Faculty Publications

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Author: search.filters.author.Udayashankar, N.K.Subject: search.filters.subject.Degradation

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    Visible-light-driven photocatalytic degradation of organic dyes over cubic-phase and hexagonal-phase CdS: a comparative study
    (Springer, 2023) Mahendra, K.; Anupriya, J.; Gajendra, N.; Madhusudhan, C.K.; Nagaraja, B.S.; Pattar, J.; Udayashankar, N.K.
    Organic effluents—the gift of industrial development is a critical menace to environs as well as raising a question mark toward the sustainability of humans. In such a scenario, achieving consistent sunlight-driven photocatalytic degradation gains widespread attention due to its eco-friendly low-cost approach with high efficiency. Herein, the CdS-cubic nanoparticles have been synthesized using a simple chemical precipitation technique and structural transition to CdS hexagonal is obtained through annealing. Morphology study has validated the reduction in particle size of CdS cubic and corresponding enhancement in the surface are put forth by BET analysis. The better degradation capability of CdS cubic is demonstrated through the visible-light-driven photocatalysis of MB dye with a degradation rate constant of k = 0.02/min. Meanwhile, CdS hexagonal possesses a rate constant k = 0.005/min. The scavenger study reveals the vital role of conduction band electron and superoxide radical in decolorization. Moreover, lesser carrier recombination with more charge transfer is observed from PL and EIS, respectively, emphasizing the CdS-cubic nanoparticle's catalytic activity. © 2023, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.
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    Bi-functional LaMxFe1-xO3 (M = Cu, Co, Ni) for photo-fenton degradation of methylene blue and photoelectrochemical water splitting
    (Elsevier Ltd, 2023) James, A.; Rodney, J.D.; Rao, L.; Badekai Ramachandra, B.R.; Udayashankar, N.K.
    Due to growing concern over environmental remediation and the energy crisis, perovskite nanoparticles have gained wide interest in converting solar energy to sustainable fuel and also in degrading organic effluents. Herein, we report the synthesis and bi-functional activity of one-pot-glycine combustion derived LaMxFe1-xO3 (M = Cu, Co, Ni; x = 0, 0.01) for photo-Fenton degradation of Methylene Blue (MB) and photoelectrochemical water splitting. When used as a photocatalyst, with partial substitution of Cu even at a lower concentration, LaCu0.01Fe0.99O3 has exhibited excellent degradation efficiency of 96.4% in 90 min, which is 2.5 times better than the LaFeO3. On the other hand, Co and Ni modified LaFeO3 photocatalysts have demonstrated prominent activities with degradation efficiency of 93.8% and 74.8% respectively within 180 min of visible light irradiation. The retention and reusability analysis showed that LaCu0.01Fe0.99O3 is stable against photo corrosion and remains unchanged after 5 consecutive cycles of MB dye degradation. In addition, LaCu0.01Fe0.99O3 is complimented as a single catalyst for dual functions such as photocatalysis and electrocatalysis, both of which are assisted by visible light. Under illumination, the overpotential (η) improved from 507.6 mV vs RHE (dark) to 498.1 mV vs RHE (light) for O2 evolution and 220.5 mV vs RHE (dark) to 182.8 mV vs RHE (light) for H2 generation respectively. The light response of the catalyst and improvement in activity is validated by the significant enhancement in current density under exposure at both half cycle of chronoamperometry. © 2023 Hydrogen Energy Publications LLC
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    Mechanistic insights and DFT analysis of bimetal doped styrofoam-like LaFeO3 perovskites with in-built dual redox couples for enhanced Photo-Fenton degradation of Tetracycline
    (Elsevier B.V., 2024) James, A.; Naik, S.; Rodney, J.D.; Joshi, S.; Udayakumar, U.; Kim, B.C.; Udayashankar, N.K.
    The rising number of contaminants released into the environment and the inadequacies of traditional wastewater treatment techniques have led to the demand for enhanced oxidation technologies like photo-Fenton. In this study, bimetal co-doped lanthanum orthoferrite (BixLa1-xCuyFe1-yO3 (x = 0, 0.01, 0.05, 0.1; y = 0, 0.01, 0.05, 0.1, 0.15)) based photo-Fenton catalysts with the in-built redox couples Fe3+/Fe2+, Cu2+/Cu+ and oxygen vacancies have been successfully synthesised via a facile one-pot solution combustion route. Systematic studies show that the Bi0.05La0.95Cu0.1Fe0.9O3 (LFOBC) exhibits an optimal photo-Fenton degradation rate of 0.0497/min for Tetracycline (TC) removal, being ∼ 1.8 and ∼ 6.2 times greater than Bi0.05La0.95FeO3 (LFOB) and pristine LaFeO3 (LFO) respectively. DFT analysis confirmed the better adsorption and dissociation of H2O2 on a bimetal co-doped catalyst and identified the electron density difference in LFOBC, which can induce the H2O2 dissociation. A detailed investigation of various influencing reaction parameters is explored. The degradation pathway for the LFOBC catalyst with the toxicological characteristics of each intermediate is analysed. This study presents the Bi0.05La0.95Cu0.1Fe0.9O3 as a potential photocatalyst for enhanced photo-Fenton degradation with excellent efficiency observed for the degradation of various harmful pollutants for environmental remediation. © 2024 Elsevier B.V.