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Papers by Vishal Rimal

12th International Conference of Molten Slags, Fluxes and Salts (MOLTEN 2024) Proceedings, Jun 19, 2024

Multiphase slags form the basis of the reduction pathway for manganese ferroalloy production. The... more Multiphase slags form the basis of the reduction pathway for manganese ferroalloy production. The present work aims to understand the flow of slag through the coke bed based on experimentation in controlled conditions. Synthetic slags of different basicities were evaluated for their phase composition, viscosity, and flow. The two-phase slag will have two zones: a liquid slag zone and a multiphase zone. The multiphase zone will consist mostly of a solid phase with some liquid slag between the solid particles. The multiphase part will hence have a high viscosity. The liquid zone will flow into the coke bed while the multiphase area will stay. With increasing reduction, the multiphase area will decrease in size until the solid phase is gone and the whole slag will flow into the coke bed. The effective viscosity of slag will decrease with the lowering of the solid oxide phase. The results from flow experiments confirmed that the segregation of phases occurs when slag flows through the coke bed. It is observed that the flow is dependent both on the size of the void and the viscosity of slag.

Fullerenes, Nanotubes and Carbon Nanostructures

Hydrogen evolution reaction (HER) is of high priority at present. Existing research has involved ... more Hydrogen evolution reaction (HER) is of high priority at present. Existing research has involved the use of noble metals as catalysts for HER, thus putting an urgency to develop low-cost materials to replace them. In this work, metal-free Oleic acid functionalized Carbon Dots have been for the first time reported to have outstanding activity for HER. Electrochemical investigation reveals excellent catalytic performance with overpotential of 1 mV at a current density of-5 mA cm −2. The performance at this range marks a significant milestone and paves the way for a sustainable future of metal-free catalysis.

Materials Today: Proceedings, 2022

Carbon Dots (CDs) are zero-dimensional carbon nanomaterials that can be doped with N, S, P, and B... more Carbon Dots (CDs) are zero-dimensional carbon nanomaterials that can be doped with N, S, P, and B heteroatoms to boost their properties. CDs have attracted significant interest over the past decade due to their outstanding physicochemical properties, which are complemented by their low cost, green chemistry, and excellent stability. The combination of CDs with traditional electrochemical materials has been found to alter the kinetics of electrochemical reactions. This review aims to underline the notable results on the electrochemical kinetics of CDs. The advances in this domain would promote the development of fuel cells, water electrolysis, and rechargeable metal-air batteries and pave new directions on the applicability of CDs.

Materials Today: Proceedings, 2022

Carbon Dots (CDs) have garnered special consideration from researchers due to their unique proper... more Carbon Dots (CDs) have garnered special consideration from researchers due to their unique properties, inexpensive cost, easy synthesis, and functionalization. Over the years, CDs have been synthesized from various plant-based precursors like stems, roots, leaves, fruits, seeds, and oils. In the present manuscript, CDs were synthesized from essential oil. The synthesis involved the use of bottom-up green pyrolysis method without using any additional reagents. The CDs were characterized using UV-Visible, Fluorescence, and FT-IR spectroscopy. Anticipated inferences and properties were observed in the study. The manuscript also underlines the imminent trends and directions in the applicability of CDs.

IOP Conference Series: Materials Science and Engineering, 2022

Carbon Dots (CDs) in the recent years have been found to exhibit exceptional thermal stability. T... more Carbon Dots (CDs) in the recent years have been found to exhibit exceptional thermal stability. The superior nature CDs demonstrate in their physical, chemical, optical and conductive properties together with their low cytotoxicity make them a true contender to conventional inorganic counterparts. In this study the traditional thermodynamic properties that support the high thermal stability of CDs have been investigated. The thermal stability of CDs has been found to have a superior relationship with numerous parameters thereby paving a strong evidence for further research and advancement in the field. This result will further help in the development of organic nanoparticles which can be employed in environments where high-temperature resistance is a crucial requirement.

Applied Nanoscience, 2021

In the present research oleic acid carbon dots have been optimized for high-thermal stability app... more In the present research oleic acid carbon dots have been optimized for high-thermal stability applications via suitable thermal-tuning in liquid as well as in anhydrous medium. The intended tuning of the nano-dimensional particles was achieved by Fischer Esterification using suitable hydroxyl group-bearing moieties. The achieved external surface functionalization was fast, easy and cost-effective. The synthesized carbon dots were characterized using UV-Vis, Fluorescence, FT-IR, SEM, TGA and DSC techniques. The coalesce of the stated instrumentations derived a possible mechanistic approach and relationship regarding the thermal-tuning of the carbon dots for a deeper overview. The band-gap energy measurement revealed exclusive wide band-gap semiconductor characteristics of the investigated nanoparticles. Further, the fabrication of carbon dots on cotton fabric potentialized a new class of synthetic flame-retardant free high temperature resistant textiles, deemed essential for a greener future. The enhanced nature of these carbon dots with requisite alteration capabilities for temperatures as high as 800 °C could certainly improve the applicability of these particles in future electronic advancements.

Applied Nanoscience, 2021

In the present study Carbon Dots (CDs) derived from Indian essential oils Clove (Eugenia caryophy... more In the present study Carbon Dots (CDs) derived from Indian essential oils Clove (Eugenia caryophyllata), Basil (Ocimum basilicium), Turmeric (Curcuma longa) and Cardamom (Elettaria cardamomum) have been synthesized and characterized for their potential exquisite applications. The CD nanoscale particles were synthesized using simple green pyrolysis method without engaging external agents. The particles were well below 10 nm in size and showed activities unparallel to that of conventional CDs. Spectroscopy techniques viz. UV-Visible, Fluorescence, FT-IR, TEM were employed for the characterization of CDs while biological activity was tested on sliced bread and spinach (Spinacia oleracea). Further, human MCF-7 cell line was used to study the antiproliferative effects of the CDs in vitro. Our CDs formulation exhibit variable fungal activity and excellent growth retarding potential in addition to their antiproliferative effect. The low cost, ease of synthesis and superior properties of these CDs synthesized from Indian essential oils may represent as a viable and true contender to their traditional counterparts. On a concluding note, this work also highlights the future prospects of the potential use of CDs based nanoparticles and their unpopular characteristics.

Applied Nanoscience, 2020

Novel high-thermal stability photoluminescent carbon dots (CDs) with a quantum yield of 50% in wa... more Novel high-thermal stability photoluminescent carbon dots (CDs) with a quantum yield of 50% in water were synthesized using oleic acid as an organic substrate. The synthesized CDs were of the order of 10 nm and exhibit bright green luminescence in the UV spectrum. The nanoparticles possessed analogous physical, chemical, optical and conductive properties in addition to their low cytotoxicity. The surface area and size effect potentialize the CDs for optical and electrical applications. The nanoparticles were also hosted in a cellulose acetate polymer matrix to form a polymer nanocomposite. The CDs and the CD–polymer nanocomposite were characterized by Zeta and particle size analyzer, UV–visible spectroscopy, fluorescence spectroscopy, SEM, XRD, FTIR, TGA and DSC. The CDs were examined and found to exhibit excellent thermal stability within 800 °C. This result paves way for the study of a new class of organic nanoparticles which can be utilized in high-temperature environments.

Thesis Chapters by Vishal Rimal

Hydrogen evolution reaction (HER) is of high priority at present. Existing research has involved ... more Hydrogen evolution reaction (HER) is of high priority at present. Existing research has involved the use of noble metals as catalysts for HER, thus putting an urgency to develop low-cost materials to replace them. Carbon dots (CDs) are a type of carbon nanomaterial with excellent potential for applications in catalysis. The main motivation for this research was to produce efficient metal-free carbon based electrocatalysts for HER. CDs were synthesized from oleic acid using bottom-up approach and functionalized with elements influencing their electrochemical kinetics. Optical, imaging, and electrochemical characterization was performed to understand the electrocatalytic performance. Mechanistic insights on the formation of CDs were inferred from the spectroscopic characterization. Likewise imaging data delivered a suitable link between morphology, and the catalytic performance. Electrochemical investigation demonstrated excellent electrocatalytic performance with an overpotential at 0.001 VRHE at a current density of-5 mA cm−2. The performance at this range marks a significant milestone and this thesis project paves way for a sustainable future of low-cost efficient metal-free catalysis.

12th International Conference of Molten Slags, Fluxes and Salts (MOLTEN 2024) Proceedings, Jun 19, 2024

Multiphase slags form the basis of the reduction pathway for manganese ferroalloy production. The... more Multiphase slags form the basis of the reduction pathway for manganese ferroalloy production. The present work aims to understand the flow of slag through the coke bed based on experimentation in controlled conditions. Synthetic slags of different basicities were evaluated for their phase composition, viscosity, and flow. The two-phase slag will have two zones: a liquid slag zone and a multiphase zone. The multiphase zone will consist mostly of a solid phase with some liquid slag between the solid particles. The multiphase part will hence have a high viscosity. The liquid zone will flow into the coke bed while the multiphase area will stay. With increasing reduction, the multiphase area will decrease in size until the solid phase is gone and the whole slag will flow into the coke bed. The effective viscosity of slag will decrease with the lowering of the solid oxide phase. The results from flow experiments confirmed that the segregation of phases occurs when slag flows through the coke bed. It is observed that the flow is dependent both on the size of the void and the viscosity of slag.

Fullerenes, Nanotubes and Carbon Nanostructures

Hydrogen evolution reaction (HER) is of high priority at present. Existing research has involved ... more Hydrogen evolution reaction (HER) is of high priority at present. Existing research has involved the use of noble metals as catalysts for HER, thus putting an urgency to develop low-cost materials to replace them. In this work, metal-free Oleic acid functionalized Carbon Dots have been for the first time reported to have outstanding activity for HER. Electrochemical investigation reveals excellent catalytic performance with overpotential of 1 mV at a current density of-5 mA cm −2. The performance at this range marks a significant milestone and paves the way for a sustainable future of metal-free catalysis.

Materials Today: Proceedings, 2022

Carbon Dots (CDs) are zero-dimensional carbon nanomaterials that can be doped with N, S, P, and B... more Carbon Dots (CDs) are zero-dimensional carbon nanomaterials that can be doped with N, S, P, and B heteroatoms to boost their properties. CDs have attracted significant interest over the past decade due to their outstanding physicochemical properties, which are complemented by their low cost, green chemistry, and excellent stability. The combination of CDs with traditional electrochemical materials has been found to alter the kinetics of electrochemical reactions. This review aims to underline the notable results on the electrochemical kinetics of CDs. The advances in this domain would promote the development of fuel cells, water electrolysis, and rechargeable metal-air batteries and pave new directions on the applicability of CDs.

Materials Today: Proceedings, 2022

Carbon Dots (CDs) have garnered special consideration from researchers due to their unique proper... more Carbon Dots (CDs) have garnered special consideration from researchers due to their unique properties, inexpensive cost, easy synthesis, and functionalization. Over the years, CDs have been synthesized from various plant-based precursors like stems, roots, leaves, fruits, seeds, and oils. In the present manuscript, CDs were synthesized from essential oil. The synthesis involved the use of bottom-up green pyrolysis method without using any additional reagents. The CDs were characterized using UV-Visible, Fluorescence, and FT-IR spectroscopy. Anticipated inferences and properties were observed in the study. The manuscript also underlines the imminent trends and directions in the applicability of CDs.

IOP Conference Series: Materials Science and Engineering, 2022

Carbon Dots (CDs) in the recent years have been found to exhibit exceptional thermal stability. T... more Carbon Dots (CDs) in the recent years have been found to exhibit exceptional thermal stability. The superior nature CDs demonstrate in their physical, chemical, optical and conductive properties together with their low cytotoxicity make them a true contender to conventional inorganic counterparts. In this study the traditional thermodynamic properties that support the high thermal stability of CDs have been investigated. The thermal stability of CDs has been found to have a superior relationship with numerous parameters thereby paving a strong evidence for further research and advancement in the field. This result will further help in the development of organic nanoparticles which can be employed in environments where high-temperature resistance is a crucial requirement.

Applied Nanoscience, 2021

In the present research oleic acid carbon dots have been optimized for high-thermal stability app... more In the present research oleic acid carbon dots have been optimized for high-thermal stability applications via suitable thermal-tuning in liquid as well as in anhydrous medium. The intended tuning of the nano-dimensional particles was achieved by Fischer Esterification using suitable hydroxyl group-bearing moieties. The achieved external surface functionalization was fast, easy and cost-effective. The synthesized carbon dots were characterized using UV-Vis, Fluorescence, FT-IR, SEM, TGA and DSC techniques. The coalesce of the stated instrumentations derived a possible mechanistic approach and relationship regarding the thermal-tuning of the carbon dots for a deeper overview. The band-gap energy measurement revealed exclusive wide band-gap semiconductor characteristics of the investigated nanoparticles. Further, the fabrication of carbon dots on cotton fabric potentialized a new class of synthetic flame-retardant free high temperature resistant textiles, deemed essential for a greener future. The enhanced nature of these carbon dots with requisite alteration capabilities for temperatures as high as 800 °C could certainly improve the applicability of these particles in future electronic advancements.

Applied Nanoscience, 2021

In the present study Carbon Dots (CDs) derived from Indian essential oils Clove (Eugenia caryophy... more In the present study Carbon Dots (CDs) derived from Indian essential oils Clove (Eugenia caryophyllata), Basil (Ocimum basilicium), Turmeric (Curcuma longa) and Cardamom (Elettaria cardamomum) have been synthesized and characterized for their potential exquisite applications. The CD nanoscale particles were synthesized using simple green pyrolysis method without engaging external agents. The particles were well below 10 nm in size and showed activities unparallel to that of conventional CDs. Spectroscopy techniques viz. UV-Visible, Fluorescence, FT-IR, TEM were employed for the characterization of CDs while biological activity was tested on sliced bread and spinach (Spinacia oleracea). Further, human MCF-7 cell line was used to study the antiproliferative effects of the CDs in vitro. Our CDs formulation exhibit variable fungal activity and excellent growth retarding potential in addition to their antiproliferative effect. The low cost, ease of synthesis and superior properties of these CDs synthesized from Indian essential oils may represent as a viable and true contender to their traditional counterparts. On a concluding note, this work also highlights the future prospects of the potential use of CDs based nanoparticles and their unpopular characteristics.

Applied Nanoscience, 2020

Novel high-thermal stability photoluminescent carbon dots (CDs) with a quantum yield of 50% in wa... more Novel high-thermal stability photoluminescent carbon dots (CDs) with a quantum yield of 50% in water were synthesized using oleic acid as an organic substrate. The synthesized CDs were of the order of 10 nm and exhibit bright green luminescence in the UV spectrum. The nanoparticles possessed analogous physical, chemical, optical and conductive properties in addition to their low cytotoxicity. The surface area and size effect potentialize the CDs for optical and electrical applications. The nanoparticles were also hosted in a cellulose acetate polymer matrix to form a polymer nanocomposite. The CDs and the CD–polymer nanocomposite were characterized by Zeta and particle size analyzer, UV–visible spectroscopy, fluorescence spectroscopy, SEM, XRD, FTIR, TGA and DSC. The CDs were examined and found to exhibit excellent thermal stability within 800 °C. This result paves way for the study of a new class of organic nanoparticles which can be utilized in high-temperature environments.

Hydrogen evolution reaction (HER) is of high priority at present. Existing research has involved ... more Hydrogen evolution reaction (HER) is of high priority at present. Existing research has involved the use of noble metals as catalysts for HER, thus putting an urgency to develop low-cost materials to replace them. Carbon dots (CDs) are a type of carbon nanomaterial with excellent potential for applications in catalysis. The main motivation for this research was to produce efficient metal-free carbon based electrocatalysts for HER. CDs were synthesized from oleic acid using bottom-up approach and functionalized with elements influencing their electrochemical kinetics. Optical, imaging, and electrochemical characterization was performed to understand the electrocatalytic performance. Mechanistic insights on the formation of CDs were inferred from the spectroscopic characterization. Likewise imaging data delivered a suitable link between morphology, and the catalytic performance. Electrochemical investigation demonstrated excellent electrocatalytic performance with an overpotential at 0.001 VRHE at a current density of-5 mA cm−2. The performance at this range marks a significant milestone and this thesis project paves way for a sustainable future of low-cost efficient metal-free catalysis.