Browsing by Author "Shaikh Mohammed Zaeem"

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Mesoporous Mn3O4 coated reduced graphene oxide for high-performance supercapacitor applications
(Institute of Physics Publishing, 2019) Biplab Kumar Kuila; Shaikh Mohammed Zaeem; Soumili Daripa; Kanak Kaushik; Saral Kumar Gupta; Santanu Das
We report the facile synthesis of mesoporous Mn3O4 coated reduced graphene oxide (rGO) nanocomposite using a simple low temperature wet chemical process and demonstrated the nanocomposite material as high-performance electrodes for electrochemical supercapacitor. The nanocomposite structure is unique as it consists of an ultra-thin, mesoporous (pore size ∼1.9-2.6 nm) with oriented pore size of Mn3O4 layer deposited on the surface of rGO. The structure and the orientation of nanopores in the Mn3O4 layer were further confirmed using HRTEM, while structural and morphological analysis were carried out using XRD, Raman spectroscopy, SEM, TEM, and SAED. The pore size and the pore distributions were verified using BET surface area technique, which demonstrated the nanocomposite exhibits uniform distribution of pores of dimension ∼1.9-2.6 nm throughout. The electrocatalytic behavior of the nanocomposite was found to be ideal for their use as supercapacitor electrodes as high-performance charge storage devices. Finally, we demonstrate the supercapacitor electrode using Mn3O4-rGO nanocomposite followed by their electrochemical characterizations for electrocatalytic activity for charge storage. The hybrid material shows best capacitance value of 221 F g-1 at current density 0.15 A g-1 with good cycling stability. We believe that our investigations will pave a pathway towards various new applications, including, electrochemical catalysis, sensing, energy harvesting and storage and many more. © 2018 IOP Publishing Ltd.
Mn3O4 nanocluster-graphene hybrid for energy storage and electrochemical sensing application
(Springer, 2020) Soumili Daripa; Shaikh Mohammed Zaeem; Biplab Kumar Kuila; Santanu Das
In this report, uniformly dispersed tri-manganese tetra-oxide (Mn3O4) nanoclusters on reduced graphene oxide (rGO) were synthesized and used as an electrode material for high-performance supercapacitor application. HRTEM images associated with SAED and EDS confirm the formation of Mn3O4 nanoclusters on rGO while FTIR shows clear evidence of Mn3O4 nanocluster deposition on rGO. The nanohybrid structure is unique showing uniformly distributed Mn3O4 nanoclusters of size from 2 to 20 nm with the majorities of the cluster sizes are in the range of ~ 5–11 nm. The nanoclusters exhibit trapped mesopores of size ~ 2 nm inside of the clusters surrounded with tiny Mn3O4 nanoparticles, which not only improves the surface properties but also enhances the electrochemical activities of rGO. We believe that the low-temperature, hydrothermal processing of KMnO4 solution leads to the development of such nanoclusters formed by limited growth of ultra-nanosized nucleates deposited on rGO surface under optimized time condition. The nanohybrid shows the highest capacitance value of 181 F/g at a current density of 0.3 A/g along with superior cyclic stability (with ~ 95% capacitance retention upon continuous 2000 cycle). The nanohybrid material was further utilized for electrochemical sensing of H2O2 where anodic current proportionally increases as a function of H2O2 concentrations. We believe that the nanohybrid material described here will have potential applications in the area of high-performance supercapacitor, catalysis, batteries, and non-enzymatic sensors. © 2019, Springer-Verlag GmbH Germany, part of Springer Nature.