Publications by authors named "Bharath Velaga"

2 Publications

  • Page 1 of 1

Hybridization of Pd Nanoparticles with UiO-66(Hf) Metal-Organic Framework and the Effect of Nanostructure on the Catalytic Properties.

Chemistry 2018 Oct 5;24(60):15978-15982. Epub 2018 Oct 5.

Materials Science Division, Poornaprajna Institute of Scientific Research, Devanahalli, Bangalore Rural-, 562164, India.

Metal-organic frameworks (MOFs) have emerged as a new class of supports for metal nanoparticles(NPs) in heterogeneous catalysis because of possible synergetic effects between the two components. In addition, MOFs also can be coated over metal NPs to influence the entire nanoparticle's surface. Herein, NPs were hybridized with UiO-66(Hf) MOF possessing Brønsted acidic sites (on secondary building units) and fabricated [email protected] (Hf) core-shell and Pd/UiO-66(Hf) supported catalysts. These hybrid materials exhibited enhanced catalytic properties (TOF increased up to 2.5 times) compared to individual counterparts or their physical mixture for dehydrogenation of ammonia borane(AB) in non-aqueous medium(1,4-dioxane). Further, nanostructure of the hybrid material had pronounced influence on the catalytic properties. The core-shell catalyst exhibited highest activity towards H generation from AB owing to greater contact interface between Pd and MOF. Further, phenylacetylene semi-hydrogenation with AB over [email protected] (Hf) furnished styrene selectivity as high as 93.2 % at ∼100 % conversion mostly due to the regulated phenylacetylene diffusion through UiO-66(Hf) shell.
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October 2018

High Surface Area SnO -Ta O Composite for Visible Light-driven Photocatalytic Degradation of an Organic Dye.

Photochem Photobiol 2018 07 26;94(4):633-640. Epub 2018 Apr 26.

Functional Nanomaterials Group, Materials Science Division, Poornaprajna Institute of Scientific Research, Devanahalli, Bengaluru, Karnataka, India.

SnO -Ta O nanocomposite was synthesized by a facile coprecipitation method and further calcined to obtain crystalline powder. Phase formation, morphology, bandgap and photocatalytic properties were analyzed using powder X-ray diffraction, scanning electron microscopy, UV-Vis diffused reflectance spectroscopy, BET surface area and Raman spectroscopy, respectively. Effect of calcination temperature on the crystallinity of the composite was studied. The as-prepared samples of SnO , Ta O and SnO -10wt%Ta O composite as well as the calcined composite sample were tested for photocatalytic activity for methylene blue dye degradation under visible light. Photocatalytic studies reveal that the as-prepared SnO -10wt%Ta O composite showed the best photocatalytic activity for the degradation of methylene blue (MB) by harvesting visible-light radiation efficiently. Further mineralization of methylene blue, estimated by COD analysis, is found to have degraded with an efficiency of 91.6%. The study demonstrates that heterostructure of SnO -Ta O nanocomposite could be applied in photocatalytic purification of organic pollutants.
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July 2018