School Of Basic And Applied Sciences

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    One-step hydrothermal synthesis of MoS2 nano-flowers CoS2 square composites electrode materials for supercapacitor application
    (Elsevier Ltd, 2022-07-27T00:00:00) Iqbal, Muzahir; Saykar, Nilesh G.; Kumar Mahanta, Alok; Mahapatra, S.K.
    Developing efficient materials for generating and storing renewable energy is now a pressing test for future energy demand. The advent of (2D) two-dimensional materials has attracted much research interest as electrode materials for supercapacitors due to their intriguing mechanical and electrochemical properties. This report used a facile one-step hydrothermal process to synthesize MoS2@CoS2 Composite as electrode materials for supercapacitors with good energy storage performance and explore energy generation and storage applications. The structure and morphology were investigated by X-ray diffraction pattern, field emission scanning electron microscope consisting of square-shaped CoS2 and flower-like MoS2, and characterization; meanwhile, their electrochemical properties were evaluated by CV, GCD, and EIS measurements. The electrochemical performance of symmetric MoS2@CoS2 binary Composite was examined in 1 M H2SO4 in a two-electrode assembly. The as-prepared MoS2@CoS2 electrode exhibited a specific capacitance of 199F/g at a current density of 2A/g, while its counterpart MoS2 electrode exhibited only 127F/g at 2 A/g current density. The MoS2@CoS2 composite attains specific energy and power densities of 27.74 WhKg?1 and 494.46 Wkg?1, respectively, due to the unique morphology of the MoS2-flowery shape and CoS2 square. CoS2 squares effectively prevent the agglomeration and restacking of MoS2 sheets, facilitating smother ion dynamics. Technological demonstration of MoS2@CoS2 cell is presented by illuminating commercially available light-emitting diode for more than 3 min. � 2022
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    Structural and electrochemical performance of carbon coated molybdenum selenide nanocomposite for supercapacitor applications
    (Elsevier Ltd, 2021-12-14T00:00:00) Tanwar, Shweta; Singh, Nirbhay; Sharma, A.L.
    Among the recent trends of supercapacitor electrode materials, transition metal dichalcogenides based composite materials have become popular due to their ability to have high electronic conductivity, variable oxidation states, large surface area, a porous structure. Herein we report, a composite material based on MoSe2 as electrode prepared using a standard single-step hydrothermal strategy. The structural and morphological study of the prepared material confirms the formation of the composite. The specific surface area has been estimated using BET technique and found to 522 m2 g ? 1 with average pore diameter as 4.6 nm. In all prepared composite electrodes, M@AC 1:5 electrode exhibits the highest specific capacity of 514 F g ? 1 at a scan rate of 10 mV s ? 1 for potential window 1 V in KOH electrolyte solution. The electrochemical impedance spectroscopy (EIS) study of the M@AC 1:5 electrode shows good agreement with cyclic voltammetry and galvanostatic charge-discharge storage mechanism. The aqueous symmetric cell fabricated of M@AC 1:5 with 6 M KOH electrolyte exhibits energy and power density 39.4 Wh kg?1 and 704.5 W kg?1 respectively. It shows long cycle stability with 90% capacitance retention and 100% coulombic efficiency even after 10,000 cycles. Further, the symmetric cell of M@AC 1:5 material was applied for lighting red LED, which illuminated for 22 min. The charging /discharging mechanism has been proposed based on finding of results through different characterizations. The asymmetric supercapacitor has also been designed using two different electrodes (first M@AC 1:5 and second synthetic MWCNT) and shows energy density of 14.9 Wh kg?1 and power density of 496 W kg?1 respectively. The capacitance retention is maintained up to 86.6% while coulombic efficiency recorded 100% for 10,000 cycles. Thus, obtained results highly encouraging and appropriate for the commercial applications. � 2021 Elsevier Ltd
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    High-performance supercapacitor based on MoS2@TiO2 composite for wide range temperature application
    (Elsevier Ltd, 2021-06-07T00:00:00) Iqbal, Muzahir; Saykar, Nilesh G.; Arya, Anil; Banerjee, Indrani; Alegaonkar, Prashant S.; Mahapatra, S.K.
    Transition metal sulphide and their composites gain attention as electrode material in energy storage devices due to their superior properties like excellent conductivity, high surface area, and porosity. We report an evaluation of the electrochemical performance of MoS2@TiO2 binary composite in symmetric supercapacitor assembly at different temperatures. A facile hydrothermal technique is used to prepare MoS2@TiO2 binary composite. Structural and morphological analysis reveals that highly crystalline composite comprising MoS2 assembled in flower-like flake configuration, whereas, TiO2 in nanorods form are prepared. Among all three electrodes, MoS2@15%TiO2 demonstrates maximum specific capacitance 210 F/g at 10 mV/s with excellent cycling stability (98%, 2000 cycles) at ambient temperature. It may be concluded that the mono-phased, mesoporous structure is a key feature behind the improved performance over the other electrodes. Further, improvement in charge-discharge characteristics has been observed by a factor of 200% at 60 �C attributing to low activation energy and faster ion dynamics at elevated temperatures. The impedance spectroscopic analysis reveals a significant reduction in interfacial impedances that leads to a superior capacitance effect compounded with favourable electrolytic charge dynamics. The highest energy density is reported to be 21 Wh/kg with a power density of 1300 W/kg in symmetric configuration. Synergistic effect of the binary system along with unique surface morphology and charge storage followed by intercalation and capacitive mechanism results in enhanced performance of supercapacitor with MoS2@15%TiO2. Thus, binary MoS2@TiO2 composite seems to be an exceptional candidate for the energy storage device operating at a wide temperature range (25�60 �C). � 2021 Elsevier B.V.
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    Efficient MoS2/V2O5 Electrocatalyst for Enhanced Oxygen and Hydrogen Evolution Reactions
    (Springer, 2023-04-29T00:00:00) Haldar, Krishna Kanta; Ahmed, Imtiaz; Biswas, Rathindranath; Mete, Shouvik; Patil, Ranjit A.; Ma, Yuan-Ron
    Electrochemical (EC) water splitting is a promising approach for the generation of renewable hydrogen (H2) fuels and oxygen (O2) evolution. Composite structured molybdenum disulphide (MoS2)/vanadium pentoxide (V2O5) with low overpotential is a promising electrocatalyst for anodic and cathodic material for an alternative energy source. We fabricated a flower shape MoS2/V2O5 composite via a hydrothermal approach where V2O5grew on the surface of the MoS2 petals. The unique flower-type composite structure alleviates the surface expansion of electrode material. The electrochemical studies show that the composite possesses good stability with low overpotential and smaller Tafel slope compared to its constituents. It has been found that the MoS2/V2O5 composite exhibits a stable rate performance under the current density of 10�mA�cm?2 which indicates that the MoS2/V2O5 composite might be a good candidate for both oxygen and hydrogen evolution reactions.; Graphical Abstract: [Figure not available: see fulltext.] � 2023, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.
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    NiS/MoS2 Anchored Multiwall Carbon Nanotube Electrocatalyst for Hydrogen Generation and Energy Storage Applications
    (John Wiley and Sons Inc, 2023-04-05T00:00:00) Ahmed, Imtiaz; Biswas, Rathindranath; Iqbal, Muzahir; Roy, Ayan; Haldar, Krishna Kanta
    Although sulfide-based materials are known to be efficient catalysts for oxygen evolution reactions (OER), hydrogen evolution reactions (HER), and supercapacitor applications, improving the catalytic activity of sulfide materials for both electrochemical water splitting and supercapacitors remains a challenging problem. Here, an easy and one-step integrated methodology is implemented to develop NiS/MoS2 anchored multiwall carbon nanotubes (MWCNT/NiS/MoS2) catalysts that can effectively and robustly catalyze both the HER and OER. The MWCNT/NiS/MoS2 hybrid composite offers the lowest overpotential of 201 mV and 193 mV to achieve a current density of 10 mA/cm2 and ?10 mA/cm2 with a small Tafel slope of 58 mV/dec 41 mV/dec for OER and HER, respectively, in alkaline and acidic conditions. The obtained multi-walled carbon nanotubes anchored with intertwined NiS/MoS2 have a significant number of active sites and defects throughout the structure. The hybrid composite electrode delivered a specific capacitance of >371.45 F/g at 2 A/g in a two-electrode system, along with high energy density of 51.63 Wh/kg (ED) along with the power density (PD) of 953.63 W/kg, and good capacitance retention ?82% after 2000 cycles. Therefore, a tandem electron transfer mechanism between NiS and MoS2 (MoS2?NiS) is believed to have an electrical synergistic effect that promotes both HER and OER activity. This research opens a new path for the construction of multi-component, cheap electrocatalysts that are highly effective for overall water splitting and energy storage applications. � 2023 Wiley-VCH GmbH.