Department Of Chemistry

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Author: search.filters.author.Roy, Ayan

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    Bifunctional electrochemical OER and HER activity of Ta2O5 nanoparticles over Fe2O3 nanoparticles
    (Royal Society of Chemistry, 2023-08-23T00:00:00) Ahmed, Imtiaz; Burman, Vishal; Biswas, Rathindranath; Roy, Ayan; Sharma, Rohit; Haldar, Krishna Kanta
    Hydrogen production via electrocatalytic water splitting offers encouraging innovations for sustainable and clean energy production as an alternative to conventional energy sources. The improvement of extraordinarily dynamic electrocatalysts is of great interest for work on the performance of gas generation, which is firmly blocked due to the sluggish kinetics of the oxygen evolution reaction (OER). The development of highly efficient base metal catalysts for electrochemical hydrogen and oxygen evolution reactions (HER and OER) is a challenging and promising task. In the present work, a particle over particles of Fe2O3 and Ta2O5 was successfully produced by hydrothermal treatment. The prepared composite shows promising catalytic performance when used as an electrochemical catalyst for OER and HER in alkaline and acidic electrolytes with low overpotentials of 231 and 201 mV at 10 mV cm?2, small Tafel slopes of 71 and 135 mV dec?1, respectively, and good stability properties. The calculated electrochemical surface area (ECSA) for composites is five times higher than that of the original oxides. The result of the OER is significantly better than that of commercial IrO2 catalysts and offers a promising direction for the development of water-splitting catalysts. � 2023 The Royal Society of Chemistry.
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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.