• SAMRITI THAKUR

      Articles written in Bulletin of Materials Science

    • Surface structure, morphology and crystal phase-dependent photoactivity of MnO$_2$ nanocatalysts under sunlight

      SAMRITI THAKUR DEVANSHI TINNA BONAMALI PAL

      More Details Abstract Fulltext PDF

      MnO$_2$ exhibits numerous catalytic applications owing to its wide structural diversity with different chemical and physical properties. Different morphologies of MnO$_2$ nanomaterial have been prepared to investigate oxidation of methylene blue dye and reduction of nitrobenzene under natural sunlight. MnO$_2$ nanostructures displayed versatile photoactivity due to different surface and crystal structural morphologies. The prepared materials were characterized by XRD, SEM, EDS, DRS, DLS and fluorescence spectroscopy. The change in absorption maxima from 441 (sea urchin) to 444 nm (nanospheres) is due to change in shape, size and exposure of surface ligand density. Particle size distribution of ${\alpha}$-MnO$_2$ nanorods, sea urchin is 51 and 90–190 nm, respectively, with body-centred tetragonal crystalline structure. The structure of synthesized polymorphs consists of octahedral (MnO$_6$) with different arrangements of edge and phase sharing. From SEM, variation in shapes from sea urchin to nanorods to nanospheres can be seen. MnO$_2$-sea urchin (98%) and ${\alpha}$-MnO$_2$ nanorods (91%) give better activity in photo-oxidation of dye relative to MnO$_2$ nanospheres. The overall photooxidation reaction follows pseudo first-order kinetics. Nitrobenzene (25 ${\mu}$mol) is selectively reduced to 80% aniline (20.5 ${\mu}$mol) by ${\alpha}$-nanotubes of MnO$_2$ catalyst and 82.2% with MnO$_2$-sea urchin photocatalyst. This paper explored thecorrelations between shape-dependent chemical and structural factors of surface of a catalyst. The excellent performance of hierarchical MnO$_2$ represents a potential heterogeneous catalyst for wastewater treatment.

  • Bulletin of Materials Science | News

    • Dr Shanti Swarup Bhatnagar for Science and Technology

      Posted on October 12, 2020

      Prof. Subi Jacob George — Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bengaluru
      Chemical Sciences 2020

      Prof. Surajit Dhara — School of Physics, University of Hyderabad, Hyderabad
      Physical Sciences 2020

    • Editorial Note on Continuous Article Publication

      Posted on July 25, 2019

      Click here for Editorial Note on CAP Mode

© 2021-2022 Indian Academy of Sciences, Bengaluru.