School Of Basic And Applied Sciences

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Author: search.filters.author.Biswas, RathindranathSubject: search.filters.subject.Composite

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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.
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    One pot synthesis of Au embedded ZnO nanorods composite heterostructures with excellent photocatalytic properties
    (Central University of Punjab, 2018) Biswas, Rathindranath; Haldar, Krishna Kanta
    Here, we have designed a noble composite nanostructure by embedding Au nanoparticles into ZnO nanorods surface in one pot synthesis as a photocatalyst. The formation the composite nanostructure was confirmed by X-ray diffraction, Xray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) investigations. Microscopic studies suggest that spherical Au nanoparticles are nucleated on the ZnO nanorods surface. XPS shows shifting of peak positions towards higher binding energy indicating charge transfer from ZnO to Au in the composite nanostructures. This is unambiguously confirmed by the steady state spectroscopic studies. It is found that 95.7% of Methylene blue (MB) dye is degraded by the composite nanostructure after 140 min under UV light illumination, and the apparent rate constant is found to be 0.013 min-1 . This new class of Au nanoparticles embedded ZnO nanorods composite nanostructure opens up new possibilities in photocatalytic, solar energy conversion, photovoltaic, and other new emerging applications.