Department Of Physics

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Author: search.filters.author.Biswas, RathindranathHas files: No

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    Unraveling the Role of Orbital Interaction in the Electrochemical HER of the Trimetallic AgAuCu Nanobowl Catalyst
    (American Chemical Society, 2023-03-24T00:00:00) Biswas, Rathindranath; Dastider, Saptarshi Ghosh; Ahmed, Imtiaz; Barua, Sourabh; Mondal, Krishnakanta; Haldar, Krishna Kanta
    Unraveling the origins of the electrocatalytic activity of composite nanomaterials is crucial but inherently challenging. Here, we present a comprehensive investigation of the influence of different orbitals� interaction in the AuAgCu nanobowl model electrocatalyst during the hydrogen evolution reaction (HER). According to our theoretical study, AgAuCu exhibits a lower energy barrier than AgAu and AgCu bimetallic systems for the HER, suggesting that the trimetallic AgAuCu system interacts optimally with H*, resulting in the most efficient HER catalyst. As we delve deeper into the HER activity of AgAuCu, it was observed that the presence of Cu allows Au to adsorb the H* intermediate through the hybridization of s orbitals of hydrogen and s, dx2-y2, and dz2 orbitals of Au. Such orbital interaction was not present in the cases of AgAu and AgCu bimetallic systems, and as a result, these bimetallic systems exhibit lower HER activities. � 2023 American Chemical Society.
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    Reduced graphene oxide doped tellurium nanotubes for high performance supercapacitor
    (Frontiers Media S.A., 2022-10-20T00:00:00) Rani, Pinki; Alegaonkar, Ashwini P.; Biswas, Rathindranath; Jewariya, Yogesh; Kanta Haldar, Krishna; Alegaonkar, Prashant S.
    Supercapacitors have been achieving great interest in energy storage systems for the past couple of decades. Such devices with superior performance, mainly, depending on the material architecture of the electrodes. We report on the preparation of Tellurium nanotubes (Te-tubes diameter ?100�nm and length ?700�nm), with variable doping of conducting network reduced graphene oxide (rGO) to fabricate high-performance electrode characteristics of rGO @ Te. The prepared material was characterized using XRD, FTIR, FESEM, and Raman spectroscopy techniques, including Brunauer-Emmett-Teller, Barrett-Joyner-Halenda measurements. FTIR study revealed that 15% rGO @ Te has a wide C-O vibration band at ? 1,100�1,300�cm?1, over other compositions. FESEM study shows the Te-tubes dispersion in rGO layers. The EDX study revealed that 15% of the composition has an optimistic concentration of C and O elements. In other compositions, either at lower/higher rGO concentration, an uneven count of C and O is observed. These support efficient charge dynamics to achieve superior ultra-capacitor characteristics, thereby achieving specific capacitance Csp 170 + F/g @ 10�mV/s in a symmetric configuration. The reported values are thirty times higher than pristine Te-tubes (?5�F/g). This finding suggests that rGO @ Te is a promising candidate for supercapacitor. Copyright � 2022 Rani, Alegaonkar, Biswas, Jewariya, Kanta Haldar and Alegaonkar.
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    LaCoO3Perovskite Nanoparticles Embedded in NiCo2O4Nanoflowers as Electrocatalysts for Oxygen Evolution
    (American Chemical Society, 2022-11-08T00:00:00) Kubba, Deeksha; Ahmed, Imtiaz; Kour, Pawanpreet; Biswas, Rathindranath; Kaur, Harpreet; Yadav, Kamlesh; Haldar, Krishna Kanta
    It is essential to design high-efficiency, stable, and inexpensive electrocatalysts for the oxygen evolution reaction (OER). We fabricate a hybrid system of perovskite LaCoO3 with spinel NiCo2O4 denoted LaCoO3/NiCo2O4 via an in situ hydrothermal process. In situ incorporation of LaCoO3 nanoparticles on the NiCo2O4 nanoflower surface is confirmed by field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) images. Benefiting from the interface engineering, the obtained LaCoO3/NiCo2O4 hybrid nanoflowers exhibit the lowest overpotential of 353 at a current density of 10 mA/cm2 and a small Tafel slope of 59 mV/dec in alkaline media compared with pristine LaCoO3 (401 mV, 116 mV/dec) and NiCo2O4 (386 mV, 73 mV/dec). The optimized sample possesses a higher electrochemical surface of 111.45 cm2 than LaCoO3 perovskite (35.37 cm2) and NiCo2O4 spinel oxide (61.37 cm2) structures. The enhanced OER performance of the LaCoO3/NiCo2O4 composite structure is due to the accumulation of LaCoO3 nanoparticles over NiCo2O4 petals, which introduces a substantial number of electrochemically active sites for the catalysis process to promote charge and mass transport. In addition to this, LaCoO3/NiCo2O4 exhibits long-term stability over 20 h. Thus, it is believed that the excellent OER activity of the LaCoO3/NiCo2O4 composite structure is associated with strong interaction between LaCoO3 and NiCo2O4 as well as a large surface area and a unique flower structure. � 2022 American Chemical Society.