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Electrochemical unzipping of multi-walled carbon nanotubes for facile synthesis of high-quality graphene nanoribbons 总被引:1,自引:0,他引:1
Shinde DB Debgupta J Kushwaha A Aslam M Pillai VK 《Journal of the American Chemical Society》2011,133(12):4168-4171
Here we report a remarkable transformation of carbon nanotubes (CNTs) to nanoribbons composed of a few layers of graphene by a two-step electrochemical approach. This consists of the oxidation of CNTs at controlled potential, followed by reduction to form graphene nanoribbons (GNRs) having smooth edges and fewer defects, as evidenced by multiple characterization techniques, including Raman spectroscopy, atomic force microscopy, and transmission electron microscopy. This type of "unzipping" of CNTs (single-walled, multi-walled) in the presence of an interfacial electric field provides unique advantages with respect to the orientation of CNTs, which might make possible the production of GNRs with controlled widths and fewer defects. 相似文献
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Panjo Lepcha Dr. Sachidulal Biswas Srijan Narayan Chowdhury Dr. Suranjana Bose Dr. Joyashish Debgupta Dr. Satadal Paul Dr. Achintesh N. Biswas 《欧洲无机化学杂志》2023,26(7):e202200611
A Co(III)−hydroxo complex, [CoIII(dpaq)OH]ClO4 ( 1-OH ) bearing a pentadentate ligand, H-dpaq, (H-dpaq=(2-[bis(pyridin-2-ylmethyl)]amino-N-quinolin-8-yl-acetamidate]) catalyses water oxidation in mildly alkaline medium (pH 8.0) at a potential of 1.4 VNHE with an average Turn-Over-Frequency (TOFmax) of 2.8×104 s−1 and faradaic efficiency of 88 %. Post-electrolysis characterization of the electrode rules out the formation of any heterogeneous electroactive species. Electrochemical results and theoretical calculations confirm the occurrence of both metal and ligand centered PCET processes during anodic scanning. The resulting formally Co(V)−oxo/oxyl intermediate undergoes water nucleophilic attack to install the O−O bond. The role of axial ligand in water oxidation by Co(III)−dpaq system has been examined by comparing the reactivity of the Co-hydroxide complex ( 1-OH ) with that of its chloride-ligated counterpart, [CoIII(dpaq)Cl]Cl ( 1-Cl ). The results confirm the ability of the Co-dpaq complexes to bind water/or water derived ligands over chloride or non-aqueous solvents. The interplay of ligand redox non-innocence and σ-donating ability of the N5-carboxamido ligand helps to store oxidizing equivalents and triggers O−O bond formation. 相似文献
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Differential wetting of pristine and ozonized carbon nanotubes has been studied using solvents like acetonitrile and dichloromethane in comparison to the well-known wetting behavior of water. Based on their unique structural and physical properties, functionalized CNT substrates have been used due to the fact that independent variation in molecular as well as electronic properties could be controlled by understanding the wetting of these liquids on carbon nanotubes (CNTs), both pristine as well as ozone treated. The sensitivity of the wetting behavior with respect to molecular interactions has been investigated using contact angle measurements while Raman and XPS studies unravel the differential wetting behavior. Charge-transfer between adsorbed molecules and CNTs has been identified to play a crucial role in determining the interfacial energies of these two liquids, especially in the case of acetonitrile. Ozone treatment has been observed to affect the surface properties of pristine CNTs along with a concomitant change in the wetting dynamics. 相似文献
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In situ decoration of very small CdSe quantum dots on graphene nanoribbons (GNRs) has been achieved during the electrochemical unzipping of single walled carbon nanotubes. Critical parameters like the width of the GNRs, size distribution of quantum dots and their organization on GNRs have been shown to be strongly dependent on the electric field and time. 相似文献
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Facile Green Synthesis of BCN Nanosheets as High‐Performance Electrode Material for Electrochemical Energy Storage 下载免费PDF全文
Indrapal Karbhal Rami Reddy Devarapalli Joyashish Debgupta Vijayamohanan K. Pillai Pulickel M. Ajayan Manjusha V. Shelke 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(21):7134-7140
Two‐dimensional hexagonal boron carbon nitride (BCN) nanosheets (NSs) were synthesized by new approach in which a mixture of glucose and an adduct of boric acid (H3BO3) and urea (NH2CONH2) is heated at 900 °C. The method is green, scalable and gives a high yield of BCN NSs with average size of about 1 μm and thickness of about 13 nm. Structural characterization of the as‐synthesized material was carried out by several techniques, and its energy‐storage properties were evaluated electrochemically. The material showed excellent capacitive behaviour with a specific capacitance as high as 244 F g?1 at a current density of 1 A g?1. The material retains up to 96 % of its initial capacity after 3000 cycles at a current density of 5 A g?1. 相似文献
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A Mononuclear CoII Coordination Complex Locked in a Confined Space and Acting as an Electrochemical Water‐Oxidation Catalyst: A “Ship‐in‐a‐Bottle” Approach 下载免费PDF全文
Paulami Manna Dr. Joyashish Debgupta Dr. Suranjana Bose Prof. Samar K. Das 《Angewandte Chemie (International ed. in English)》2016,55(7):2425-2430
Preparing efficient and robust water oxidation catalyst (WOC) with inexpensive materials remains a crucial challenge in artificial photosynthesis and for renewable energy. Existing heterogeneous WOCs are mostly metal oxides/hydroxides immobilized on solid supports. Herein we report a newly synthesized and structurally characterized metal–organic hybrid compound [{Co3(μ3‐OH)(BTB)2(dpe)2} {Co(H2O)4(DMF)2}0.5]n?n H2O ( Co‐WOC‐1 ) as an effective and stable water‐oxidation electrocatalyst in an alkaline medium. In the crystal structure of Co‐WOC‐1 , a mononuclear CoII complex {Co(H2O)4(DMF)2}2+ is encapsulated in the void space of a 3D framework structure and this translationally rigid complex cation is responsible for a remarkable electrocatalytic WO activity, with a catalytic turnover frequency (TOF) of 0.05 s?1 at an overpotential of 390 mV (vs. NHE) in 0.1 m KOH along with prolonged stability. This host–guest system can be described as a “ship‐in‐a‐bottle”, and is a new class of heterogeneous WOC. 相似文献
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A Keggin Polyoxometalate Shows Water Oxidation Activity at Neutral pH: POM@ZIF‐8, an Efficient and Robust Electrocatalyst 下载免费PDF全文
Subhabrata Mukhopadhyay Dr. Joyashish Debgupta Chandani Singh Aranya Kar Prof. Samar K. Das 《Angewandte Chemie (International ed. in English)》2018,57(7):1918-1923
Keggin‐type polyoxometalate anions [XM12O40]n? are versatile, as their applications in interdisciplinary areas show. The Keggin anion [CoW12O40]6? turns into an efficient and robust electrocatalyst upon its confinement in the well‐defined void space of ZIF‐8, a metal–organic framework (MOF). [H6CoW12O40]@ZIF‐8 is so stable to water oxidation that it retains its initial activity even after 1000 catalytic cycles. The catalyst has a turnover frequency (TOF) of 10.8 mol O2(mol Co)?1 s?1, one of the highest TOFs for electrocatalytic oxygen evolution at neutral pH. Controlled experiments rule out the chances of formation and participation of CoOx in this electrocatalyic water oxidation. 相似文献
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