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290 results on '"Mondal, John"'

1. Metalated Porous-Organic-Polymer Renders Mustard-Gas Simulant Harmless: Core Planarity Matters

Author

Paul, Ratul, Sarkar, Chitra, Jain, Manjari, Xu, Shaojun, Borah, Kashmiri, Dao, Duy Quang, Pao, Chih-Wen, Bhattacharya, Saswata, and Mondal, John

Subjects
Condensed Matter - Materials Science
Abstract

The presence of open active metal sites in Metal-Organic Frameworks (MOFs) exhibit higher catalytic activity. However, rational accomplishment of MOFs in heterogeneous catalysis is limited due to coordination bonds. Recently balanced characteristic feature with combination of both the covalent bonds (structural stability) and open metal sites (single site catalysis) introduced an entirely organic alternative architecture named as Metalated Porous-Organic-Polymers (M-POPs). In this contribution, we demonstrate successful construction of two Fe-POPs (Fe-Tt-POP & Fe-Rb-POP) by ternary copolymerization approach for catalytic oxidative decontamination of different sulfur-based mustard gas simulants. Fe-Tt-POP exhibited superior catalytic performance for oxidation of the thioanisole (TA) studied in terms of conversion (99% after 13 h) in comparison with Fe-Rb-POP (43% after 13h). The remarkable difference in the mechanistic pathways towards catalytic performance for oxidation of TA was investigated by in situ operando Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS) analysis, complemented by Density Functional Theory (DFT) computational study., Comment: 9 pages excluding SI, 49 pages in total

Published
2022

9. Tweaking Photo CO2 Reduction by Altering Lewis Acidic Sites in Metalated‐Porous Organic Polymer for Adjustable H2/CO Ratio in Syngas Production.

Author

Paul, Ratul, Das, Risov, Das, Nitumani, Chakraborty, Subhajit, Pao, Chih‐Wen, Thang Trinh, Quang, Kalhara Gunasooriya, G. T. Kasun, Mondal, John, and Peter, Sebastian C.

Subjects
POROUS polymers, STRUCTURE-activity relationships, ELECTRON density, PHOTOREDUCTION, SYNTHESIS gas, LEWIS acids, POLYMERS
Abstract

Herein, we have specifically designed two metalated porous organic polymers (Zn‐POP and Co‐POP) for syngas (CO+H2) production from gaseous CO2. The variable H2/CO ratio of syngas with the highest efficiency was produced in water medium (without an organic hole scavenger and photosensitizer) by utilizing the basic principle of Lewis acid/base chemistry. Also, we observed the formation of entirely different major products during photocatalytic CO2 reduction and water splitting with the help of the two catalysts, where CO (145.65 μmol g−1 h−1) and H2 (434.7 μmol g−1 h−1) production were preferentially obtained over Co‐POP & Zn‐POP, respectively. The higher electron density/better Lewis basic nature of Co‐POP was investigated further using XPS, XANES, and NH3‐TPD studies, which considerably improve CO2 activation capacity. Moreover, the structure–activity relationship was confirmed via in situ DRIFTS and DFT studies, which demonstrated the formation of COOH* intermediate along with the thermodynamic feasibility of CO2 reduction over Co‐POP while water splitting occurred preferentially over Zn‐POP. [ABSTRACT FROM AUTHOR]

Published
2023
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11. Experimental Validation and Computational Predictions Join Forces to Map Catalytic C–H Activation in Ferrocene Metalated Porous Organic Polymers

Author

Boro, Bishal, primary, Paul, Ratul, additional, Tan, Hui Ling, additional, Trinh, Quang Thang, additional, Rabeah, Jabor, additional, Chang, Chia-Che, additional, Pao, Chih-Wen, additional, Liu, Wen, additional, Nguyen, Nam-Trung, additional, Mai, Binh Khanh, additional, and Mondal, John, additional

Published
2023
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16. Discrete Cu-Metalloporous Polycarbazole as a Nanoelectromediator for Effective Electrocarboxylation of Benzyl Bromide with CO2.

Author

Boro, Bishal, Kalita, Priyanka, Vijayaprabhakaran, Aathilingam, Dao, Duy Quang, Nandy, Subhajit, Chae, Keun Hwa, Nailwal, Yogendra, Kathiresan, Murugavel, and Mondal, John

Abstract

The electrochemical fixation of carbon dioxide (CO2) into organic halides is one of the most prominent strategies for mitigating atmospheric CO2 emission, along with the difficulties associated with the toxic and carcinogenic halogenated compounds. Cu-based nanomaterials have been explored for numerous applications in nanotechnology, including electrocatalysis, organic catalytic transformations, and photocatalysis. In this work, we have designed and developed a Cu-embedded carbazole-derived porous organic polymer (Cu@Cz-POP) nanohybrid by utilizing the Friedel–Crafts alkylation approach and employing 1,4-dimethoxybenzene as the cross-linking agent comprising unique characteristic features of the extended π-conjugated system along with an active metal center with tunable electrochemical properties. The Brunauer–Emmett–Teller surface area of the conjugated Cz-POP is found to be 1060 m2 g–1. The X-ray photoelectron spectroscopy (XPS) study demonstrates the formation of CuO nanoparticles in the polymeric framework. X-ray absorption fine structure analysis (EXAFS) also reveals the existence of CuO with a smaller fraction of Cu in the polymeric framework, which is corroborated with the XPS analysis. The Cu@Cz-POP nanohybrid is fabricated by drop-casting over a Ni foam, showing promising electrocatalytic activity toward electrocarboxylation of benzyl bromide in 0.1 M TBA·BF4/CH3CN with saturated CO2 medium with a current density of 120 mA cm–2 delivering 65% yield of phenylacetic acid (PAA) as the primary product along with traces of benzyl 2-phenylacetate (BPA) and 1,2-diphenylethane (DPE), and the turnover frequency is found to be 8.556 × 10–7 s–1. Density functional theory calculations demonstrate that CuO is adsorbed more favorably at the N1 nitrogen atom of Cz-POP. An electron transfer from the N1 atom and the aromatic rings of Cz-POP to the CuO center is observed and confirmed by the overlap of alpha orbitals. [ABSTRACT FROM AUTHOR]

Published
2023
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27. Tuning of Microenvironment in Covalent Organic Framework via Fluorination Strategy promotes Selective CO2 Capture.

Author

Das, Nitumani, Paul, Ratul, Chatterjee, Rupak, Shinde, Digambar Balaji, Lai, Zhiping, Bhaumik, Asim, and Mondal, John

Subjects
FLUORINATION, ADSORPTION capacity, SURFACE area, CARBON dioxide
Abstract

Herein, we have designed and synthesized two heteroatom (N, O) rich covalent organic frameworks (COF), PD‐COF and TF‐COF, respectively, to demonstrate their relative effect on CO2 adsorption capacity and also CO2/N2 selectivity. Compared to the non‐fluorinated PD‐COF (BET surface area 805 m2 g−1, total pore volume 0.3647 ccg−1), a decrease in BET surface area and also pore volume have been observed for fluorinated TF‐COF due to the incorporation of fluorine to the porous framework (BET surface area 451 m2 g−1, total pore volume 0.2978 ccg−1). This fact leads to an enormous decrease in the CO2 adsorption capacity and CO2/N2 selectivity of TF‐COF, though it shows stronger affinity towards CO2 with a Qst of 37.76 KJ/mol. The more CO2 adsorption capacity by PD‐COF can be attributed to the large specific surface area with considerable amount of micropore volume compared to the TF‐COF. Further, PD‐COF exhibited CO2/N2 selectivity of 16.8, higher than that of TF‐COF (CO2/N2 selectivity 13.4). [ABSTRACT FROM AUTHOR]

Published
2023
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28. Selective photocatalytic CO2 reduction to CH4 over metal-free porous polyimide in the solid–gas mode.

Author

Shit, Subhash Chandra, Powar, Niket S., Kalita, Priyanka, Paul, Ratul, Xu, Shaojun, Jung, Jin-Woo, Cho, Chang-Hee, In, Su-Il, and Mondal, John

Subjects
PHOTOREDUCTION, VISIBLE spectra, POLYIMIDES, POLYCONDENSATION, IRRADIATION
Abstract

Using a catalyst-free one-pot polycondensation approach, a new donor–acceptor (D–A) based porous polyimide (PeTt–POP) photocatalyst was developed. PeTt–POP produced CH4 (125.63 ppm g−1 in 6 h) from CO2 under visible light irradiation in the gas–solid mode without the use of co-catalysts or sacrificial agents. The progress of the reaction and the corresponding intermediate species involved in the CO2 reduction were identified by operando DRIFTS experiments, from which a plausible reaction mechanism was proposed. [ABSTRACT FROM AUTHOR]

Published
2022
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39. Engineering the Charge Density on an In2.77S4/Porous Organic Polymer Hybrid Photocatalyst for CO2-to-Ethylene Conversion Reaction

Author

Das, Risov, Paul, Ratul, Parui, Arko, Shrotri, Abhijit, Atzori, Cesare, Lomachenko, Kirill A., Singh, Abhishek Kumar, Mondal, John, and Peter, Sebastian C.

Abstract

The development of an efficient photocatalyst for C2 product formation from CO2is of urgent importance toward the deployment of solar-fuel production. Here, we report a template-free, cost-effective synthetic strategy to develop a carbazole-derived porous organic polymer (POP)-based composite catalyst. The composite catalyst is comprised of In2.77S4and porous organic polymer (POP) and is held together by induced-polarity-driven electrostatic interaction. Utilizing the synergy of the catalytically active In centers and light-harvesting POPs, the catalyst showed 98.9% selectivity toward the generation of C2H4, with a formation rate of 67.65 μmol g–1h–1. Two different oxidation states of the In2.77S4spinel were exploited for the C–C coupling process, and this was investigated by X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (XAS), and density functional theory (DFT) calculations. The role of POP was elucidated viaseveral photophysical and photoelectrochemical studies. The electron transfer was mapped by several correlated approaches, which assisted in establishing the Z-scheme mechanism. Furthermore, the mechanism of C2H4formation was extensively investigated using density functional theory (DFT) calculations from multiple possible pathways.

Published
2023
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43. Nanospace Engineering of Triazine−Thiophene-Intertwined Porous-Organic-Polymers via Molecular Expansion in Tweaking CO2 Capture.

Author

Das, Nitumani, Paul, Ratul, Dao, Duy Quang, Chatterjee, Rupak, Borah, Kashmiri, Chandra Shit, Subhash, Bhaumik, Asim, and Mondal, John

Abstract

Post-combustion CO2 capture, storage, and separation have garnered colossal research interest in the energy industry, although realistic implementation of the available porous adsorbents is restricted owing to their cost competitiveness, stability, and scalability issues. The integration of heteroatom functionalities (N, O, or S) at the molecular level into the organic skeleton of porous framework materials endowed them with superior CO2 adsorbents to mitigate greenhouse gases. In this work, we have successfully introduced triazine–thiophene (Tt) groups to the nanoporous organic polymer (POP) skeleton by Friedel–Craft alkylation of Tt (as a monomer) with a series of cross-linking agents including formaldehyde dimethyl acetal, 1,4-bis-(bromomethyl)-benzene (BMB), and 4,4′-bis-(bromomethyl)-biphenyl, which contained methylene, bis-methylene benzene, and bis-methylene biphenyl moieties in each linker unit, respectively. The precise skeleton engineering with the variation of organic cross-linking agents at the molecular level leads to the development of Tt-POP-1, Tt-POP-2, and Tt-POP-3, having nanorod-, nanocoral-, and nanocloud-like morphologies, respectively. In particular, at 273 K, Tt-POP- 1, Tt-POP- 2, and Tt-POP-3 exhibited CO2 uptake capacities of about 33.04, 40.06, and 34.12 cm3/g, respectively, up to 1 bar pressure. Interestingly, Tt-POP-2 bearing a BMB linker exhibited enhanced CO2 uptake capacity both at 298 and 273 K in comparison with the other Tt-POP-1 and Tt-POP-3, respectively. An in-depth study of the CO2 adsorption mechanism by density functional theory calculations showed that the benzyl rings of linker units in Tt-POP-2 and Tt-POP-3 play a pivotal role in CO2 uptake. The more polarized interaction of CO2 with the thiophenyl and benzyl rings compared to the N and S atoms in Tt-POP-2 results in enhanced CO2 uptake capacity with respect to the others. [ABSTRACT FROM AUTHOR]

Published
2022
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44. Navigating Copper-Atom-Pair Structural Effect inside a Porous Organic Polymer Cavity for Selective Hydrogenation of Biomass-Derived 5-Hydroxymethylfurfural

Author

Sarkar, Chitra, primary, Paul, Ratul, additional, Chandra Shit, Subhash, additional, Trinh, Quang Thang, additional, Koley, Paramita, additional, Rao, Bolla Srinivasa, additional, Beale, Andrew M., additional, Pao, Chih-Wen, additional, Banerjee, Arghya, additional, and Mondal, John, additional

Published
2021
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47. Realizing Catalytic Acetophenone Hydrodeoxygenation with Palladium-Equipped Porous Organic Polymers

Author

Paul, Ratul, primary, Shit, Subhash Chandra, additional, Fovanna, Thibault, additional, Ferri, Davide, additional, Srinivasa Rao, Bolla, additional, Gunasooriya, G. T. Kasun Kalhara, additional, Dao, Duy Quang, additional, Le, Quyet Van, additional, Shown, Indrajit, additional, Sherburne, Matthew P., additional, Trinh, Quang Thang, additional, and Mondal, John, additional

Published
2020
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