Browsing by Author "Manjunath, Vishesh"

Now showing 1 - 2 of 2
  • No Thumbnail Available
    Item
    Experimental investigations on morphology controlled bifunctional NiO nano-electrocatalysts for oxygen and hydrogen evolution
    (Elsevier Ltd, 2022-09-27T00:00:00) Manjunath, Vishesh; Bimli, Santosh; Biswas, Rathindranath; Didwal, Pravin N.; Haldar, Krishna K.; Mahajan, Mangesh; Deshpande, Nishad G.; Bhobe, Preeti A.; Devan, Rupesh S.
    Developing a single electrocatalyst effective for both oxygen and hydrogen evolution remains challenging. Although an attempt to utilize a single electrocatalyst for overall water splitting is made, there still exist several issues of efficiency and stability of the electrocatalyst. Hence, the present study reports on morphology-controlled NiO electrocatalyst, a single electrocatalyst for oxygen and hydrogen evolution. The cubic phase NiO nanoparticles and nanoplates of diameter and thickness <10 nm delivered surface-to-volume ratios of 0.078 and 0.083, respectively. XRD and TEM confirm the formation of NiO nanostructures, where morphology transformed independently of the chemical composition. XPS and EXAFS confirm the 2+ oxidation state of Ni ions and its octahedral coordination with oxygen. The 0D nanoparticles providing a larger surface area and active sites offered the overpotentials of 373 and 268 mV for OER and HER activity, respectively, and performed well than the 2D porous NiO nanoplates. The chronoamperometry and repetitive LSV cyclic studies confirmed the excellent long-term stability of 0D NiO nanoparticles in basic and acidic mediums during electrocatalytic water splitting reactions, owing to its increased electrochemically exposed active sites. � 2022 Hydrogen Energy Publications LLC
  • No Thumbnail Available
    Item
    Porous nanorods by stacked NiO nanoparticulate exhibiting corn-like structure for sustainable environmental and energy applications
    (Royal Society of Chemistry, 2023-07-20T00:00:00) Manjunath, Vishesh; Bimli, Santosh; Singh, Diwakar; Biswas, Rathindranath; Didwal, Pravin N.; Haldar, Krishna Kanta; Deshpande, Nishad G.; Bhobe, Preeti A.; Devan, Rupesh S.
    A porous 1D nanostructure provides much shorter electron transport pathways, thereby helping to improve the life cycle of the device and overcome poor ionic and electronic conductivity, interfacial impedance between electrode-electrolyte interface, and low volumetric energy density. In view of this, we report on the feasibility of 1D porous NiO nanorods comprising interlocked NiO nanoparticles as an active electrode for capturing greenhouse CO2, effective supercapacitors, and efficient electrocatalytic water-splitting applications. The nanorods with a size less than 100 nm were formed by stacking cubic crystalline NiO nanoparticles with dimensions less than 10 nm, providing the necessary porosity. The existence of Ni2+ and its octahedral coordination with O2? is corroborated by XPS and EXAFS. The SAXS profile and BET analysis showed 84.731 m2 g?1 surface area for the porous NiO nanorods. The NiO nanorods provided significant surface-area and the active-surface-sites thus yielded a CO2 uptake of 63 mmol g?1 at 273 K via physisorption, a specific-capacitance (CS) of 368 F g?1, along with a retention of 76.84% after 2500 cycles, and worthy electrocatalytic water splitting with an overpotential of 345 and 441 mV for HER and OER activities, respectively. Therefore, the porous 1D NiO as an active electrode shows multifunctionality toward sustainable environmental and energy applications. � 2023 The Royal Society of Chemistry.