Browsing by Author "Kumar, Harish"

Now showing 1 - 15 of 15
  • No Thumbnail Available
    Item
    CuO/NiO-doped ordered mesoporous carbon for high-performance photocatalytic degradation of dye and energy storage application
    (2026) Kumar, Harish
    Advanced nanomaterials with optimized structures, surfaces, porous characteristics, optimum band gaps, and compositions are crucial for wastewater treatment and energy storage applications. Here, we report the soft- template synthesis of CuO/NiO-doped ordered mesoporous carbon (OMC/CuO/NiO), which exhibits a syner gistic enhancement in photocatalytic and electrochemical performance. The structure testing verified the crea tion of regular mesoporous and effective doping of CuO and NiO into the Carbon framework. The photocatalytic activity of the nanocomposite studied was determined by means of the degradation of methylene blue (MB) dye in the presence of UV–visible light. Light absorption and enhanced charge separation increased the degradation efficiency of the OMC/CuO/NiO nanocomposite to 96 % (improved compared to pure OMC of 55.07 %) and facilitated light absorption and charge separation, respectively. In addition to photocatalysis, OMC/CuO/NiO nanocomposite electrode shows excellent performance as a Supercapacitor with a specific capacitance of 564.2 F g-1 (at 5 mVs-1) and 559.1 F g-1 (at 0.9 Ag-1), which is 3.1-fold higher than undoped OMC (179.7 F g-1). Be sides, GCD profiles reveal the energy density of 49.6 Wh kg-1 and power density of 359.9 W kg-1, which confirms the potential of the material in the fast-charge-discharge processes. Mechanistic studies validate the fact that synergistic redox interactions between Cu and Ni species facilitate the separation of electrons and holes, the production of reactive oxygen species (ROS), and the enhanced photocatalytic activity. These findings make OMC/CuO/NiO a second-generation dual functional material in the form of sustainable wastewater treatment and superior energy storage technologies.
  • Thumbnail Image
    Item
  • Thumbnail Image
    Item
  • Thumbnail Image
    Item
  • Thumbnail Image
    Item
  • No Thumbnail Available
    Item
    Non- template Tailored Macrocyclic Complexes: Synthesis, Characterization, Biological and Computational Studies
    (2025) Kumar, Harish
    Some novel biologically active tetraaza- macrocyclic complexes of Fe (III) and Cr (III) were synthesized by non- template method. In this methodology, first macrocyclic ligand was synthesized by condensation reaction between triethylenetetramine and dime done which was further reacted with trivalent Fe and Cr ions to synthesize the macrocyclic complexes having general formula [M(C14H26N4)(X)](X)2 where X represents Cl−, NO3 −, CH3COO−. Various physiochemical studies suggested the square pyramidal geometry around the metal ion of all complexes. With the aid of PXRD technique, it was found that some of the complexes pos sessed monoclinic crystal system while other complexes showed to have orthorhombic crystal system. The DFT study was also carried out to examine the various quantum descriptors of ligand and its complexes. Moreover, newly synthesized macrocyclic ligand and its complexes with Fe and Cr ions were tested against fungal strain as well various bacterial strains. The results of antibacterial study showed that all complexes exhibited remarkable ability to inhibit the growth of microbes as compared to ligand. All complexes were found to have drug- likeness behavior as indicated by in- silico studies. Furthermore, these complexes were also tested for their antioxidant activity and it was observed that complexes showed better antioxidant activity as compared to ligand and standard solution of ascorbic acid.
  • Thumbnail Image
    Item
  • Thumbnail Image
    Item
  • Thumbnail Image
    Item
    Proficient exclusion of pesticide using humic acid-modified magnetite nanoparticles from aqueous solution
    (Water Science and Technology, 2022) Jangra, Arti; Kumar, Jai; Singh, Devender; Kumar, Harish; Kumar, Parvin; Kumar, Suresh; Kumar, Ramesh
    Extensive dispersal of the pesticides to shield the different types of vegetation from pests has increased the production but at the same it has resulted into increase in environmental pollution. Consequently, it is necessary to eliminate these undesired pollutants from the environment. The current investigation offers the synthesis of humic acid-coated magnetite nanoparticles towards effective removal of the most common insecticide, imidacloprid from the aqueous solution using batch adsorption method. These synthesized nanoparticles were characterized with the help of several analytical and spectroscopic techniques. To acquire the maximum conceivable adsorption, effects of different influencing parameters like pH of the solution, time of contact, concentration of pesticide solution, amount of adsorbent and temperature were also examined. Moreover, the kinetic studies were found to be in good agreement with pseudo-second-order kinetic model supporting the occurrence of chemisorption phenomenon. Additionally, isotherm modeling proved that the adsorption process was in accordance with Langmuir model of isotherm. Thermodynamic parameters depicted the endothermic and spontaneous behavior of the adsorption process. Desorption studies were also carried out to examine the reusability of these nano-adsorbent. These verdicts confirmed that the surface modified magnetite nanoparticles may be treated as proficient material for exclusion of imidacloprid from the aqueous solution.
  • Thumbnail Image
    Item
  • Thumbnail Image
    Item
  • Thumbnail Image
    Item
    Quantum dot decorated polyaniline plastic as a multifunctional nanocomposite: experimental and theoretical approach
    (RSC Advances, 2022) Yadav, Ankita; Kumar, Harish; Sharma, Rahul; Kumari, Rajni; Thakur, Mony
  • No Thumbnail Available
    Item
    Revolutionizing material science: Enhanced functionalities through reduced graphene oxide/Al 2 O 3 /CuO/TiO 2 nanocomposites
    (2025) Kumar, Harish
    Reduced graphene oxide@Al 2 O 3-CuO-TiO 2 (ACT) based nanocomposites (NCs) were combined by regulated hydrothermal technique to create novel rGO@metal oxides-based NCs. The resultant NCs showed excellent photocatalytic, antibacterial, anticorrosive, and magnetic characteristics. The use of FTIR, TEM, UV-visible, X ray diffraction, and SEM aids the structural examination of NCs. The synergistic pairing of ACT NPs with rGO exhibits enhanced photocatalytic, magnetic, anticorrosive, and antibacterial characteristics. The NCs exhibited paramagnetic character ( χ = 0.140) and increased induced current with applied magnetic field. The photo catalytic properties of NCs were examined for decomposing methylene blue dye in UV and Sunlight. 94.7 % and 70.5 % dye degradation was observed under UV and Sunlight after 335 and 110 min. of exposure, respectively. The Zone of Inhibition was examined against S. aureus (Gram-positive) and E. coli (Gram-negative) bacteria and was found comparable with standard antibiotics (Ampicillin) against S. aureus bacterial strain. The NCs show 99 %corrosion inhibition efficiency at a low concentration (10 ppm). The potential applications of ACT@rGO NCs in environmental rehabilitation, the medical field, anticorrosive coatings, and impure water purification, contribute toward the development of advanced nanomaterials-based devices.
  • No Thumbnail Available
    Item
    Structural and photophysical investigation of gadolinium based Eu3 + doped Gd3GaO6 phosphor: A red emitter with high color purity for WLEDs application
    (2026) Kumar, Harish
    To understand different properties of Eu3+ions in inorganic phosphors, a series of red emitting Gd3GaO6:Eu3+ was synthesized via solution combustion method. XRD patterns supported by Rietveld refinement revealed successful formation of crystalline sample with orthorhombic structure and Cmc21 space group. Microstructural features and elemental mapping of samples were examined by means of FE-SEM and EDX techniques. Photo luminescence spectra of Eu3+-activated Gd3GaO6 revealed red emission at 612 nm due to the 5D0→7F2 transition under excitation at 261 nm. A decrease in emission intensity was observed after doping levels exceed 4 mol% indicating energy transfer between activator ions results in concentrating quenching governed via dipole-dipole interactions. The intensity parameters Ω2 and Ω4 defined by Judd Ofelt theory were calculated utilizing emission spectra to investigate coordination symmetry around Eu3+ions. The photoluminescence decay profile was well described by bi-exponential decay function. The activation energy 0.19873 eV suggests good thermal stability of GGO:4 mol% Eu3+phosphor. The high color purity (98.15 %) inferred from CIE coordinates revealed their applicability in white light emitting diodes.
  • No Thumbnail Available
    Item
    Synthesis, C-N/N-N bond conformational analysis and evaluation of naphtho[2,3-d][1,2,3]triazole-4,9-dione tethered N-acyl hydrazones as α-amylase inhibitors: Insights from molecular modeling and ADMET analysis
    (2025) Kumar, Harish
    In an effort to expand the repertoire of potent α-amylase inhibitors, we sought to develop novel inhibitors by combining 1,4-naphthoquinone, 1,2,3-triazole, and N-acyl hydrazone scaffolds in a single matrix. To achieve this, twelve novel naphtho[2,3-d][1,2,3]triazole-4,9‑dione tethered N-acyl hydrazones were synthesized through condensation reaction of 2-(4,9-dioxo-4,9-dihydro-1H-naphtho[2,3-d][1,2,3]triazol-1-yl)acetohydrazide with various substituted aryl aldehydes. Structural elucidation for all the compounds was performed using 1D, 2D- NMR, FTIR, and mass spectral analyses. The synthesized molecules were evaluated for their ability to inhibit α-amylase activity using acarbose as the standard drug. All the derivatives exhibited potent inhibition of α-amylase, with IC50 values ranging between 17.26 ±0.07 to 25.62 ±0.03 μg/mL. Notably, compound 9c possessing –meta substituted –NO2 group displayed the highest activity (IC50 =17.26 ±0.07 μg/mL) among the series. Structure-activity relationship (SAR) revealed the pivotal role of aryl ring substitutions in determining inhibitory efficacy. To validate these findings and to assess the binding stability of 9c within the catalytic site α-amylase dervied for A. oryzae (PDB ID: 7TAA), in silico studies were performed. The compound 9c effectively occupies the enzyme’s active pocket, with minimal RMSD fluctuations observed over 100 ns simulation, indi cating stable protein-ligand complex. ADMET predictions suggested favorable drug-like properties, underscoring the potential of these compounds as novel α-amylase inhibitors for managing type 2 diabetes mellitus