Browsing by Author "Sridharan K."

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    Advanced two-dimensional heterojunction photocatalysts of stoichiometric and non-stoichiometric bismuth oxyhalides with graphitic carbon nitride for sustainable energy and environmental applications
    (2021) Sridharan K.; Shenoy S.; Kumar S.G.; Terashima C.; Fujishima A.; Pitchaimuthu S.
    Semiconductor-based photocatalysis has been identified as an encouraging approach for solving the two main challenging problems, viz., remedying our polluted environment and the generation of sustainable chemical energy. Stoichiometric and non-stoichiometric bismuth oxyhalides (BiOX and BixOyXz where X = Cl, Br, and I) are a relatively new class of semiconductors that have attracted considerable interest for photocatalysis applications due to attributes, viz., high stability, suitable band structure, modifiable energy bandgap and two-dimensional layered structure capable of generating an internal electric field. Recently, the construction of heterojunction photocatalysts, especially 2D/2D systems, has convincingly drawn momentous attention practicably owing to the productive influence of having two dissimilar layered semiconductors in face-to-face contact with each other. This review has systematically summarized the recent progress on the 2D/2D heterojunction constructed between BiOX/BixOyXz with graphitic carbon nitride (g-C3N4). The band structure of individual components, various fabrication methods, different strategies developed for improving the photocatalytic performance and their applications in the degradation of various organic contaminants, hydrogen (H2) evolution, carbon dioxide (CO2) reduction, nitrogen (N2) fixation and the organic synthesis of clean chemicals are summarized. The perspectives and plausible opportunities for developing high performance BiOX/BixOyXz-g-C3N4 heterojunction photocatalysts are also discussed. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.
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    Bimetallic nanoparticles grafted ZnO hierarchical structures as efficient visible light driven photocatalyst: An experimental and theoretical study
    (2021) Shenoy S.; Tarafder K.; Sridharan K.
    Bimetallic nanoparticles (NPs) exhibiting novel properties due to synergy between the individual elements have sparkled significant interest as a co-catalyst in enhancing the photocatalytic efficiency of semiconductor materials. Here, we report the photocatalytic activity of NiAg NPs embedded on hierarchical ZnO structures (NiAg-ZnO). Structural and morphological investigations through X-ray diffraction and scanning electron microscopy confirmed the formation of NiAg-ZnO. UV-Vis diffuse reflectance spectroscopy revealed the decrease in the bandgap energy of NiAg-ZnO (2.65 eV) in comparison to pristine ZnO (3.1 eV). Interestingly, the rate of photodegradation of methylene blue and rhodamine B dye molecules under visible light irradiation are two to three times enhanced with NiAg-ZnO in comparison to Ag-ZnO. Enhanced visible light absorption and effective charge separation due to the synergistic metal-semiconductor interface formed by the embedment of NiAg bimetallic NPs on ZnO led to the improved photocatalytic activity. Experimental results are further confirmed through the first principle electronic band structure calculations. © 2021
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    Bismuth oxybromide nanoplates embedded on activated charcoal as effective visible light driven photocatalyst
    (2020) Shenoy S.; Sridharan K.
    Nanostructured bismuth oxybromide (BiOBr) are one among the most significantly researched visible light driven photocatalyst, but their low specific surface area hinders higher rate of photodegradation. Herein, a single-step solution based synthesis technique is adopted to embed BiOBr on very little quantities of activated charcoal (AC), thereby improving its specific surface area and visible light absorption range. Nanoplate morphology of BiOBr and their embedment on AC are confirmed from electron microscopy. Interestingly, the embedment of BiOBr on just 0.5 wt% of AC (BiOBr-AC0.5) significantly enhanced the rate of salicylic acid photodegradation, which was six-fold higher than that of pristine BiOBr. © 2020 Elsevier B.V.
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    Corrigendum to Novel N-substituted-5-phenyl-1H-pyrazole-4-ethyl carboxylates as potential NLO materials [Arab. J. Chem. (6) (2013) 97-102]
    (2013) Chandrakantha B.; Isloor, A.M.; Sridharan K.; Philip R.; Shetty P.; Padaki M.; Fun H.-K.
    [No abstract available]
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    Graphitic C3N4/CdS composite photocatalyst: Synthesis, characterization and photodegradation of methylene blue under visible light
    (2020) Shenoy S.; Tarafder K.; Sridharan K.
    Design and development of heterojunction photocatalysts is one among the main strategies for improving the photocatalytic activity of semiconductor materials. Here, we report the synthesis of a heterojunction photocatalyst by the embedment of cadmium sulphide (CdS) nanoparticles on the surface of graphitic carbon nitride (g-C3N4) layers through hydrothermal approach. The g-C3N4/CdS heterojunction photocatalyst exhibited two-fold and three-fold enhancement in the photodegradation efficiency in comparison to pristine CdS and g-C3N4, respectively in the removal of 20 ppm methylene blue dye molecules under visible light irradiation. The enhanced photocatalytic activity can be attributed to the formation of heterojunction and the synergistic effect of g-C3N4 and CdS in the promotion of charge separation and charge mobility that was tracked through photoluminescence spectroscopy. © 2020 Elsevier B.V.
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    Rapid sonochemical synthesis of copper doped ZnO grafted on graphene as a multi-component hierarchically structured visible-light-driven photocatalyst
    (2021) Shenoy S.; Ahmed S.; Lo I.M.C.; Singh S.; Sridharan K.
    Three-dimensional (3D) hierarchical structures (HSs) have demonstrated excellent properties for various applications that are attributable to their distinctive micro-sized architecture with nanoscale substructures. Recently, the ultrarapid sonochemical approach was found to be an effective strategy for synthesizing single component HSs with uniform morphologies in comparison to the direct precipitation technique. We here report the fabrication of copper doped zinc oxide grafted on graphene layers (ZnO-Cux-GOy) for exploring the capability of this ultrarapid approach for synthesizing multi-component HSs. Interestingly, the morphology of ZnO-Cux-GOy HSs studied through electron microscopy revealed the growth of ZnO HSs decorated with Cu nanoparticles and interconnected by graphene layers. ZnO-Cux-GOy HSs demonstrated three-fold higher efficiency in the photodegradation of ibuprofen (IBU) under visible light irradiation in comparison to pristine ZnO HSs, which is attributable to the combined influence of the doped Cu2+ ions and graphene, enabling improved visible light absorption and inhibiting the recombination of photogenerated charges. Thus, the novel ultrarapid sonochemical synthesis strategy demonstrated here is anticipated to open up a new horizon for the time-saving and scalable design of multi-component HSs of various materials for a myriad of applications. © 2021 Elsevier Ltd