Publications by authors named "Sirshendu Ghosh"

Electro-valorization of biomass-derived chemicals has ensured sustainable production of value-added products, an effective approach for reducing carbon footprint, through renewable energy. Electrochemical oxidation and reduction reactions in aqueous media using HO as a potential source for active hydrogenated and oxygenated species fulfill the purpose. In this study, Ru─CoP nanorods are explored as a bifunctional electrocatalyst toward valorization of Organics at basic media.

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Bifunctional electrocatalysts for efficient hydrogen generation from water splitting must overcome both the sluggish water dissociation step of the alkaline hydrogen evolution half-reaction (HER) and the kinetic barrier of the anodic oxygen evolution half-reaction (OER). Nickel phosphides are a promising catalysts family and are known to develop a thin active layer of oxidized Ni in an alkaline medium. Here, NiP was recognized as a suitable platform for the electrochemical production of γ-NiOOH─a particularly active phase─because of its matching crystallographic structure.

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Article Synopsis
  • SnS and SnS are layered semiconductors that show promise for hydrogen production but haven't been fully optimized until now.
  • This study presents the first successful structural transformation of SnS into Mo-doped SnS, enhancing its catalytic properties for hydrogen evolution.
  • The modified Mo-SnS demonstrated significant improvements, achieving a lower overpotential of 377 mV for the hydrogen evolution reaction and producing hydrogen at a rate that's 20 times greater than the original SnS under visible light.
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Bright white light emission (CIE values 0.32 and 0.33) has been achieved by a single excitation source (254 nm) from a monodispersed nanocomposite composed of Ce3+, Tb3+ and Sm3+ doped LaF3 nanocrystals (NCs) and N-doped C-dots where Ce3+ acts as an excellent sensitizer.

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Tetravalent Sn doped ZnO nanocrystals show excellent plasmonic absorbance in the visible region. Plasmonic ZnS@Sn:ZnO core-shell heterostructures have been synthesized by the anion exchange process where the O is exchanged by S anion. An increase of sulfur concentration induces interior hollow structures arising from the different diffusion rates of O and S ions.

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Three different types of fluorescent gold clusters (namely blue, green and red emitting) have been prepared from a gold precursor (chloroauric acid) under moderate conditions in aqueous medium. A cysteine containing dipeptide has been used for the formation of these quantum clusters as this peptide molecule contains a thiol group in the side chain to cap these nascently formed clusters and the free amino and carboxylic moieties assist in water solubility. Thus, the clusters are also environmentally friendly as the capped peptide is made up of only naturally occurring protein amino acids.

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The synthesis of different anisotropic shaped (eight different shapes) Sn doped CdO (Sn:CdO) colloidal nanocrystals (NCs) by precise tuning of precursor reactivity and proper choice of capping agent is reported. In all these systems, formation of Sn:CdO quantum dots (QDs) of 2-3 nm is identified at very early stage of reaction. The colloidally stable QDs act as a continuous source for the formation of primary nanoparticles that can be transformed selectively into specific type of nanoparticle morphology.

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Understanding the effect of homovalent cation alloying in wide band gap ZnO and the formation of metal-semiconductor heterostructures is very important for maximisation of the photophysical properties of ZnO. Nearly monodisperse ZnO nanopyramid and Mg alloyed ZnO nanostructures have been successfully synthesized by one pot decomposition of metal stearate by using oleylamine both as activating and capping agent. The solid solubility of Mg(ii) ions in ZnO is limited to ∼30% without phase segregation.

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Indium sulphide (In2S3) quantum dots (QDs) of average size 6 ± 2 nm and hexagonal nanoplatelets of average size 37 ± 4 nm have been synthesized from indium myristate and indium diethyl dithiocarbamate precursors respectively. The absorbance and emission band was tuned with variation of nanocrytal size from very small in the strong confinement regime to very large in the weak confinement regime. The blue emission and its shifting with size has been explained with the donor-acceptor recombination process.

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High quality nearly monodisperse colloidal WO3-x nanorods with an aspect ratio ∼18 were synthesized using the thermal decomposition technique. The effects of a capping agent and an activating agent on the nanorod aspect ratio have been studied. Excess carrier concentration due to large oxygen vacancy and smaller width of the nanorods compared to the Bohr exciton radius gives rise to an increase of the band gap.

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Colloidal trivalent gallium (Ga) doped zinc oxide (ZnO) hexagonal nanocrystals have been prepared to introduce more carrier concentration into the wide band gap of ZnO. The dopant (Ga) modifies the morphology and size of ZnO nanocrystals. Low content of Ga enhances the optical band gap of ZnO due to excess carrier concentration in the conduction band of ZnO.

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Article Synopsis
  • * Doping with 8% indium changes the structure from hexagonal pyramids to a platelet form and introduces free electrons, creating plasmonic resonance in the infrared region, which is influenced by the concentration of electrons and alters the band gap of the ZnO.
  • * The resulting nanocrystals are highly stable, allowing for the creation of conductive thin films with strong plasmonic absorption and high visible light transmittance. Additionally, a temperature-induced metal-semiconductor transition occurs, which
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Oleic acid capped monodisperse SnO(2) quantum dots (QDs) of size 2.7 nm were synthesized by thermal decomposition and oxidation of Sn(II)(oleate) complex in high boiling nonpolar solvent octadecene using oleic acid as a capping agent and N-methylmorpholine N-oxide as an oxidizing agent. FTIR, DSC and TGA were employed to understand the growth of the oleic acid capped SnO(2) QDs through the decomposition of metal fatty acid complex.

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