Faculty Publications
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Item Photo- and Electrocatalytic Reduction of CO2 over Metal-Organic Frameworks and Their Derived Oxides: A Correlation of the Reaction Mechanism with the Electronic Structure(American Chemical Society, 2022) Payra, S.; Ray, S.; Sharma, R.; Tarafder, K.; Mohanty, P.; Roy, S.A Ce/Ti-based bimetallic 2-aminoterephthalate metal-organic framework (MOF) was synthesized and evaluated for photocatalytic reduction of CO2 in comparison with an isoreticular pristine monometallic Ce-terephthalate MOF. Owing to highly selective CO2 adsorption capability, optimized band gaps, higher flux of photogenerated electron-hole pairs, and a lower rate of recombination, this material exhibited better photocatalytic reduction of CO2 and lower hydrogen evolution compared to Ce-terephthalate. Thorough probing of the surface and electronic structure inferred that the reducibility of Ce4+ to Ce3+ was due to the introduction of an amine functional group into the linker, and low-lying Ti(3d) orbitals in Ce/Ti-2-aminoterephthalate facilitated the photoreduction reaction. Both the MOFs were calcined to their respective oxides of Ce1-xTixO2 and CeO2, and the electrocatalytic reduction of CO2 was performed over the oxidic materials. In contrast to the photocatalytic reaction mechanism, the lattice substitution of Ti in the CeO2 fluorite cubic structure showed a better hydrogen evolution reaction and consequently, poorer electroreduction of CO2 compared to pristine CeO2. Density functional theory calculations of the competitive hydrogen evolution reaction on the MOF and the oxide surfaces corroborated the experimental findings. © 2022 American Chemical Society.Item Unprecedented Electroreduction of CO2over Metal Organic Framework-Derived Intermetallic Nano-Alloy Cu0.85Ni0.15/C(American Chemical Society, 2022) Payra, S.; Devaraj, N.; Tarafder, K.; Roy, S.Designing suitable catalysts for efficient and selective electrocatalytic reduction of CO2 is a need of the hour, and in this regard, the well-defined, highly dispersed active metal centers can be a trendsetting research endeavor toward CO2 electroreduction due to the maximum atom utilization and unique electronic structure. This study describes the synthesis and electrocatalytic CO2 reduction activity of atomistically dispersed Cu/C and Ni/C and the intermetallic nano-alloy Cu0.85 Ni0.15 /C. The catalysts were synthesized from the corresponding MOF precursors. The successful synthesis of the monometallic and intermetallic nano-alloys was established from structural, surface morphological, and electronic properties. Cu0.85 Ni0.15 /C exhibited an unprecedented electrocatalytic reduction of CO2 with a high selectivity and high faradaic efficiency toward CH3 OH. The kinetic studies and the first-principles calculations elucidated the intricate mechanism and the superior activity of electrocatalytic reduction of CO2 over the intermetallic Cu0.85 Ni0.15 /C catalyst. © 2022 American Chemical Society. All rights reserved.Item Distal Synergistic Effect in Bimetal-Organic Framework for Superior Catalytic Water Oxidation(American Chemical Society, 2023) Bhoi, U.; Ray, S.; Bhand, S.; Ninawe, P.; Roy, D.; Rana, S.; Tarafder, K.; Ballav, N.Metal-organic frameworks (MOFs) are emerging as promising electro-catalysts for the oxygen evolution reaction (OER). The bimetallic design strategy was further adopted in MOFs to elevate the OER performance by a synergistic effect. The proximal metal-oxygen-metal bonding configuration with typical 3dπ-2pπ-3dπ interaction was apparently essential for an effective electronic coupling between the metal centers. Here, we report an example of distal synergy in a bimetal-organic framework exhibiting a better OER activity than the monometallic counterparts, as well as the conventional proximal synergy. To achieve a current density of 10 mA·cm-2, our electrodeposited bimetallic MOF, Co-Ni(TCNQ)2(H2O)2 (TCNQ = 7,7,8,8-tetracyanoquinodimethane), on a glassy-carbon electrode required an overpotential value of 220 mV. X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) calculations revealed distinctive electronic coupling between the Co(II)-3d7 and Ni(II)-3d8 centers, despite being 9 Å apart, leading to an overall charge delocalization in the structure via TCNQ. © 2023 American Chemical Society.Item Ag Nanoparticles-Induced Metallic Conductivity in Thin Films of 2D Metal-Organic Framework Cu3(HHTP)2(American Chemical Society, 2023) Saha, S.; Ananthram, K.S.; Hassan, N.; Ugale, A.; Tarafder, K.; Ballav, N.Two-dimensional (2D) metal-organic frameworks (MOFs) are usually associated with higher electrical conductivity and charge carrier mobility when compared with 3D MOFs. However, attaining metallic conduction in such systems through synthetic or postsynthetic modifications is extremely challenging. Herein, we present the fabrication of thin films of a 2D MOF, Cu3(HHTP)2 (HHTP = 2,3,6,7,10,11-hexahydroxytriphenylene), decorated with silver nanoparticles (AgNPs) exhibiting significant conductivity enhancement at room temperature. Variable-temperature electrical transport measurements across the low-temperature (200 K) to high-temperature (373 K) regime evidenced metallic conduction. Interestingly, thin films of a 3D MOF, CuTCNQ (TCNQ = 7,7,8,8-tetracyanoquinodimethane), upon decoration with AgNPs, disclosed a converse trend. The origin of such distinctive observations on AgNPs@Cu3(HHTP)2 and AgNPs@CuTCNQ systems was comprehended by using first-principles density functional theory (DFT) calculations and attributed to an interfacial electronic effect. Our work sheds new light on rationally designing synthetic modifications in thin films of MOFs to tune the electrical transport property. © 2023 American Chemical Society.Item Synthesis and application of Zr-metal–organic framework for simultaneous detection and rapid adsorption of p-nitrophenol from water(Institute for Ionics, 2023) Nimbalkar, M.N.; Badekai Ramachandra, B.R.The p-nitrophenol is a prime raw material in the manufacturing of pharmaceutical drugs, fungicides and insecticides. The effluents from these industries contain p-nitrophenol and are harmful to human and aquatic life. Hence, development of fast detection and efficient disposal process of p-nitrophenol in wastewater is a major concern. In this study, fluorescent active smart metal–organic framework (MOF) was employed for the simultaneous detection and adsorptive removal of p-nitrophenol from water. Photoluminescence active zirconium-based metal–organic framework having isostructural with UiO-66 framework was synthesized by using mixed ligand strategy with the replacement of BDC (1,4-Benzenedicarboxylic acid) ligand from 10 to 30 mol% with H3ntb ligand (4,4ʼ,4ʼʼ-Nitrilotrisbenzoic acid, in house synthesised fluorescence active trifunctional ligand). The powder X-ray diffraction (PXRD), analysis of the synthesised MOF confirms face centred cubic (FCC) crystal structure similar to pristine UiO-66. From Fourier transform infrared spectroscopy (FTIR), the peak at 1251 cm−1 for the tertiary amine group validated the presence of H3ntb ligand. The obtained MOFs have the surface area from 1039 m2g−1 to 949.1 m2g−1 and pore volume ranging from 0.04973 cm3g−1 to 0.05160 cm3g−1. Experimental results indicated that MOF was able to detect p-nitrophenol at low concentration (≈35 μM) and to remove rapidly (< 10 min) it from the aqueous solution. The adsorption process obeys Langmuir isotherm (monolayer adsorption capacity is 62 mgg−1) and kinetics by Elovich model indicating adsorption nature as chemisorption on a heterogeneous surface. Graphical abstract: [Figure not available: see fulltext.] © 2022, The Author(s) under exclusive licence to Iranian Society of Environmentalists (IRSEN) and Science and Research Branch, Islamic Azad University.Item Formulation and optimization of Ni-MOF/CuSe nanocomposite ink for high-performance flexible microsupercapacitor(Elsevier Ltd, 2024) Saquib, M.; Muthu, M.; Nayak, R.; Prakash, A.; Sudhakar, Y.N.; SenthilKumar, S.; Bhat, D.K.The growth of flexible and wearable electronics drives progress in printed, flexible micro-supercapacitors for energy storage. This study fabricates flexible and foldable micro-supercapacitors using a nanocomposite of Ni-based Metal-Organic Framework (Ni-MOF) and copper selenide (CuSe). The conductive ink, blending Ni-MOF and CuSe, ensures thorough mixing for screen-printing. The resulting devices exhibit impressive electrochemical performance, with the NC-5 FAS device showing high areal capacitance, promising energy density and (3.65 mWhcm?2 and power density (73.8 mWcm?2). Integration into a 3D enclosure configuration enhances performance, with improved capacitance, energy density (47.08 mWhcm?2) and power density and outstanding power density (985.8 mWcm?2), maintaining capacitance retention of the 93.9 % and with highly robust mechanical durability during flexibility tests. This study highlights tailored nanocomposite's potential to revolutionize flexible and foldable energy storage, advancing high-performance, portable electronics. © 2024Item Efficient removal of hazardous dyes/heavy-metal ions by in-house fabricated poly (vinylidene fluoride) thin-film nanocomposite membranes with functionalized Zr-based metal-organic framework(Elsevier Ltd, 2025) Prabhakar, N.; Isloor, A.M.; Farnood, R.; A.F., A.F.The need for effective solutions to address removal of dyes and heavy metal ions from water has driven significant interest in membrane science and separation technology. This work explores the potential of EDTA-modified MOF-808 as a novel additive to enhance the performance of PVDF supported TFC membranes. The innovation lies in aiming the unique properties of MOF and the chelating properties of EDTA in rejecting the target pollutants. The thin film nanocomposite membranes fabricated in this study with optimized MOF-EDTA loading demonstrated remarkable improvement in hydrophilicity, surface smoothness, porosity, and morphology as confirmed by water contact angle, atomic force microcopy, water uptake, and scanning electron microscopy. The optimized membrane with 0.1wt% MOF-808-EDTA exhibited a water flux of 37.36 Lm-2h-1, a 2.7-fold increment compared to the unmodified one. This was complemented by 98.6%, 91.48%, 88.7%, and 88.96% rejections in hazardous heavy metal ions namely lead, arsenite, cadmium and mercury respectively along with more than 95% rejections for 50ppm of sunset yellow and reactive black 5 dyes. The study also highlights the significant enhancement in antifouling properties with a reduction in irreversible fouling from 41.5% to 5.68% along with a flux rejection ratio of 94.3%. These findings underscore the potential of EDTA-modified MOF as an additive in enhancing the performance and durability of TFC membranes paving the way for efficient and sustainable water treatment. The current study explores an innovative approach for mitigating heavy metal ion and dye pollution in water via fabrication of. © 2025 Published by Elsevier Ltd.Item A polysulfone/MIL-125(Ti) mixed matrix membrane for removing toxic dyes and heavy metals from water(Springer Science and Business Media Deutschland GmbH, 2025) Shivarama, B.; Isloor, A.M.; Murthy, C.S.; Prabhu, B.; Abdul Rashid, S.A.In this work, a titanium-incorporated metal–organic framework nanoadditive was used to study its efficiency in removing heavy metals and dyes from contaminated water. The use of MIL-125 (Ti) nanoadditive-incorporated polysulfone membranes has been tested for the elimination of heavy metals such as cadmium and lead as well as synthetic dyes, such as reactive black-5 (RB-5) and reactive orange -16 (RO-16). The incorporation of metal–organic frameworks (MOFs) into polysulfone matrices can increase the performance of the membrane for specific applications, such as dye removal and heavy metal rejection. The MIL-125 (Ti) is a well-known MOF with excellent chemical stability, large surface area, and adjustable pore size, making it suitable for membrane fabrication. This study fabricated membranes composed of MIL-125(Ti) and polysulfone (PSF) with MOF doses ranging from 0.5 to 3 wt %. Compared with the pristine PSF membrane, the pore-forming agent PVP was used at a 12% concentration, increasing the pore size and porosity. The hydrophilicity, water flux, and antifouling nature of the fabricated membrane were studied. The dye removal and heavy metal rejection experiments were carried out, and a dye removal efficiency of 90% for RB-5 and 47% for RO-16 was exhibited by the M-1 membrane. Furthermore, the M-2 membrane resulted in heavy metal rejection of 89.33% for Cd2+, and M-3 resulted in 68.81% for Pb2+ at a feed concentration of 500 ppm. Hence, the membranes showed good stability and efficiency with a high feed concentration of heavy metals. In the present study, metal ion rejection was studied without the use of any complexing agents. © King Abdulaziz City for Science and Technology 2025.Item Fabrication and incorporation of MIL-53(Fe)-zwitterionic brushes into PVDF thin film composite membranes for enhancing heavy metal/dye rejection from aqueous body(Elsevier B.V., 2025) Prabhakar, N.; Isloor, A.M.; Farnood, R.; Fauzi Ismail, A.The bioaccumulation of heavy metal ions is a serious concern for researchers. The dyes and heavy metal ions also aquatic life impacting the biodiversity adversely. Synthesis of novel MIL-53(Fe)-PSBMA particles, and its incorporation into PVDF-based thin-film composite membranes is the crux of this work. Firstly, H2N-MIL-53(Fe) was synthesized by metal displacement reaction which was then modified into MIL-53(Fe)-PSBMA brushes. The brushes were synthesized by atom transfer radical polymerization method. The amine groups of the NH2-MIL-53(Fe) help connecting the MOF to the polymeric moiety. The as-synthesized material and the fabricated TFCs were characterized by BET, FTIR, XRD, XPS, TGA, AFM, FE-SEM, zeta potential, and DLS particle sizer. The presence of sulphur groups on the XPS spectrum of modified MOF ensured the successful polymer grafting on it. Zwitterionic moieties have both positive and negative charges within a single molecule which gave a resultant zeta potential of ?13.1 mV for the brushes. A pure water flux of 26.32 Lm?2 h?1 and 97.33 %, 95.19 %, 82.06 %, and 78.47 % rejections for Pb2+, Hg2+, As3+, Cd2+ ions and 96.23 % and 94.04 % rejection for 100 ppm reactive black-5 and sunset yellow dyes respectively were obtained for the optimized membrane having 0.035 wt% loading of zwitterionic MOF. This result was attributed to the enhanced membrane hydrophilicity which was also correlated with contact angle and water uptake studies. © 2024 Elsevier B.V.Item Sustainable waste water purification via integration of novel COF@UiO-66 dual-layer PVDF/PEI hollow fiber membranes(Elsevier B.V., 2025) Prabhakar, N.; Isloor, A.M.; Othman, M.H.D.; A.F., A.F.In the present study, dual-layer (polyvinylidene fluoride (PVDF)/ polyether imide (PEI) blend membranes were fabricated by coextrusion technique, with varying loadings (0–1.5 wt%) of covalent organic framework (COF) grafted UiO-66, for dye and heavy metal ion removal. UiO-66-NH2 was chosen for its excellent surface area and water stability, which can enhance the water permeability through the membrane without getting degraded over a period of time. The structures of the synthesized UiO-66-NH2 and COF@UiO-66 were confirmed by characterizations like scanning electron microscopy (SEM), FTIR (Fourier Transform Infrared Spectroscopy), and XRD (X-ray Diffraction). The membrane fabricated with the synthesized additive in the outer layer, was characterized by atomic force microscopy (AFM) and scanning electron microscopy (SEM) for the surface topography and morphology. The incorporation of the additive significantly affected the hydrophilicity, porosity, and surface area of the membrane, resulting in improved permeability and rejection, along with imparting relatively good antifouling nature to the membrane. Membrane with outer dope flow rate of 2 mL/min and an optimized loading of the additive (1.0 wt.%) displayed a water permeability of 117.5 Lm?2 h?1 bar?1, whereas the neat membrane showed only 60 Lm?2 h?1 bar?1. The dyes, Congo red and reactive black-5, showed rejections of 99.1 %, and 97.96 % respectively. Whereas, the heavy metal ions mercury and lead showed 69.58 %, and > 99.9 % in the complexed state with humic acid for the optimized membrane, along with a bovine serum albumin (BSA) fouling rejection ratio of 74.22 %. Whereas the neat membrane without the MOF additive showed 89 %, 79 %, 75 %, and 43 % rejections for reactive black 5, congo red, lead, and mercury ions, respectively, with an FRR of only 57 %. © 2025 Elsevier B.V.