Faculty Publications

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Author: search.filters.author.Bantawal, H.Subject: search.filters.subject.Photocatalysis

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    Hierarchical porous Batio3 nano-hexagons as a visible light photocatalyst
    (Science Publishing Corporation Inc ijet@sciencepubco.com, 2018) Bantawal, H.; Bhat, D.K.
    Hierarchical porous BaTiO3 nano-hexagons was synthesized via a simple hydrothermal route by using TiO2 and Ba(OH)2.8H2O as starting materials under alkaline environment and its photocatalytic activity was evaluated under visible light by taking methylene blue (MB) as a model pollutant. The prepared BaTiO3 was characterized by powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM), energy dispersive X-rays analysis (EDX), high resolution transmission electron microscopy (HRTEM), Brunauer-Emmett-Teller (BET) analysis and diffused reflectance spectroscopy (DRS) techniques. It is noteworthy that the BaTiO3 nanohexagons exhibited significant photocatalytic activity towards the degradation of MB under visible light irradiation. This significant photocatalytic activity of BaTiO3 under visible light is mainly attributed to the special morphology and formation of Ti3+ defects. © 2018 Authors.
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    Tuning the Photocatalytic Activity of SrTiO3 by Varying the Sr/Ti Ratio: Unusual Effect of Viscosity of the Synthesis Medium
    (American Chemical Society service@acs.org, 2018) Bantawal, H.; Shenoy, U.S.; Bhat, D.K.
    SrTiO3 nanostructures were successfully synthesized in various alcohols as cosolvent as well as surfactant by a facile solvothermal method. The as-synthesized catalysts were characterized by X-ray diffraction technique, scanning electron microscopy, energy-dispersive X-ray analysis, Brunauer-Emmett-Teller analysis, diffuse reflectance spectroscopy, and photoluminescence spectroscopy. The possible formation mechanism of SrTiO3 in the presence of these alcohols is discussed, and the effect of these alcohols on the structure, Sr/Ti atomic ratio, and optical properties is related to the photocatalytic activity. First principles calculations were made use of to determine the effect of defects on the electronic structure and the band gap. The photocatalytic activity of these catalysts was evaluated by taking methylene blue as a model pollutant under visible light irradiation. It was found that the photocatalytic activity of ethanol-mediated SrTiO3 was found to be higher than the other samples because of the synergistic effect of high surface area and lesser defects. © 2018 American Chemical Society.
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    Band Engineering of SrTiO3: Effect of Synthetic Technique and Site Occupancy of Doped Rhodium
    (American Chemical Society service@acs.org, 2018) Shenoy, U.S.; Bantawal, H.; Bhat, D.K.
    It is well known that doping of Rh into the SrTiO3 lattice introduces 4d donor levels within the band gap, which causes reduction in the gap and extends the photocatalytic activity to the visible region of the solar spectrum. The mid-gap states formed also act as recombination centers and diminish the efficiency of the material. Herein, we present a combined theoretical and experimental approach to avoid the formation of the so-called acceptor mid-gap states. For the first time, we study the effect of occupancy of Rh in the Sr site. First-principles calculations reveal that mixed occupancies of Rh into Sr and Ti sites lead to the introduction of acceptor levels within the band gap, leading to decrease in photocatalytic efficiency. A facile one-pot solvothermal approach by avoiding high-temperature calcinations is reported to obtain Rh-doped SrTiO3 nanoparticles in Rh3+ states, suppressing the formation of Rh4+ states by directing Rh toward Sr sites. The photocatalytic activity of Rh-doped SrTiO3 nanoparticles is studied in the case of degradation of methylene blue, wherein the 1.0 Rh sample was found to be highly efficient. © 2018 American Chemical Society.
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    Porous Graphene Wrapped SrTiO3 Nanocomposite: Sr-C Bond as an Effective Coadjutant for High Performance Photocatalytic Degradation of Methylene Blue
    (American Chemical Society service@acs.org, 2019) Bantawal, H.; Sethi, M.; Shenoy, U.S.; Bhat, D.K.
    Porous graphene-SrTiO3 (PGST) composite prepared by a facile solvothermal method was tested for its photocatalytic activity in degradation of methylene blue (MB) dye. First-principles density functional theory calculations were also carried out to study the effect of nanocomposite formation on the electronic structure and density of states. The combined experimental and theoretical study gave insights regarding the formation of the Sr-C bond which enhanced the charge transport, effectively separating the charge carriers and reduced their recombination rate. The formation of PGST nanocomposite favorably tuned the electronic structure with decreased band gap due to introduction of the hybridized states extending the absorption to the visible region of electromagnetic spectrum. The microscopy studies revealed loofah like PG wrapped SrTiO3 nano structures with contusions providing high surface area facilitating adsorption of MB dye. Degradation of ?92% was obtained by 7.5 PGST in 120 min with high cyclic stability indicating its suitability as an efficient photocatalyst for the treatment of pollutants. © 2019 American Chemical Society.
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    Vanadium-Doped SrTiO3 Nanocubes: Insight into role of vanadium in improving the photocatalytic activity
    (Elsevier B.V., 2020) Bantawal, H.; Shenoy, U.S.; Bhat, D.K.
    SrTiO3 based materials have been gaining attention recently in the field of photocatalysis due to their tunable electronic structure. Herein, we employ a facile one pot solvothermal approach for the synthesis of V doped SrTiO3 nanocubes. First principles theoretical calculations reveal that the 3 'd' dopant level introduced by V reduces the band gap and extends the absorption to the visible region of spectrum. The occupancy of Ti site by V introduces dopant states overlapping with the conduction band, eliminating the formation of mid gap recombination centres. Photocatalytic experimental studies on degradation of methylene blue dye reveals the material to be an excellent photocatalyst with high photocorrosion resistance and cyclic stability. In addition, the material is also predicted to be a potential thermoelectric material. © 2020 Elsevier B.V.
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    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