Oxide-Silver/Polyvinyl Alcohol Nanocomposite Film for Reduction of 4-Nitrophenol and Methyl Orange Dye
(John Wiley and Sons Inc, 2021) Keshav Sharma; Shukla Majhi; Mohd. Ali; Renuka Singh; Chandra Shekhar Pati Tripathi; Debanjan Guin
The development of ingenious technologies for the purification of wastewater containing highly toxic organic compounds is of high importance in the current research. The application of noble metal nanocatalysts in the presence of sodium borohydride (NaBH4) for the removal of these toxic compounds through chemical reduction method have become an accepted approach in the recent years. The present work reports on the development of a convenient approach to fabricate free standing, robust, and flexible reduced graphene oxide - silver/polyvinyl alcohol (rGO−Ag/PVA) nanocomposite film. The morphological and structural characterizations of the as developed film have been carried out using SEM, TEM, EDAX, Raman, BET, and TGA. The performance of as developed rGO−Ag/PVA nanocomposite film is tested as heterogeneous catalyst in the reduction reaction of 4-Nitrophenol and reduction of Methyl Orange dye. The nanocomposite film-based catalyst exhibited excellent catalytic performances as well as excellent stability in the reduction of toxic organic compounds in wastewater. © 2021 Wiley-VCH GmbH
Facile synthesis of Ag NPs@MgO nanosheets for quantitative SERS-based detection and removal of hazardous organic pollutants
(Elsevier B.V., 2024) Surbhi Sharma; Keshav Sharma; Shukla Majhi; Chandra Shekhar Pati Tripathi; Debanjan Guin
Surface-enhanced Raman spectroscopy (SERS) is a highly precise and non-invasive analytical method known for its ability to detect vibrational signatures of minute analytes with exceptional sensitivity. However, the efficacy of SERS is subject to substrate properties, and current methodologies face challenges in attaining consistent, replicable, and stable substrates to regulate plasma hot spots across a wide spectral range. This study introduces a straightforward and economical approach that incorporates monodispersed silver nanoparticles onto 2-D porous magnesium oxide nanosheets (Ag@MgO-NSs) through an in-situ process. The resulting nanocomposite, Ag@MgO-NSs, demonstrates substantial SERS enhancement owing to its distinctive plasmonic resonance. The effectiveness of this nanocomposite is exemplified by depositing diverse environmental pollutants as analytes, such as antibiotic ciprofloxacin (CIP), organic dyes like rhodamine 6G (R6G) and methylene blue (MB), and nitrogen-rich pollutant like melamine (MLN), onto the proposed substrate. The proposed nanocomposite features a 2-D porous structure, resulting in a larger surface area and consequently providing numerous adsorption sites for analytes. Moreover, engineering the active sites of the nanocomposite results in a higher number of hotspots, leading to an enhanced performance. The nanocomposite outperforms, exhibiting superior detection capabilities for R6G, MB, and MLN at concentrations of 10-6 M and CIP at concentration of 10-5 M, with impressive uniformity, reproducibility, stability, and analytical enhancement factors (EF) of 6.3 x 104, 2 x 104, 2.73 x 104 and 1.8 x 104 respectively. This approach provides a direct and cost-effective method for the detection of a broad spectrum of environmental pollutants and food additives, presenting potential applications across diverse domains. The detected environmental pollutants and food additives are removed through both catalytic degradation (R6G and MB) and adsorption (CIP and MLN). © 2024 Elsevier B.V.
Gum Arabic-mediated synthesis of silver nanoparticles for their applications as colorimetric and SERS-based detection of hydrogen peroxide
(Springer, 2024) Shukla Majhi; Ashish Kumar; Surbhi Sharma; Chandra Shekhar Pati Tripathi; Debanjan Guin
Abstract: We report on the one-step green method to synthesize Gum Arabic stabilized silver nanoparticles (GA-Ag NPs). The synthesized particles are monodispersed and in the size range of 15–20 nm. The synthesized Ag NPs are used as a colorimetric sensor for the detection of H2O2 and glucose with a detection limit of 11.7 nM and 0.13 µM, respectively. The sensor has also been used for the detection of H2O2 in water samples and glucose in human blood serum samples. The GA-Ag NPs decorated on filter paper have also shown excellent SERS activity for the detection of H2O2 with a detection limit of 0.56 µM. Graphical abstract: (Figure presented.) © The Author(s), under exclusive licence to The Japan Society for Analytical Chemistry 2023. Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
In situ synthesis of carbon quantum dots@gum Arabic-silver nanoparticles as a 'turn-off-on' fluorescent sensor for rapid detection of hydrogen peroxide and mercury (ii) ions in aqueous media
(Royal Society of Chemistry, 2024) Shukla Majhi; Renuka Singh; Chandra Shekhar Pati Tripathi; Debanjan Guin
In this paper, we report on the development of an ‘off-on’ fluorescent probe for the detection of hydrogen peroxide (H2O2) and mercury ions (Hg2+) using an in situ synthesized carbon quantum dot and gum Arabic silver nanoparticle composite (CQDs@GA-Ag NPs). Electron microscopy measurement clearly shows that CQDs are attached to the surface of the GA-Ag NPs. The fluorescence intensity of the CQDs was dramatically quenched in the synthesized nanocomposite via the inner filter effect (IFE) mechanism. After adding H2O2 to the nanocomposite system, the Ag NPs got oxidized leading to the formation of Ag+ ions, and the CQDs regained their photoluminescence (PL) property. This facilitates the detection of H2O2 with an extremely low detection limit of 1.02 μM. Furthermore, the as-developed nanocomposite was also tested for the detection of Hg2+ ions, obtaining a remarkably low detection limit of 1.82 μM. The developed probe was extremely selective over a wide range of interfering ions and substances. © 2024 The Royal Society of Chemistry.
Magnetically separable Ag@Fe3O4-GO nanocomposites for SERS detection, removal of organic pollutants and oil from water, and antibacterial applications
(Royal Society of Chemistry, 2024) Keshav Sharma; Shukla Majhi; Renuka Singh; Surbhi Sharma; Priya Dhyani; Chhaya Goyal; Chandra Shekhar Pati Tripathi; Debanjan Guin
A facile wet chemical method was employed to synthesize magnetically separable Ag@Fe3O4-GO nanocomposites (NCs). The synthesized Ag@Fe3O4-GO NCs were characterized by different analytical techniques including X-ray diffraction (XRD), Raman, vibrating sample magnetometer (VSM), Brunauer-Emmett-Teller (BET), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). In the synthesized Ag@Fe3O4-GO NCs, the role of GO is to adsorb organic dyes from wastewater, superparamagnetic Fe3O4 nanoparticles (NPs) assist magnetic separation, and Ag NPs act as a SERS substrate for the detection of organic dyes and as a catalyst to reduce organic pollutants in the presence of a reducing agent (NaBH4). The catalytic efficiency of the synthesized Ag@Fe3O4-GO NCs was evaluated in the reduction of organic pollutants such as methylene blue (MB) in water under mild conditions. These nanocomposites are also efficient for the removal of lubricant oil from water by applying a simple external magnetic field. The composite also displays antibacterial activity towards Gram-positive and Gram-negative bacteria. © 2024 The Royal Society of Chemistry.
Palladium nanoparticles on polydimethylsiloxane film for C−C coupling reactions, and catalytic reduction of organic pollutants in water
(John Wiley and Sons Inc, 2023) Shukla Majhi; Renuka Singh; Keshav Sharma; Chandra Shekhar Pati Tripathi; Debanjan Guin
In this study, we present a novel method for immobilizing Palladium nanoparticles (Pd NPs) onto a polydimethylsiloxane (PDMS) support (Pd NPs@PDMS). To enhance the stability of Pd NPs on the PDMS surface, we functionalized a PDMS thin film with amine groups. The structure and morphology of the resulting Pd NPs@PDMS material were characterized using various techniques, including field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS) measurements. Furthermore, we investigated the catalytic performance of the Pd NPs@PDMS nanocatalyst for the reduction of well-known environmental pollutants, such as 4-nitrophenol (4-NP), 2-nitrophenol (2-NP), 4-nitroaniline (4-NA), Methyl Orange (MO), Methylene Blue (MB), and Congo Red (CR), in the presence of sodium borohydride (NaBH4) at room temperature (RT). Additionally, we explored the application of the prepared nanocatalyst in carbon-carbon (C−C) coupling reactions, specifically Suzuki Miyaura and Sonogashira reactions. The results obtained in this study demonstrated the high efficiency and environmentally friendly nature of Pd NPs@PDMS as a catalyst for both C−C coupling reactions and the degradation of organic pollutants. © 2023 Wiley-VCH GmbH.
Silver nanoparticles decorated on graphene oxide modified polyester fabric: Catalytic reduction of 4-nitrophenol, organic dyes and SERS application
(Elsevier Ltd, 2022) Keshav Sharma; Mohd Ali; Renuka Singh; Shukla Majhi; Surbhi Sharma; Chandra Shekhar Pati Tripathi; Debanjan Guin
We report on the immobilization of silver nanoparticles on functional graphene oxide modified polyester fabric (AgNPs@GO/PET) for catalytic reduction of organic pollutants. In this work, the polyester fabric was modified with hydrophobic graphene nanosheets using a simple dip-coating method. The as prepared hydrophobic inert graphene oxide modified polyester fabric (GO/PET) substrate was used to stabilize oleylamine coated monodispersed silver nanoparticles. The morphology, size, and structure of the catalyst was investigated through X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), dynamic light scattering (DLS), Fourier-transform infrared spectroscopy (FTIR), Thermogravimetric analysis (TGA) and Raman spectroscopy. Outstanding catalytic performance was exhibited by the AgNPs@GO/PET catalyst for the reduction reaction of 4-nitrophenol, methyl orange and methyl red. Surface enhanced Raman scattering (SERS) was also employed for the time dependent monitoring of reduction of 4-Nitrothiophenol. The present work highlights the importance of the as developed catalyst for the catalytic reduction of organic pollutants and SERS sensing with excellent stability and reusability. © 2022 Elsevier Ltd