The Experts below are selected from a list of 8739 Experts worldwide ranked by ideXlab platform
Rahul Banerjee - One of the best experts on this subject based on the ideXlab platform.
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Triazine Functionalized Porous Covalent Organic Framework for Photo-organocatalytic E–Z Isomerization of Olefins
2019Co-Authors: Mohitosh Bhadra, Sharath Kandambeth, Manoj K. Sahoo, Matthew Addicoat, Ekambaram Balaraman, Rahul BanerjeeAbstract:Visible light-mediated photocatalytic Organic transformation has drawn significant attention as an alternative process for replacing thermal reactions. Although precious metal/Organic dyes based homogeneous photocatalysts have been developed, their toxic and nonreusable nature makes them inappropriate for large-scale production. Therefore, we have synthesized a triazine and a keto functionalized nonmetal based Covalent Organic Framework (TpTt) for heterogeneous photocatalysis. As the catalyst shows significant absorption of visible light, it has been applied for the photocatalytic uphill conversion of trans-stilbene to cis-stilbene in the presence of blue light-emitting diodes with broad substrate scope via an energy transfer process
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Transforming Covalent Organic Framework into thin-film composite membranes for hydrocarbon recovery
2018Co-Authors: Bishnu P Biswal, Rahul Banerjee, Shebeeb H Kunjattu, Taranpreet Kaur, Ulhas K KharulAbstract:We, for the first time, employed chemically stable Covalent Organic Framework (COF) (TpPa-1) as a transport-active phase within the polymer (styrene-butadiene rubber; SBR) matrix to make TpPa-1@SBR thin-film composite (TFC) membranes. Three composite membranes, viz., TpPa-1(30)@SBR, TpPa-1(50)@SBR, and TpPa-1(70)@SBR have been prepared with varying COF content. These membranes were characterized for gas permeance and results were compared with the pristine SBR-based TFC membrane. The fully Organic nature of chemically stable COF offered good compatibility with the host polymer matrix (SBR) and resulted into flexible TFC membranes even at 70% of COF loading; compared to the other porous material (MOFs or InOrganic fillers), it is appreciable.
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cobalt modified Covalent Organic Framework as a robust water oxidation electrocatalyst
Chemistry of Materials, 2016Co-Authors: Harshitha Barike Aiyappa, Rahul Banerjee, Jayshri Thote, Digambar Balaji Shinde, Sreekumar KurungotAbstract:The development of stable, efficient oxygen evolution reaction (OER) catalyst capable of oxidizing water is one of the premier challenges in the conversion of solar energy to electrical energy, because of its poor kinetics. Herein, a bipyridine-containing Covalent Organic Framework (TpBpy) is utilized as an OER catalyst by way of engineering active Co(II) ions into its porous Framework. The as-obtained Co-TpBpy retains a highly accessible surface area (450 m2/g) with exceptional stability, even after 1000 cycles and 24 h of OER activity in phosphate buffer under neutral pH conditions with an overpotential of 400 mV at a current density of 1 mA/cm2. The unusual catalytic stability of Co-TpBpy arises from the synergetic effect of the inherent porosity and presence of coordinating units in the COF skeleton.
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Self-templated chemically stable hollow spherical Covalent Organic Framework
Nature Communications, 2015Co-Authors: Sharath Kandambeth, V. Venkatesh, Digambar B. Shinde, Sushma Kumari, Arjun Halder, Sandeep Verma, Rahul BanerjeeAbstract:Hollow, spherical nano/microstructures are potentially useful for energy and drug delivery applications. Here, the authors show that these structures can be fabricated from Covalent Organic Frameworks, and exploit their chemical stability and mesoporous structures for enzyme encapsulation. Covalent Organic Frameworks are a family of crystalline porous materials with promising applications. Although active research on the design and synthesis of Covalent Organic Frameworks has been ongoing for almost a decade, the mechanisms of formation of Covalent Organic Frameworks crystallites remain poorly understood. Here we report the synthesis of a hollow spherical Covalent Organic Framework with mesoporous walls in a single-step template-free method. A detailed time-dependent study of hollow sphere formation reveals that an inside-out Ostwald ripening process is responsible for the hollow sphere formation. The synthesized Covalent Organic Framework hollow spheres are highly porous (surface area ∼1,500 m^2g^−1), crystalline and chemically stable, due to the presence of strong intramolecular hydrogen bonding. These mesoporous hollow sphere Covalent Organic Frameworks are used for a trypsin immobilization study, which shows an uptake of 15.5 μmol g^−1 of trypsin.
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a Covalent Organic Framework cadmium sulfide hybrid as a prototype photocatalyst for visible light driven hydrogen production
Chemistry: A European Journal, 2014Co-Authors: Jayshri Thote, David Diaz Diaz, Harshitha Barike Aiyappa, Sreekumar Kurungot, Aparna Deshpande, Rahul BanerjeeAbstract:CdS nanoparticles were deposited on a highly stable, two-dimensional (2D) Covalent Organic Framework (COF) matrix and the hybrid was tested for photocatalytic hydrogen production. The efficiency of CdS-COF hybrid was investigated by varying the COF content. On the introduction of just 1 wt% of COF, a dramatic tenfold increase in the overall photocatalytic activity of the hybrid was observed. Among the various hybrids synthesized, that with 10 wt% COF, named CdS-COF (90:10), was found to exhibit a steep H2 production amounting to 3678 μmol h(-1) g(-1), which is significantly higher than that of bulk CdS particles (124 μmol h(-1) g(-1)). The presence of a π-conjugated backbone, high surface area, and occurrence of abundant 2D hetero-interface highlight the usage of COF as an effective support for stabilizing the generated photoelectrons, thereby resulting in an efficient and high photocatalytic activity.
Aurelio Mateoalonso - One of the best experts on this subject based on the ideXlab platform.
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a wavy two dimensional Covalent Organic Framework from core twisted polycyclic aromatic hydrocarbons
Journal of the American Chemical Society, 2019Co-Authors: Marta Martinezabadia, Akinori Saeki, Craig T Stoppiello, Karol Strutynski, Belen Lermaberlanga, Carlos Martigastaldo, Manuel Mellefranco, Andrei N Khlobystov, Aurelio MateoalonsoAbstract:A high degree of crystallinity is an essential aspect in two-dimensional Covalent Organic Frameworks, as many properties depend strongly on the structural arrangement of the different layers and their constituents. We introduce herein a new design strategy based on core-twisted polycyclic aromatic hydrocarbon as rigid nodes that give rise to a two-dimensional Covalent Organic Framework with a wavy honeycomb (chairlike) lattice. The concave–convex self-complementarity of the wavy two-dimensional lattice guides the stacking of Framework layers into a highly stable and ordered Covalent Organic Framework that allows a full 3D analysis by transmission electron microscopy revealing its chairlike honeycomb facets and aligned mesoporous channels. Remarkably, the waviness of the Framework does not disrupt the interlayer π–π stacking that shows charge transporting properties similar to those of planar Covalent Organic Frameworks. The implementation of core-twisted aromatics as building blocks for Covalent Organic Frameworks brings new possibilities in the design of highly ordered Organic materials.
Yaqi Cai - One of the best experts on this subject based on the ideXlab platform.
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construction of a superior visible light driven photocatalyst based on a c3n4 active centre photoelectron shift platform electron withdrawing unit triadic structure Covalent Organic Framework
Chemical Communications, 2017Co-Authors: Qinfeng Rong, Hongyun Niu, Yaqi CaiAbstract:Herein, three functional factors inducing photocatalytic ability were artfully integrated into a Covalent Organic Framework (COF), where triazine units served as photoactive centers, cyclic ketone units served as electron-withdrawing moieties, and the conjugated structure served as a photoelectron shift platform. This COF with segregated donor–acceptor alignments exhibits an excellent visible-light photocatalytic capacity for the decomposition of Organic pollutants.
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facile synthesis of magnetic Covalent Organic Framework with three dimensional bouquet like structure for enhanced extraction of Organic targets
ACS Applied Materials & Interfaces, 2017Co-Authors: Tao Zeng, Hongyun Niu, Saihua Wang, Yaqi CaiAbstract:A facile strategy for the fabrication of novel bouquet-shaped magnetic porous nanocomposite via grafting a Covalent Organic Framework (COF, TpPa-1) onto the surface-modified Fe3O4 nanoparticles (Fe3O4 NPs) was reported. The magnetic TpPa-1 (a COF synthesized from 1,3,5-triformylphloroglucinol (Tp) and p-phenylenediamine (Pa-1)) contains clusters of core–shell magnetic nanoparticles and interconnected porous TpPa-1 nanofibers. Thus, it possesses larger specific surface area, higher porosity, and supermagnetism, making it an ideal sorbent for enrichment of trace analytes. Its performance was evaluated by the magnetic solid-phase extraction (MSPE) of trace polycyclic aromatic hydrocarbons (PAHs) from environmental samples prior to high-performance liquid chromatographic analysis. The results indicated that the magnetic TpPa-1 possessed superior enrichment capacity of such Organic compounds.
Sharath Kandambeth - One of the best experts on this subject based on the ideXlab platform.
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Triazine Functionalized Porous Covalent Organic Framework for Photo-organocatalytic E–Z Isomerization of Olefins
2019Co-Authors: Mohitosh Bhadra, Sharath Kandambeth, Manoj K. Sahoo, Matthew Addicoat, Ekambaram Balaraman, Rahul BanerjeeAbstract:Visible light-mediated photocatalytic Organic transformation has drawn significant attention as an alternative process for replacing thermal reactions. Although precious metal/Organic dyes based homogeneous photocatalysts have been developed, their toxic and nonreusable nature makes them inappropriate for large-scale production. Therefore, we have synthesized a triazine and a keto functionalized nonmetal based Covalent Organic Framework (TpTt) for heterogeneous photocatalysis. As the catalyst shows significant absorption of visible light, it has been applied for the photocatalytic uphill conversion of trans-stilbene to cis-stilbene in the presence of blue light-emitting diodes with broad substrate scope via an energy transfer process
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selective molecular sieving in self standing porous Covalent Organic Framework membranes
Advanced Materials, 2017Co-Authors: Sharath Kandambeth, Bishnu P Biswal, Harshal D Chaudhari, Kanhu Charan Rout, Shebeeb H Kunjattu, Shouvik Mitra, Suvendu Karak, Anuja Das, Rabibrata Mukherjee, Ulhas K KharulAbstract:Self-standing, flexible, continuous, and crack-free Covalent-Organic-Framework membranes (COMs) are fabricated via a simple, scalable, and highly cost-effective methodology. The COMs show long-term durability, recyclability, and retain their structural integrity in water, Organic solvents, and mineral acids. COMs are successfully used in challenging separation applications and recovery of valuable active pharmaceutical ingredients from Organic solvents.
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a mechanochemically synthesized Covalent Organic Framework as a proton conducting solid electrolyte
Journal of Materials Chemistry, 2016Co-Authors: Digambar Balaji Shinde, Sharath Kandambeth, Bishnu P Biswal, Harshitha Barike Aiyappa, Mohitosh Bhadra, Pritish WadgeAbstract:Mechanochemistry has become an increasingly important synthetic tool for a waste-free environment. However, the poor quality of the so-derived materials in terms of their crystallinity and porosity has been their major drawback for any practical applications. In this report, we have for the first time successfully leveraged such characteristics to show that the mechanochemically synthesized bipyridine based Covalent Organic Framework (COF) outperforms its conventional solvothermal counterpart as an efficient solid-state electrolyte in PEM fuel cells. Marking the first such attempt in COFs, a Membrane Electrode Assembly (MEA) fabricated using the mechanochemically synthesized COF was observed to inhibit the fuel crossover and build up a stable Open Circuit Voltage (OCV = 0.93 V at 50 °C), thereby establishing itself as an effective solid electrolyte material (with a proton conductivity of 1.4 × 10−2 S cm−1), while the solvothermally synthesized COF proved ineffective under similar conditions.
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Self-templated chemically stable hollow spherical Covalent Organic Framework
Nature Communications, 2015Co-Authors: Sharath Kandambeth, V. Venkatesh, Digambar B. Shinde, Sushma Kumari, Arjun Halder, Sandeep Verma, Rahul BanerjeeAbstract:Hollow, spherical nano/microstructures are potentially useful for energy and drug delivery applications. Here, the authors show that these structures can be fabricated from Covalent Organic Frameworks, and exploit their chemical stability and mesoporous structures for enzyme encapsulation. Covalent Organic Frameworks are a family of crystalline porous materials with promising applications. Although active research on the design and synthesis of Covalent Organic Frameworks has been ongoing for almost a decade, the mechanisms of formation of Covalent Organic Frameworks crystallites remain poorly understood. Here we report the synthesis of a hollow spherical Covalent Organic Framework with mesoporous walls in a single-step template-free method. A detailed time-dependent study of hollow sphere formation reveals that an inside-out Ostwald ripening process is responsible for the hollow sphere formation. The synthesized Covalent Organic Framework hollow spheres are highly porous (surface area ∼1,500 m^2g^−1), crystalline and chemically stable, due to the presence of strong intramolecular hydrogen bonding. These mesoporous hollow sphere Covalent Organic Frameworks are used for a trypsin immobilization study, which shows an uptake of 15.5 μmol g^−1 of trypsin.
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multifunctional and robust Covalent Organic Framework nanoparticle hybrids
Journal of Materials Chemistry, 2014Co-Authors: Pradip Pachfule, Sharath Kandambeth, David Diaz Diaz, Manas K Panda, S M Shivaprasad, Rahul BanerjeeAbstract:Highly dispersed Pd(0) nanoparticles were successfully immobilized into a stable, crystalline and porous Covalent Organic Framework (COF), TpPa-1, by a solution infiltration method using NABH4 as a reducing agent. High resolution and dark field TEM images confirmed the uniform loading of the Pd(0) nanoparticles into the TpPa-1 matrix without aggregation. This hybrid material exhibited excellent catalytic activity towards the Cu free Sonogashira, Heck and sequential one pot Heck–Sonogashira cross-coupling reactions under basic conditions, and with superior performance compared to commercially available Pd supported on activated charcoal (i.e., 1, 5 and 10 wt%). Additionally, the precursor Pd(II)-doped COF also displayed competitive catalytic activity for the intramolecular oxidative biaryl synthesis under acidic conditions. Both catalysts were found to be highly stable under the reaction conditions showing negligible metal leaching, non-sintering behavior, and good recyclability. To the best of our knowledge, the Organic support used in this work, TpPa-1, constitutes the first COF matrix that can hold both Pd(0) nanoparticles and Pd(II) complex without aggregation for catalytic purposes under both highly acidic and basic conditions.
Xiaoming Liu - One of the best experts on this subject based on the ideXlab platform.
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a robust and luminescent Covalent Organic Framework as a highly sensitive and selective sensor for the detection of cu 2 ions
Chemical Communications, 2016Co-Authors: Yuwei Zhang, Hong Xia, Xiaoming LiuAbstract:A hydrogen bond assisted azine-linked Covalent Organic Framework, COF-JLU3, was synthesized under solvothermal conditions. Combining excellent crystallinity, porosity, stability and luminescence, it can be the first COF as a fluorescent sensor for toxic metal ions, exhibiting high sensitivity and selectivity to Cu(2+).
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a robust and luminescent Covalent Organic Framework as a highly sensitive and selective sensor for the detection of cu2 ions
Chemical Communications, 2016Co-Authors: Zhongping Li, Hong Xia, Yuwei Zhang, Ying Mu, Xiaoming LiuAbstract:A hydrogen bond assisted azine-linked Covalent Organic Framework, COF-JLU3, was synthesized under solvothermal conditions. Combining excellent crystallinity, porosity, stability and luminescence, it can be the first COF as a fluorescent sensor for toxic metal ions, exhibiting high sensitivity and selectivity to Cu2+.
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an azine linked Covalent Organic Framework synthesis characterization and efficient gas storage
Chemistry: A European Journal, 2015Co-Authors: Yongfeng Zhi, Xiao Feng, Xuesong Ding, Yongcun Zou, Xiaoming LiuAbstract:A azine-linked Covalent Organic Framework, COF-JLU2, was designed and synthesized by condensation of hydrazine hydrate and 1,3,5-triformylphloroglucinol under solvothermal conditions for the first time. The new Covalent Organic Framework material combines permanent micropores, high crystallinity, good thermal and chemical stability, and abundant heteroatom activated sites in the skeleton. COF-JLU2 possesses a moderate BET surface area of over 410 m(2) g(-1) with a pore volume of 0.56 cm(3) g(-1) . Specifically, COF-JLU2 displays remarkable carbon dioxide uptake (up to 217 mg g(-1) ) and methane uptake (38 mg g(-1) ) at 273 K and 1 bar, as well as high CO2 /N2 (77) selectivity. Furthermore, we further highlight that it exhibits a higher hydrogen storage capacity (16 mg g(-1) ) than those of reported COFs at 77 K and 1 bar.
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a 2d azine linked Covalent Organic Framework for gas storage applications
Chemical Communications, 2014Co-Authors: Xiao Feng, Yongcun Zou, Yuwei Zhang, Hong Xia, Xiaoming LiuAbstract:A new azine-linked Covalent Organic Framework, ACOF-1, was synthesized by condensation of hydrazine hydrate and 1,3,5-triformylbenzene under solvothermal conditions. ACOF-1 has a high surface area and a small pore size, and it can store up to 177 mg g(-1) of CO2, 9.9 mg g(-1) of H2, and 11.5 mg g(-1) of CH4, at 273 K and 1 bar, with high selectivity towards CO2 over N2 and CH4.
