Browsing by Author "Uma, P.I."

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Copper doping induced band structure and morphology transformation in CaTiO3 for textile dye photodegradation applications
(Elsevier Ltd, 2024) Shenoy, U.S.; Uma, P.I.; Bhat, D.K.
Semiconductor metal oxides with a wide bandgap like CaTiO3 can be exploited into an efficient visible light photocatalyst via cation doping. The type of dopant and the site of doping is known to greatly influence the photocatalytic activity of a material. Based on the intricacies of the density functional theory electronic structure study, we delve into the optimization of one-pot solvothermal synthesis to obtain Cu doped CaTiO3 nanocuboids. Doping of copper not only resulted in change in the electronic structure of the material but also led to change in the morphology. The uneven nanostep architecture resulted in increase in the surface area of the catalyst, which led to more active sites for the adsorption of the dyes and subsequent degradation. The reduced band gap and decreased recombination of charge carriers made the copper doped calcium titanate an efficient photocatalyst for degradation of both cationic (99.7% degradation of MV dye in 120 minutes) and anionic (99.8% degradation of RB in 45 minutes) dyes. © 2024 Elsevier B.V.
Designing sustainable porous graphene-CaTiO3 nanocomposite for environmental remediation
(Elsevier B.V., 2024) Bhat, D.K.; Bantawal, H.; Uma, P.I.; Kumar, S.P.; Shenoy, U.S.
In the pursuit of sustainable energy and environmental solutions, photocatalysis has emerged as a transformative technology, harnessing the power of light to drive chemical transformations. Among the myriad photocatalytic materials, calcium titanate (CaTiO3) stands out as a promising candidate, holding the potential to revolutionize the landscape of photocatalysis. To further improvise the efficiency of CaTiO3 in this work, porous graphene-CaTiO3 nanocomposite was synthesized by a straightforward solvothermal method and its photocatalytic activity was tested for the degradation of methylene blue dye under visible light. The synthesized sample exhibited 98.1% degradation in 40 min with excellent cyclic stability. Experimental and computational analysis attributed the enhanced performance to the strong chemical interaction of CaTiO3 cuboids with PG sheets via Ti-O-C bond which led to efficient electron hole separation leading to enhanced lifetime of the charge carriers. This along with reduced band gap and increased surface area made the material a potent photocatalyst for the degradation of dyes in short duration. © 2024 The Authors
Doped BaTiO3 cuboctahedral nanoparticles: Role of copper in photocatalytic degradation of dyes
(Elsevier B.V., 2023) Uma, P.I.; Shenoy, U.S.; Bhat, D.K.
The discovery of perovskite oxides as photocatalysts has opened unique possibilities for the degradation of pollutants such as dyes. In this work, we carry out both theoretical and experimental study for the design and preparation of copper doped BaTiO3. To begin with, First principles electronic structure calculations revealed the presence of additional levels at the top of the valence band after doping copper, which considerably decreased the band gap making the oxide visible light active. Later, single pot synthesis of copper doped BaTiO3 led to production of a material which was photocatalytically active in degrading both cationic and anionic dyes. From our work, we found that the photocatalyst 0.5 CuBTO decomposed 98.2% of methylene blue dye in 120 min and 99.4% of rose bengal dye within 45 min. Such high efficiency was attributed to the high surface area, appropriate band gap and low recombination rate of the charge carriers. © 2023
Electronic structure engineering of BaTiO3 cuboctahedrons by doping copper to enhance the photocatalytic activity for environmental remediation
(Elsevier Ltd, 2023) Uma, P.I.; Shenoy, U.S.; Bhat, D.K.
The advent of perovskites as an efficient photocatalyst has paved the way to newer possibilities in the degradation of contaminants such as dyes and toxic heavy metal ions. The alleged poor photocatalyst BaTiO3 was engineered to perform better by decreasing its bandgap to make it visible light active via doping. The high-risk factor in the reduction of the bandgap is the formation of recombination centers for the charge carriers which decreases the efficiency of the photocatalyst. Herein, we studied the electronic structure tuning of BaTiO3 by doping copper and developed a one pot synthesis method to obtain copper doped BaTiO3 that has a high surface area, lower recombination rate, and higher photocatalytic efficiency towards dye degradation and hexavalent chromium ion reduction. The 0.5 CuBT sample had a photocatalytic efficiency of 99.4 % for methyl violet decomposition within 120 min and 99.8 % for hexavalent chromium ion reduction by fructose in 20 min. © 2023 Elsevier B.V.
Exceptional light harvesting in copper doped CaTiO3 nanocuboids with surface nanosteps for the photo remediation of toxic Cr(VI) ions and dyes
(Elsevier B.V., 2024) Bhat, D.K.; Uma, P.I.; Shenoy, U.S.
Addressing the rising concerns of water pollution caused by harmful inorganic and organic contaminants is very crucial and photocatalysts with exceptional light harvesting capability are a promising way to tackle these issues. This study investigates the transformation of CaTiO3 into a visible light-active photocatalyst via copper doping. Copper-doped CaTiO3 nanocuboids were synthesized via a one-step solvothermal approach, resulting in the formation of distinctive nanostep substructures on the surface. Morphological analysis revealed the successful incorporation of copper ions into the perovskite matrix, as evidenced by the transition from smooth to rough, uneven surface features. X-ray diffraction confirmed the incorporation of Cu2+ ions into the Ti4+ site, while visible range absorption indicated a reduction in the bandgap. Furthermore, doping decreased the rate of charge carrier recombination and increased their average lifetime, prolonging the duration of active species. This modification facilitating efficient absorption of visible light and increase in the charge separation, leads to enhanced photocatalytic activity. The doped catalyst exhibited exceptional performance in the remediation of hexavalent chromium ions (98.5 % Cr6+ ions reduction to Cr3+ ions in 20 min), methylene blue (99.4 % degradation within 120 min), and eosin yellow (99.8 % degradation within 80 min) pollutants. This research underscores the potential of doping as a viable strategy for tailoring photocatalytic properties and addressing water pollution challenges. © 2024 Elsevier B.V.