Faculty Publications
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Item Boosting overall electrochemical water splitting via rare earth doped cupric oxide nanoparticles obtained by co-precipitation technique(Elsevier Ltd, 2022) Rodney, J.D.; Deepapriya, S.; Jerome das, S.J.; Robinson, M.C.; Perumal, S.; Sadhana, S.; Periyasamy, P.; Jung, H.; Justin Raj, C.J.The development of electrocatalyst based on nonprecious metals has been a persistent issue as electrochemical water splitting requires electrocatalyst with advanced activity and stability. Further, the electrocatalyst must require low overpotential above the standard potential (>1.23 V) of water splitting to produce hydrogen. This study presents the facile co-precipitation derived rare earth dysprosium (Dy) doped cupric oxide nanoparticles (Cu1−xDyxO) as a non-noble transition metal oxide nanoparticle. The 3 % Dy doped CuO (3 % Dy/CuO) and 1 % Dy doped CuO (1 % Dy/CuO) electrocatalysts showed excellent Oxygen Evolution Reaction (OER) at 1.55 V vs RHE and Hydrogen Evolution Reaction (HER) at − 0.036 V vs RHE in aqueous 1 M KOH aqueous electrolyte to attain the benchmark current density (10 mA cm−2). The stability of the driven electrocatalyst in a bi-functional electrocatalytic setup was monitored for 24 h and was found to be exhibiting a cell voltage of about 2.1 V at 30 mA cm−2 constant current density. Further, the retention capability of the electrode was observed to be 99 % with a very minimal loss. This study hugely suggests the promising consequence of doping rare earth onto a non-precious metal oxide-based electrocatalyst, making it a highly effective bifunctional material for water splitting. © 2022 Elsevier B.V.Item Structural, dielectric and impedance functionalities of La0.01Cu0.99O nanocrystals(Springer, 2023) Deepapriya, S.; Rodney, J.D.; Udayashankar, N.K.The necessity for materials designed with high and low-K dielectric constant having unique thermal stability has been a prime factor for the continuous development of the microelectronics-based industries. To address this issue, pure and 1% lanthanum (La) substituted copper oxide (CuO) nanoparticles were synthesized through an eco-friendly and time effective co-precipitation route for new unanticipated facts. The thermal effisivity of the material was determined by means of photoacoustic spectroscopy (PAS). The dielectric analysis of the monoclinic structured pure and La doped CuO nanoparticles in the frequency range of 1 Hz–1 MHz for various temperatures was noted, Dielectric constant and loss factor had a declining trend with surge in applied frequency and turned out to be independent of frequency at higher frequencies. The AC conductivity observed has confirmed the semi-conducting nature of the nanoparticle and obeyed Jonscher’s universal law. The temperature-dependant electric relaxation process was revealed using complex impedance spectroscopic studies suggesting non-Debye type behaviour of the material. The electrical activity of the nanoparticles is established for the circuit model devised from the calculated relaxation time constant. The impact of the thermal property and the hopping mechanism in the material with indices of interest is confirmed from the electric modulus. The obtained impedance spectra indicate the effect of lanthanum on the grain boundaries and the higher basicity and electropositive nature of lanthanum on the dielectric relaxation process. © 2023, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.Item Modified matrix of ZnO prismoid structures for improved photocatalytic activity: A theoretical and experimental insight(Elsevier B.V., 2024) Manohar, A.; Kompa, A.; Christopher, B.; Shil, S.; Rao, K.; Udayshankar, N.K.; Mahesha, M.G.; Singh, V.; U, U.Currently, the world needs low-cost and high-performance photocatalysts to degrade the carcinogenic pollutant from water. In the present work, a modified ZnO matrix using Mg as a dopant has been reported with theoretical and experimental results to highlight its structure and functions on photocatalytic activity. A versatile chemical co-precipitation technique was employed to get the Mg-ZnO nanostructures. Structural characterization by high-resolution transmission electron microscopy (HRTEM) and X-ray diffraction (XRD) studies show the formation of hexagonal wurtzite structures with no impurity phases. Optical studies confirm the formation of ZnO with intrinsic defects after modifying the matrix, which agrees with the band structure calculations computed using density functional theory (DFT). Mg-modified ZnO introduced intrinsic defects like vacancies and interstitials that have a great impact on applications like photocatalysis. Based on these supporting results we employed prepared samples for dye degradation, which performed well (80% degradation efficiency) in a short period of UV irradiation. This could be a promising technology for environmental remediation. © 2023 Elsevier B.V.Item Soot Oxidation Kinetics on Nickel Oxide: Effects of Various Synthesis Techniques(Pleiades Publishing, 2024) Patil, S.S.; Prasad Dasari, H.P.; Gouramma, P.; Harshini, H.Abstract: Nickel oxide (NiO) nanoparticles were synthesized using four different methods: microwave co-precipitation (MCP), solution combustion synthesis (SCS), direct nitrate calcination (DNC), and the sol-gel process (SGP), incorporating organic additives such as glucose and fructose. X-ray diffraction and Raman spectroscopy analyses revealed that the NiO nanoparticles formed a face-centered cubic phase characterized by Ni–O bond stretching. The SCS method produced NiO nanoparticles with higher lattice strain, smaller crystallite size, and an increased facet ratio ({110}) compared to the other methods. Transmission electron microscopy indicated that the order of nano-agglomeration size for the NiO nanoparticles was DNC > MCP > SGP > SCS. The NiO nanoparticles synthesized via SCS, SGP and MCP exhibited irregular hexagonal shapes. Among the synthesized nanoparticles, those produced by the SCS method demonstrated the highest catalytic activity (T50 = 478°C), followed by DNC (T50 = 492°C), MCP (T50 = 495°C), and SGP (T50 = 538°C). A kinetic study was conducted to evaluate key parameters, including activation energy, preexponential factor, and reaction model. The experimental curves of soot conversion were compared with theoretical curves derived from the evaluated kinetic parameters. The NiO nanoparticles synthesized via SCS exhibited the highest kinetic activity with the enhanced reaction rate at lower temperatures. © Pleiades Publishing, Ltd. 2024.Item Novel Ag2Cu2O3 nanorods as stable anode material for lithium-ion battery(Elsevier B.V., 2025) Kumar, A.; Sagar G, L.; P, M.; Hegde, A.P.; Nagaraja, H.S.In this research novel Ag2Cu2O3 nanorods was prepared, for lithium-ion battery as anode, using facile co-precipitation method with four different stirring time and correspondingly Ag2Cu2O3 named ACO – 30 M, ACO – 12 H, ACO – 24 H, and ACO – 36 H. Field Emission Scanning Electron Microscopy (FESEM) and High-Resolution Transmission Electron Microscopy (HRTEM) analyze surface and morphology, while X-ray Diffraction (XRD) examines structural properties. Compositional analysis is carried out using X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy. The electrochemical analysis is evaluated by cyclic stability, rate capability, discharge/charge capacity, electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV). The ACO – 24 H nanomaterial demonstrates an initial discharge capacity of 943 mAh g?1 at a current density of 50 mA g?1. Among the four materials tested, ACO – 24 H shows superior cycling performance, with a discharge capacity of 174 mAh g?1 at 200 mA g?1 after 1003 cycles. In comparison, ACO – 30 M, ACO – 12 H, and ACO – 36 H exhibit capacities of 134 mAh g?1, 91 mAh g?1, and 43 mAh g?1, respectively, under the same conditions. This study suggests that ACO – 24 H is a promising anode material for lithium-ion battery applications. © 2025 Elsevier B.V.