Publications by authors named "Sangeetha Kumaravel"

Water electrolysis encounters a challenging problem in designing a highly efficient, long durable, non-noble metal-free electrocatalyst for both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). Here, in our work, a two-step hydrothermal reaction was performed to construct a hierarchal NiFe-layer double hydroxide (LDH)/CuS over copper foam for the overall water splitting reaction. While employed the same as an anode material, the designed heterostructure electrode NiFe-LDH/CuS/Cu exhibits excellent OER performance and it demands 249 mV overpotential to reach a current density of 50 mA cm with a lower Tafel slope value of 81.

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The poor kinetic background with the four-electron transfer of the oxygen evolution reaction (OER) was eradicated using a nickel-based catalyst, which was identified as an alternative to noble-metal catalysts. Here, we report the simple formation of an earth-abundant nickel oxyhydroxide (NiOOH) electrocatalyst for efficient OER in an alkaline medium. Electroless material preparation, namely, the direct modification of a gas diffusion layer (GDL) with a nickel salt, was studied, and the layered oxyhydroxide phase was found to influence the rate of the OER.

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Article Synopsis
  • - The study investigates a new bimetallic zeolite imidazolate framework (ZIF) made of cobalt and manganese to enhance electrocatalytic oxygen evolution reactions (OER) through electrospinning.
  • - The resulting nanofibers exhibited a reduced overpotential of 302 mV at 10 mA/cm² in alkaline conditions, with a Tafel slope of 125 mV/dec and a charge-transfer resistance of 4 Ω, indicating efficient kinetics in the OER process.
  • - It was found that manganese acts as the primary active center in the ZIF-67 nanofibers, while the presence of cobalt affects the Jahn-Teller distortion and overall performance, supported by
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The development of efficient electrocatalysts for the water splitting process and understanding their fundamental catalytic mechanisms are highly essential to achieving high performance in energy conversion technologies. Herein, we have synthesised spinel nickel ferrite nanofibers (NiFeO-NFs) an electrospinning (ES) method followed by a carbonization process. The resultant fiber was subjected to electrocatalytic water splitting reactions in alkaline medium.

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Internal Ni-vacancy-enriched spherical AuNi nanoalloys (AuNi-T) have been prepared via a noble electrochemical etching method. AuNi-T showed the highest oxygen evolution reaction (OER) activity compared to bare AuNi, and it demands only 239 mV overpotential, which was 134 mV lesser than the overpotential required by commercial RuO at 10 mA cm current density in a 1 M KOH solution (pH = 14). The calculated turnover frequency (TOF) value for AuNi-T (0.

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Vast attention from researchers is being given to the development of suitable oxygen evolution reaction (OER) electrocatalysts water electrolysis. Being highly abundant, the use of transition-metal-based OER catalysts has been attractive more recently. Among the various transition-metal-based electrocatalysts, the use of layered double hydroxides (LDHs) has gained special attention from researchers owing to their high stability under OER conditions.

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The generation of pure H from a neutral electrolyte solution represents a transformative route with low cost and environmentally friendly nature. However, the complex kinetics of hydrogen evolution reaction (HER) via water electrolysis make its practical application to be difficult. Herein, we have reported Ru-doping-induced formation of VS nanostructures with a rich S vacancy for neutral HER in a 0.

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Electrocatalytic water splitting has gained vast attention in recent decades for its role in catalyzing hydrogen production effectively as an alternative to fossil fuels. Moreover, the designing of highly efficient oxygen evolution reaction (OER) electrocatalysts across the universal pH conditions was more challengeable as in harsh anodic potentials, it questions the activity and stability of the concerned catalyst. Generally, geometrical engineering and electronic structural modulation of the catalyst can effectively boost the OER activity.

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Development of a low-cost transition metal-based catalyst for water splitting is of prime importance for generating green hydrogen on an industrial scale. Recently, various transition metal-based oxides, hydroxides, sulfides, and other chalcogenide-based materials have been synthesized for developing a suitable anode material for the oxygen evolution reaction (OER). Among the various transition metal-based catalysts, their oxides have received much consideration for OER, especially in lower pH condition, and MnO is one of the oxides that have widely been used for the same.

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The replacement of noble metals with alternative electrocatalysts is highly demanded for water splitting. From the exploration of 3D -transition metal based heterostructures, engineering at the nano-level brought more enhancements in active sites with reduced overpotentials for both the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). However, recent developments in 3D transition metal based heterostructures like direct growth on external substrates (Ni foam, Cu foam) gave highly impressive activities and stabilities.

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The development of a highly efficient electrocatalyst for the oxygen evolution reaction (OER) with a lower overpotential and high intrinsic activity is highly challenging owing to its sluggish kinetic behavior. As an alternative to the state-of-the-art OER catalyst, recently, transition-metal-based hydroxide materials have been shown to play important roles for the same. Owing to the high earth abundance of various Ni-based hydroxide and its derivatives, these are known to be highly studied materials for the OER.

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Direct methanol fuel cell technology implementation mainly depends on the development of non-platinum catalysts with good CO tolerance. Among the widely studied transition-metal catalysts, cobalt oxide with distinctively higher catalytic efficiency is highly desirable. Here, we have evolved a simple method of synthesizing cobalt tungsten oxide hydroxide hydrate nanowires with DNA (CTOOH/DNA) and without incorporating DNA (CTOOH) by microwave irradiation and subsequently employed them as electrocatalysts for methanol oxidation.

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Developing non-noble, earth-ample, and stable electrocatalysts are highly anticipated in oxygen-evolution reaction (OER) and hydrogen-evolution reaction (HER) at unique pH conditions. Herein, we have synthesized bimetallic (nickel and iron) zeolite imidazolate framework (ZIF)-based nanofibrous materials via a simple electrospinning (ES) process. The structural stability of the fibrous material is subjected to various calcination conditions.

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Metal-organic framework (MOF)-based materials have attracted attention in recent times owing to their remarkable properties such as regulatable pore size, high specific surface area, and elasticity in their network topology, geometry, dimension, and chemical functionality. It is believed that the incorporation of a MOF network into a fibrous matrix results in the improvement of the electrocatalytic properties of the material. Herein, we have synthesized a Co-incorporated MOF-5-based fibrous material by a simple wet-chemical method, followed by an electrospinning (ES) process.

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The use of nanomaterials (NMs) in various applications via multidisciplinary approaches is highly necessary in this era. In this line, the impact of noble metals in organic media for both catalysis and surface-enhanced Raman spectroscopic (SERS) studies is most interesting and also has a wider scope in various fields. Nonetheless, the catalytic reduction of aromatic nitro compounds is difficult with poor solubility in aqueous media, and reduction also is less feasible in the absence of noble metal-based catalysts.

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Surface Enhanced Raman Scattering (SERS) is a field of research that has shown promising application in the analysis of various substrate molecules by means of rough metallic surfaces. In directing the enhancement of substrate molecules in micro and nano-molar concentrations, plasmonic coupling of metal nanoparticles (NPs), morphology of metal NPs and the closely arrangement of rough metal surfaces that produces 'hot spots' can effectively increase the so-called enhancement factor (EF) that will be applicable in various fields. As the mechanistic aspects are still not clear, research has been triggered all over the world for the past two decades to have a clear understanding in chemical and electromagnetic effects.

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Out of various available methods, generation of hydrogen by electrocatalytic water splitting is the most accepted one which consists of two half-cell reactions, , oxygen evolution reaction (OER) at the anode and hydrogen evolution reaction at the cathode. OER is a complex four-electron transfer process, and to sustain the spontaneous generation of hydrogen at the cathode, it is urgent to develop some earth-abundant, low-cost electrode materials. Recently, use of cobalt-based hydroxide as the electrode substrate has taken much consideration and has been fabricated over various substrates.

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Production of hydrogen by water electrolysis is an environment-friendly method and comparatively greener than other methods of hydrogen production such as stream reforming carbon, hydrolysis of metal hydride, etc. However, sluggish kinetics of the individual half-cell reactions hinders the large-scale production of hydrogen. To minimize this disadvantage, finding an appropriate, competent, and low-cost catalyst has attracted attention worldwide.

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Depolymerization of lignin biomass to its value-added chemicals and fuels is pivotal for achieving the goals for sustainable society, and therefore has acquired key interest among the researchers worldwide. A number of distinct approaches have evolved in literature for the deconstruction of lignin framework to its mixture of complex constituents in recent decades. Among the existing practices, special attention has been devoted for robust site selective chemical transformation in the complex structural frameworks of lignin.

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An advanced approach with DNA-mediated bismuth tungstate (BiWO) one-dimensional (1-D) nanochain assemblies for hydrogen production with 5-fold enhanced photoelectrochemical (PEC) water splitting reaction is presented. The creation of new surface states upon DNA modification mediates the electron transfer in a facile manner for a better PEC process. The UV-Vis-DRS analysis results a red shift in the optical absorption phenomenon with the interference of DNA modification on BiWO, and, thus, the band gap was tuned from 3.

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The biomolecule DNA with the presence of different functionalities found to interact with different kinds of metal ions and show relatively higher stability over a long period of time when optimized appropriately. With the presence of A-T and G-C pairs, sugar moieties, phosphate functional groups and the double-helical structure, it can assemble both cationic and anionic species and forms a perfect metal-DNA self-assembly. Depending upon the aspect ratio of metal-DNA self-assemblies, metal content and their morphological outcomes, they could deliver variance in the catalytic activities.

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Highly efficient and earth-abundant elements capable of water reduction by electrocatalysis and are attractive for the sustainable generation of fuels. Among the earth-abundant metals, copper is one of the cheapest but often the most neglected choice for the hydrogen evolution reaction (HER) due to its high overvoltage. Herein, for the first time we have tuned the overpotential of copper by tellurizing it by two different methodologies, viz.

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Zeolite imidazolate frameworks (ZIFs) are a subclass of metal organic frameworks (MOFs) and have been considered as a special finding in the current platform of the research arena. ZIFs have been comprised of metal ions with imidazolate linkers. In recent times, ZIFs have been predominately utilized for various applications.

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A material with interdisciplinary properties is of wide interest for use in environmental applications. Currently, hydrogen generation by electrolysis and formation of carbonyl derivatives from alcohols are two different fields that focus on energy and environmental applications. In this work, a new material, Cobalt Tungsten Oxide Hydroxide Hydrate (CTOHH) on deoxyribonucleic acid (DNA) scaffold having chain-like morphology has been prepared for the first time by a facile microwave heating method.

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One-dimensional (1D) based carbonaceous materials have wider applicability owing to flexibility over their properties. Electrospinning is one of the pioneering techniques that is being utilized predominantly for the synthesis of fibers. Fibrous material has their own advantages like, high porosity over its surface, mechanical stability and fascinating physicochemical properties.

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