Browsing by Author "Chandra Shekhar Pati Tripathi"

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2-Dimensional Magnesium Oxide/Polyaniline Nanocomposite Modified Glassy Carbon Electrode for Electrochemical Detection of Dopamine and 4-Nitrophenol
(John Wiley and Sons Inc, 2024) Ashish Kumar; Surbhi Sharma; Chandra Shekhar Pati Tripathi; Debanjan Guin
In this study, we have developed an electrochemical sensor based on a polyaniline (PANI) integrated magnesium oxide nanosheet (MgO-NSs) modified glassy carbon electrode (GCE) for the rapid electrochemical detection of dopamine (DA) and 4-nitrophenol (4-NP). 2-D MgO-NSs were synthesized using a straightforward one-step sugar-blowing method, and PANI was synthesized by the oxidative polymerization of aniline. The nanocomposite (PANI-MgO) was prepared by simple mechanical blending of MgO-NSs with PANI. The as-synthesized nanocomposites were characterized using several analytical techniques to determine their morphological and microstructural properties. The as-synthesized PANI, MgO, and PANI-MgO were further electrochemically characterized using Cyclic Voltammetry (CV) and Electrochemical Impedance Spectroscopy (EIS) techniques. The fabricated PANI-MgO/GCE showed a considerable increase in the redox peak currents of DA and 4-NP, suggesting that PANI-MgO/GCE substantially enhances the electrocatalytic oxidation of DA and the reduction of 4-NP. The analytical performance of PANI-MgO/GCE for the detection of DA and 4-NP was investigated using Differential Pulse Voltammetry (DPV). The developed sensor was successfully applied for the detection of DA and 4-NP in real samples with good recovery results. © 2024 Wiley-VCH GmbH.
A highly responsive UV photodetector based on WO3–ZnO layered thin film
(Elsevier B.V., 2025) Richa Kumari; A. Sameer Ruban Kumar; Sandeep Dahiya; Sanjay Kumar Srivastava; Debanjan Guin; Chandra Shekhar Pati Tripathi
This work focuses on the development of a heterostructure ultraviolet photodetector constructed using tungsten oxide (WO3) nanosheets (NSs) and zinc oxide (ZnO) nanoparticles (NPs), fabricated on Si/SiO2 substrates. For synthesis, a simple, economically feasible hydrothermal for WO3 and sol-gel synthesis approach for ZnO was used. The WO3 NSs/ZnO NPs heterostructure thin-film UV photodetector demonstrates excellent performance, including high responsivity (R), and detectivity (D) of 97.55 A/W, and 6.5 × 1011 Jones, respectively, when exposed to UV light (λ ∼ 365 nm). The working mechanism of the fabricated photodetector explained using a suitable energy band diagram. The WO3 NSs/ZnO NPs heterostructure thin-film UV photodetector exhibits a satisfactory response time, with a rise time of 5.35 s and a fall time of 10.24 s. © 2025 Elsevier B.V.
Bandgap Modulation of Hydrothermally Synthesized CZTS Nanoparticles through Ni Incorporation
(Springer, 2025) Yogesh Kumar Saini; Sanju Mahich; Shubham Gupta; Rishabh Kumar; Chandra Shekhar Pati Tripathi; Anuj Kumar; Sarita Kumari; Sanjay Kumar Swami; Amanpal K. Singh
Kesterite (Cu2ZnSnS4) has gained significant attention in optoelectronic materials research for future solar energy applications due to its composition of earth-abundant elements, nontoxic nature, and cost-effectiveness as a p-type semiconductor material. This study investigates the effect of Ni doping on Cu2Zn1−xSnS4Nix nanoparticles (NPs) synthesized via the hydrothermal method, with varying Ni concentrations (x = 0, 0.005, 0.01, 0.05, 0.1). x-ray diffraction (XRD) and Raman spectroscopy confirm the retention of the kesterite structure with high crystallinity, while x-ray photoelectron spectroscopy (XPS) verifies the incorporation of Ni2+ ions into the Cu2ZnSnS4 (CZTS) lattice. The oxidation states of the Ni+2 metal dopants are clear from the XPS analysis. Field-emission scanning electron microscopy (FESEM) and energy-dispersive x-ray (EDX) analysis reveal changes in particle morphology and elemental distribution due to Ni doping, with FESEM images showing that the particle size of CZTS NPs ranges from 100 nm to 150 nm as the Ni concentration increases. High-resolution transmission electron microscopy (HRTEM) shows clear lattice fringes of both pristine and Ni-doped samples, confirming the crystallinity and highlighting minor distortions in the lattice due to Ni incorporation, which introduces lattice strain. Ultraviolet–visible–near-infrared (UV-Vis-NIR) spectroscopy shows a significant reduction in the optical bandgap from 1.50 eV for pristine CZTS to 1.38 eV for Ni-doped samples, highlighting the importance of bandgap tailoring to optimize CZTS NPs for enhanced solar energy absorption. © The Minerals, Metals & Materials Society 2025.
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.
BaTiO3-MoS2 Nanocomposite as a New Peroxidase Mimic for the Colorimetric and Smartphone-Assisted Detection of H2O2
(Springer, 2024) Mohd Ali; Renuka Singh; Debanjan Guin; Chandra Shekhar Pati Tripathi
Detecting and monitoring hydrogen peroxide (H2O2) levels is crucial across various industries due to its potential health hazards at elevated concentrations. Hence, there’s an urgent need for cost-effective, rapid, and straightforward analytical methods for H2O2 detection and monitoring. This study introduces a simple synthesis method for Barium Titanate (BaTiO3) and Molybdenum disulfide (MoS2) (BaTiO3/MS) nanocomposite via mechanochemical means. The nanocomposite exhibits remarkable peroxidase-like activity, catalyzing the oxidation of TMB (3,3’,5,5’-tetramethylbenzidine) in the presence of H2O2. This catalytic reaction results in the formation of a blue-colored solution with an absorbance peak at 652 nm. The increase in absorbance, facilitated by the catalytic properties of BaTiO3/MS enables precise detection of H2O2 with a detection limit of 8.0 µM. Furthermore, a modified filter paper incorporating the nanocomposite and agarose gel with TMB was developed. The change in color intensity of the filter paper upon exposure to H2O2 was observed and quantified in terms of RGB (Red Green Blue) values using an Android smartphone-based software Color Meter as well as Windows-based software ImageJ. Both the programs gave nearly similar RGB values. This paper-based sensor eliminates the reliance on a UV-visible spectrophotometer, making it portable and user-friendly. This study presents a novel approach for optical and colorimetric detection, with the potential to advance sensing devices for various analytes. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2024.
BaTiO3/rGO nanocomposite modified glassy carbon electrode for electrochemical sensing of 4‑nitrophenol and dopamine in real samples
(Springer Science and Business Media B.V., 2024) Mohd Ali; Keshav Sharma; Debanjan Guin; Chandra Shekhar Pati Tripathi
Here we report a novel electrochemical sensor based on Barium titanate / reduced graphene oxide nanocomposite (BaTiO3/rGO) for precise detection of 4-nitrophenol and Dopamine. The electrochemical characteristics of both analytes were studied using a glassy carbon electrode (GCE) modified with a BaTiO3/rGO composite film. Incorporating reduced graphene oxide (rGO) sheets with BaTiO3 nanoparticles notably improved the electrochemical reactivity of these analytes. The modified electrochemical sensor exhibits a wide linear detection range of 5 to 50 µM for 4-nitrophenol, with a remarkably low detection limit of 0.44 µM. Similarly, dopamine detection demonstrates consistent linearity spanning from 2.5 to 50 µM, with an impressive detection limit of 0.08 µM. Real-world assessments using tap water and human urine samples underscore the exceptional recovery results, highlighting its practical utility. Graphical abstract: (Figure presented.) © The Author(s), under exclusive licence to Springer Nature B.V. 2023.
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.
CeO2 Nanocubes as an Electrochemical Sensing Platform for Simultaneous Detection of Dopamine and Acetaminophen
(Institute of Physics, 2025) Ashish Kumar; Mohd Ali; Amit Pathak; Debanjan Guin; Chandra Shekhar Pati Tripathi
The overlapping redox potentials of analytes and the lack of selectivity present significant challenges for unmodified electrodes in electrochemical sensing. In this work, we have fabricated an electrochemical sensor based on cerium oxide nanocubes (CeO2-NCs) coated glassy carbon electrode (CeO2-NCs@GCE) for individual and simultaneous detection of dopamine (DA) and acetaminophen (APAP) with high sensitivity and selectivity. The CeO2-NCs were synthesized using a one-step hydrothermal method and characterized by Transmission electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, and Raman spectroscopy. Cyclic voltammetry and electrochemical impedance spectroscopy were employed for electrochemical characterizations. With improved electrocatalytic redox activity due to enhanced active surface area and reduced interfacial charge transfer resistance, CeO2-NCs@GCE shows superior detection efficiency. The detection of DA and APAP was evaluated using differential pulse voltammetry. Low detection limit values of 0.696 μM for DA and 0.341 μM for APAP with a wide linear range of 10-400 μM applicability were achieved. The CeO2-NCs@GCE sensor was also used to detect DA in DA injection and APAP in paracetamol tablet samples. The developed sensor demonstrated satisfactory recovery results ranging from 96.5 to 102.8% in pharmaceutical samples, confirming the applicability of the proposed method for simultaneous detection of DA and APAP in real samples. © 2025 The Electrochemical Society (“ECS”). Published on behalf of ECS by IOP Publishing Limited. All rights, including for text and data mining, AI training, and similar technologies, are reserved.
CeO2 nanosheets with prominent peroxidase-mimicking activity for the colorimetric sensing of H2O2, glucose, and ascorbic acid
(Elsevier B.V., 2025) Ashish Kumar; Renuka Singh; Amit Pathak; Debanjan Guin; Chandra Shekhar Pati Tripathi
The peroxidase-mimicking activity of nanozymes has been extensively utilized in the colorimetric turn-on detection of hydrogen peroxide (H2O2) and compounds that produce H2O2 as an intermediate, facilitating the identification of small biological molecules through oxidative chromogenic reactions. In this report, the peroxidase-mimic activity of Cerium Oxide nanosheets (CeO2 NSs) as a nanozyme has been thoroughly investigated. CeO2 NSs were synthesized using a simple, cost-effective one-step sugar-blowing method and characterized by various analytical techniques. CeO2 NSs catalyze to oxidize the peroxidase substrate 3,3′,5,5′-tetramethylbenzidine (TMB) into Ox-TMB in the presence of H2O2, producing a blue color (turn-on). The CeO2 NSs-based colorimetric assay was successfully used to detect H2O2 and glucose. The linear detection ranges for turn-on sensing were found to be 11 µM–455 µM for H2O2, and 5.43 µM–86.95 µM and 86.95 µM–347.82 µM for glucose. The limits of detection (LOD) were calculated as 1.613 μM for H2O2 and 1.068 μM for glucose. Blue-colored Ox-TMB turns colorless with the addition of ascorbic acid; using this colorimetric turn-off mechanism, CeO2 NSs were also able to detect ascorbic acid within the range of 2.2–21.73 μM, with a LOD of 0.058 μM. Satisfactory recovery rates were observed in fruit samples, showing the effectiveness of the sensor in practical applications. © 2025 The Authors
Characterization and potential novel applications of zinc-based traditional medicine, Yashad Bhasma
(Elsevier B.V., 2025) Guruprasad C. Nille; Monisha Bhuyan; Laxmi Narayan Gupta; Mohd Ali; Chandra Shekhar Pati Tripathi; Omkar S. Nille; Shardendu K. Mishra; Anuja A. Vibhute; Pranoti Anil Kamble; Himanshu Ranjan; Amaresh Kumar Singh; Arpita P-Tiwari; Anand Kumar Chaudhary
Background: Yashad Bhasma (YB), the incinerated metal ash of zinc, has been used for centuries in Ayurveda to address a variety of conditions, including eye diseases, diabetes mellitus, anemia, respiratory illnesses, etc. Objective: This research aimed to synthesize and characterize YB and to evaluate its potential antimicrobial, antioxidant, and anti-angiogenic activities. Materials and methods: In this study, YB is synthesized by optimizing the traditional method. Morphological and physicochemical characterization are performed using XRD, XPS, SEM, TEM, EDAX, DLS, TGA-DSC, and FTIR. The antimicrobial activity of YB is assessed using the well diffusion technique against the gram-positive bacterium Staphylococcus aureus (S. aureus) and the gram-negative bacterium Escherichia coli (E. coli). The antioxidant potential is evaluated using the 1,1-Diphenyl-2-Picrylhydrazyl (DPPH) radical scavenging assay and Nitric oxide (NO) radical scavenging assay. A chick chorioallantoic membrane (CAM) assay is performed on fertilized chick eggs to study the anti-angiogenesis potential of YB. Results: The XRD patterns of YB showed the presence of cubic and hexagonal phases of ZnS having average crystallite size of 32.66 nm. XPS data supports the formation of ZnS phase of YB. SEM and TEM data confirmed the size of YB NPs in a range of 250–350 nm. The EDAX analysis confirmed the presence of Zn (37.2 %) and S (21.18 %). The mean particle diameter was 361 nm in DLS. TGA-DSC findings verified that the synthesized material is stable up to 435.80 °C. The FTIR confirms the presence of organic moieties in YB along with ZnS phase. YB effectively inhibited the growth of S. aureus and E. coli. The ability of YB to scavenge DPPH and NO radicals is found to be concentration dependent (50–250 μg/mL). The study also demonstrated that YB has notable antioxidant activity. The disappearance of blood vessels beneath the sample-loaded disk after 7 days indicated the effective anti-angiogenic properties of YB. Conclusion: Altogether, YB exhibited significant antimicrobial, noteworthy antioxidant, and anti-angiogenic activities, indicating its potential as a promising therapeutic agent. © 2025 The Authors
Characterizations of nanoscale two-dimensional materials and heterostructures
(Elsevier, 2020) Anchal Srivastava; Chandra Shekhar Pati Tripathi; Vijay Kumar Singh; Rohit Ranjan Srivastava; Sumit Kumar Pandey; Suyash Rai; Ravi Dutt; Amit Kumar Patel
In recent years, two-dimensional (2D) atomically thin crystals ranging from insulator to superconductor such as graphene, hexagonal boron nitride (h-BN), transition metal dichalcogenides (TMDs), etc. have attracted extensive attention due to their exceptional properties and many potential applications in various areas. In this chapter we focus on the experimental characterization of 2D materials and their heterostructures andcover brief introduction and detailed structural, optical, and chemical characterizations of some important 2D materials. © 2020 Elsevier Inc.
Copper oxide nanosheets as an effective nanozyme with haloperoxidase-like activity for the colorimetric detection of H2O2 and glucose
(Elsevier B.V., 2024) Renuka Singh; Richa Kumari; Chandra Shekhar Pati Tripathi; Debanjan Guin
Copper oxide nanosheets (CuO NSs) have been successfully obtained by exploiting an effective one-step approach of sugar-blowing method followed by calcination. The nanosheets were characterized by several techniques like X-ray powder diffraction (XRD), Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR). Impressively, CuO NSs display haloperoxidase (HPO) like catalytic activity which catalyses the oxidation of chloride ions by H2O2 giving rise to reactive chlorine species (RCS). A sensitive and selective colorimetric sensor was then demonstrated via the oxidation of chromogenic substrate 3,3′,5,5′- tetramethylbenzidine (TMB) by the novel nanoenzyme CuO NSs through the generation of RCS for H2O2 and glucose detection with limit of detection of 109 nM and 21 nM in the linear ranges of 4.6 µM to 769 µM and 0.22 µM to 19.57 µM respectively. Additionally, the methodology is validated for the analysis of glucose in real samples. © 2024 Elsevier B.V.
Covalent functionalization of graphene oxide with l-lysine for highly sensitive and selective simultaneous electrochemical detection of rifampicin and acetaminophen
(Springer Science and Business Media B.V., 2024) Keshav Sharma; Ashish Kumar; Surbhi Sharma; Chandra Shekhar Pati Tripathi; Debanjan Guin
In the present work, graphene oxide covalently functionalized with l-lysine (LSN@GO)-based electrochemical sensor has been developed for the ultrasensitive individual as well as the first ever simultaneous detection of Rifampicin (RIFA) and Acetaminophen (APAP) drugs. The synthesized LSN@GO composite, as well as its precursors LSN and GO, were characterized using FT-IR, XRD, TGA, XPS, SEM and EDAX. The electrochemical studies were performed using Cyclic Voltammetry (CV), Linear Sweep Voltammetry (LSV), and Electrochemical Impedance Spectroscopy (EIS). The fabricated LSN@GO/GCE electro-sensor’s interface exhibited efficient electrical activity for the analysis of RIFA and APAP under the optimized conditions, owing to its substantial electrochemically active surface area and exceptional electron transport capabilities. The detection of RIFA and APAP in various pH environments entailed a proton-dependent mechanistic approach. The sensor displayed a robust linear correlation over a broad range (0.5 to 10 µM) for both RIFA and APAP, with low detection limits of 4.3 nM for RIFA and 5.8 nM for APAP (S/N = 3), along with quantification limits of 14.6 nM for RIFA and 19.4 nM for APAP (S/N = 10) for their individual detection. For simultaneous detection, the detection limit of 4.2 nM for RIFA and 6.0 nM for APAP were observed. We successfully detected spiked RIFA and APAP in real drug and urine samples without pre-treatment, demonstrating significant detection limits and no notable interference from excipients with satisfactory recovery data. The developed sensing platform demonstrated exceptional electrochemical performance for the detection of RIFA and APAP, showcasing significant potential for applications in clinical diagnosis and pharmaceuticals. Graphical abstract: (Figure presented.) © The Author(s), under exclusive licence to Springer Nature B.V. 2023.
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.
Effect of dissolved salt on the anomalies of water at negative pressure
(American Institute of Physics Inc., 2020) Alberto Zaragoza; Chandra Shekhar Pati Tripathi; Miguel A. Gonzalez; José Luis F. Abascal; Frédéric Caupin; Chantal Valeriani
Adding salt to water at ambient pressure affects its thermodynamic properties. At low salt concentration, anomalies such as the density maximum are shifted to lower temperature, while at large enough salt concentration, they cannot be observed any more. Here, we investigate the effect of salt on an anomaly recently observed in pure water at negative pressure: the existence of a sound velocity minimum along isochores. We compare experiments and simulations for an aqueous solution of sodium chloride with molality around 1.2 mol kg-1, reaching pressures beyond -100 MPa. We also discuss the origin of the minima in the sound velocity and emphasize the importance of the relative position of the temperatures of sound velocity and density anomalies. © 2020 Author(s).
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").
Enhanced photocatalytic degradation of Rhodamine B using gold nanoparticles decorated on BaTiO3 with surface plasmon resonance enhancement
(Springer, 2024) Mohd Ali; Payal Swami; Ashish Kumar; Debanjan Guin; Chandra Shekhar Pati Tripathi
This study focused on synthesizing and applying gold nanoparticle (Au NP) decorated barium titanate (BaTiO3) nanoparticles for photocatalytic purposes. BaTiO3 NPs were synthesized using a facile hydrothermal method. Various techniques were employed to characterize the structure and morphological characteristics of the prepared materials. The photocatalytic degradation of Rhodamine B over the Au NPs-modified BaTiO3 photocatalysts was studied. Trapping experiments were conducted using different scavengers to elucidate the degradation mechanism and the involvement of photogenerated species. The incorporation of an appropriate amount of Au NPs into the composites resulted in a significant improvement in photocatalytic activity, attributed to the combined effect of Schottky junction at the interface and the surface plasmon resonance of Au NPs. Graphical abstract: (Figure presented.) © The Author(s), under exclusive licence to The Japan Society for Analytical Chemistry 2024.
Enhanced piezocatalytic degradation of mixed organic dyes using BaTiO3–MoS2 heterostructure nanocomposites: A mechanistic investigation
(Elsevier Ltd, 2024) Mohd Ali; Renuka Singh; Richa Kumari; Debanjan Guin; Chandra Shekhar Pati Tripathi
Piezocatalysis garners significant interest as a potential solution to environmental issues, specifically regarding dye pollutants. Nonetheless, the main obstacle in the piezoelectric efficiency of materials for eliminating organic pollutants from water has been the recombination of charge carriers. Here we report on the fabrication of a piezoelectric nanocomposite of BaTiO3 (BT) Nanoparticles and MoS2 (MS) Nanosheets for the enhanced piezocatalytic degradation of dye pollutants. The sample with 1.0 wt % MoS2 content (BT/MS1) demonstrates greater efficacy compared to both 2.0 wt % MoS2 (BT/MS2) and BaTiO3 (BT) alone in degrading Rhodamine B (Rh B) and Methyl Orange (MO). Specifically, BT/MS1 exhibits 1.84- and 2.8-times enhanced performance for Rh B and MO degradation respectively, in comparison to BT alone. It is demonstrated that the charge transfer system at the interface of BT and MS effectively lowers the recombination of electron-hole (e‒- h+) pairs, generated during piezocatalysis thereby enhancing the degradation. The composite sample was further used for the successful degradation of a mixture of dyes. This study introduces a novel approach to enhance catalysis by hybrid composite in piezoelectric materials. © 2024 Elsevier Ltd
Enhanced sensitivity of surface plasmon resonance biosensor for the selective detection of immunoglobin (IgG)
(Springer, 2022) Awadhesh Kumar; Sarvesh K. Dubey; Anil Kumar; Chandra Shekhar Pati Tripathi; S.K. Srivastava
In this work, we propose a surface plasmon resonance (SPR) biosensor based on a hybrid structure of silicon nitride (Si3N4), molybdenum trioxide (MoO3), and graphene oxide (GO) in the Kretschmann configuration. To investigate the performance parameters of the SPR biosensor, we calculate, theoretically, the reflectance spectra of the proposed model and analysed it. The investigation of various performance parameters i.e., sensitivity, detection accuracy, and quality factor, of sensor configuration are theoretically done with the optimized thickness of silver (55 nm), silicon nitride (5 nm), molybdenum trioxide (10 nm), and graphene oxide (2.55 nm) respectively. The sensitivity, detection accuracy, and figure of merit for the proposed SPR structure are found at 301 deg./RIU, 4.01, and 133 RIU−1 respectively for the detection of IgG. Furthermore, the present SPR biosensor shows improved sensitivity as compared to the other reported works. The refractive index of the analyte changes from 1.33 to 1.37 due to adsorption of the analyte at the GO surface. The proposed sensor design can detect the small change in the refractive index of the sensing media doped with the analyte. © 2022, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.
Enhanced Visible Light Photocatalytic Performance of CeO2@Acidified g-C3N4 Nanoheterostructures for RhB Degradation
(American Chemical Society, 2025) Ashish Kumar; Vaibhav Arya; Amit Pathak; Suverna Trivedi; Debanjan Guin; Chandra Shekhar Pati Tripathi
Photocatalysis with visible light is emerging as an effective solution for tackling environmental concerns, specifically focusing on the removal of dye pollution from wastewater. In this work, we have developed a scalable and efficient route for the synthesis of a (CeO2@CN) nanocomposite by in situ co-pyrolysis of the cerium adipate complex and melamine, followed by acidification and exfoliation of the nanocomposite (CeO2@A-gCN) for the degradation of rhodamine (RhB) dye in visible light. The synthesized photocatalysts were characterized by sophisticated techniques: X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy, UV-vis diffuse reflectance spectroscopy, zeta potential, Brunauer-Emmett-Teller surface area measurements, and electrochemical impedance spectroscopy. The microstructure analysis confirmed the formation of an effective n-n type heterojunction with intimate close contact. The sample 3%CeO2@A-gCN shows complete degradation compared to pristine CN (63%) and 3%CeO2@CN (70%) with respective rate constant values of 0.011, 0.005, and 0.006 min-1. The enhanced photocatalytic efficiency was due to synergistic interaction between the energy levels of CeO2 and A-gCN, leading to highly improved photogenerated charge carrier separation, enhancement in specific surface area, reduced interfacial charge transfer resistance, and improved charge carrier transport. The charge separation and degradation mechanism was investigated in detail using photoluminescence spectroscopy, quenching and quantification experiments, and transient current response under light irradiation. 3%CeO2@A-gCN demonstrated consistent stability, highlighting its suitability for practical wastewater treatment applications. © 2025 American Chemical Society.