Browsing by Author "A. Ramesh"
Now showing 1 - 4 of 4
- Results Per Page
- Sort Options
PublicationArticle Graphene decorated with Fe nanoclusters for improving the hydrogen sorption kinetics of MgH 2 - Experimental and theoretical evidence(Royal Society of Chemistry, 2016) M. Sterlin Leo Hudson; Keisuke Takahashi; A. Ramesh; Seema Awasthi; Ashish Kumar Ghosh; Ponniah Ravindran; Onkar Nath SrivastavaGraphene decorated with Fe clusters is proposed to be a possible alternative catalyst for the hydrogenation and dehydrogenation reactions of MgH 2 . In particular, graphene decorated with Fe clusters is effective for both hydrogenation and dehydrogenation processes of MgH 2 . The change in enthalpy and entropy values of hydrogen absorption determined for MgH 2 with 5 wt% graphene decorated with Fe clusters is -50.4 ± 2.9 kJ per mole of H 2 and 99.8 ± 5.2 J K -1 per mole of H 2 , respectively. This is significantly lower than those for well-established metal catalysts and nano-interfacial confined MgH 2 . Moreover, the graphene decorated with Fe clusters facilitates the fast rehydrogenation kinetics of MgH 2 , which reabsorbed 90% of the total reabsorption capacity in less than 4 minutes at 300 °C and 20 atm. In addition, TEM analysis reveals that MgH 2 particles are covered by graphene with Fe clusters, resulting in the reduction of grain growth. Density functional theory shows that the defects in graphene act as the active sites for the dehydrogenation of MgH 2 , while the Fe clusters reduce the adsorption of dissociated H atoms, resulting in low-temperature dehydrogenation. Thus, graphene decorated with metal clusters could open up a new way of designing a new type of catalyst which could replace transition metal catalysts. © The Royal Society of Chemistry 2016.PublicationArticle Highly sensitive organic electrochemical transistor for detection of stress-induced cation leakage from plant cells(Elsevier Ltd, 2022) Jeyavelan M; Farheen Khurshid; M. Akhil; R. Rathes Kannan; A. Ramesh; S. Nagarajan; Mario Hofmann; M. Sterlin Leo HudsonStress-induced ionic leakage plays a key role in understanding plant physiology. The ability of the plant cell membrane to withstand environmental stress factors can be gauged through monitoring of cation (especially K+) leakage. In this study, we have developed a PEDOT:PSS polymer-based organic electrochemical transistor (OECT) for detecting the discharged cations from Tephrosia purpurea leaf samples under hyperthermal stress. The test leaf samples were exposed to different heat stress environments and the discharged ions from the stress-treated leaf samples were collected in DI water through incubation. The cation detection was then performed via depletion mode operation of OECTs. Our analysis revealed that the OECTs are highly sensitive toward cation detection under low operating voltage (<1 V). In addition, OECTs are sensitive even at cation concentrations below 5 ppm. The present approach of cation detection through OECT provides a new way of understanding plant physiology. © 2022 The Author(s)PublicationArticle Radially aligned CNTs derived carbon hollow cylinder architecture for efficient energy storage(Elsevier Ltd, 2020) Prashant Tripathi; Ashish Bhatnagar; A. Ramesh; Alok K. Vishwakarma; Sweta Singh; Deepa B. Bailmare; Abhay D. Deshmukh; Bipin Kumar Gupta; O.N. SrivastavaTo explore the practical feasibility of exotic carbon, various types of geometries of CNT configurations have been investigated such as CNT film, vertically aligned nanotubes, 3D pillared graphene-CNT network etc. High-performance and applicability of CNT derived electrodes in electrochemical energy storage depend on the structural design and high aspect ratio geometry. Here, we have strategically designed electrode derived from a special type of 3D geometry known as carbon hollow cylinders (CHCs) made up of CNTs arranged in the radial direction. The exceptional geometry provides a high areal capacity of 513.92 C/cm2 at an applied current density of 16 mA/cm2. Also, high specific energy of 41.13 mWh/cm2 at the specific power of 5694.92 mW/cm2 originated from supercapacitors and battery response of the electrode material was attained, which idealized the fundamental of theory of composite type electrode material. Hence, proposed geometry sets a stepping stone for a paradigm shift in light-weight electrode which is not only binder-free but also designed with a special geometry that provides an exceptional higher areal capacity with stable network. © 2020 Elsevier LtdPublicationArticle Supercapacitor and room temperature H, CO2 and CH4 gas storage characteristics of commercial nanoporous activated carbon(Elsevier Ltd, 2021) A. Ramesh; M. Jeyavelan; J.A. Alex Rajju Balan; O.N. Srivastava; M. Sterlin Leo HudsonThis paper discusses the electrochemical energy storage and room temperature hydrogen, methane and carbon dioxide adsorption/desorption behaviour of commercial nanoporous activated carbon having a specific BET surface area 1007 m2 g−1 and pore volume 0.371 cm3 g−1. The electrochemical energy storage behaviour of activated carbon was determined from its capacitive performance using standard three and two-electrode cells. The specific capacitance (CS) of the sample determined using a three-electrode cell is 138 F g−1 at 0.1 A g−1 with the capacitance loss of 1% after 2000 charge/discharge cycles. Whereas, CS determined using a two-electrode cell is 98.8 F g−1 at 0.2 A g−1 with the capacitance loss of 3% after 5000 charge/discharge cycles. The energy and power densities of two-electrode cell supercapacitor is 19.76 Wh kg−1 and 3.77 kW kg−1, respectively. The sample exhibits gaseous uptake capacities of 0.23 wt% H2, 8.52 wt% CH4 and 37.25 wt% CO2 at ~50 atm/293 K. © 2021 Elsevier Ltd