IR@CGCRI - Central Glass and Ceramic Research Institute (CSIR)
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Accelerating full-thickness skin wound healing using Zinc and Cobalt doped-bioactive glass-coated eggshell membrane
No full textThe quest to develop advanced wound dressing with excellent healing properties is an unending clinical chal-lenge. Several biological molecules have shown promising results in this regard. We utilized eggshell membrane, a waste product generated from egg processing industries, and coated it with bioactive glass/ion-doped (Zn, Co) bioactive glass in the nanoscale range to develop four different types of wound dressing mats (ESM/BAG, ESM/ ZnBAG, ESM/CoBAG, ESM/ZnCoBAG). All the mats were cytocompatible with human dermal fibroblasts and maintained cytoskeletal and nuclear morphology up to day 14 of culture. On application of these mats over the full-thickness skin wounds in the rabbit model, enhanced wound closure was observed especially with the eggshell membrane/ion-doped bioactive glass mats. These mats also demonstrated orderly and timely deposition of ECM components i.e., collagen, elastin, and reticulin. These wound remodeling and early healing features could be attributed to the bioactive properties of eggshell membranes along with the Zinc and Cobalt doped bioactive glass. These mats thus hold enormous potential as an economic wound dressing and also in biomedical applications
In situ processing of Fe-based bulk metallic glass nanocomposites in supercooled liquid region by spark plasma sintering
No full textCurrent study reports fabrication of in-situ Fe-based bulk metallic glass (BMG) nanocomposites by carrying out spark plasma sintering of Fe57Cr9Mo5B16P7C6 amorphous alloy powder. In situ BMG composites were synthesized with varying amount of crystalline phases by controlled partial devitrification in supercooled liquid region. Application of high consolidation pressure (400 MPa) during sintering contributed to enhanced viscous flow in the amorphous powder resulted in high densification (> 97 %) in the sintered compacts. Microstructural and phase evolution in the consolidated BMGs and BMG nanocomposites were systematically investigated with respect to sintering conditions. Microscale heterogeneity with respect to phase evolution in the sintered samples was evaluated by nanoindentation studies. Hardness of the sintered BMG nanocomposites was found to be significantly higher than the sintered BMGs ascribed to the evolution of hard intermetallic phases during devitrification
Comparative Studies of Co/SBA-15 Catalysts Synthesized with Different Silica Sources Including Coal Fly Ash for Fischer-Tropsch Synthesis
No full textSBA-15 is synthesized using triblock copolymer Pluronic P123 as the structure directing agent and different silica sources such as tetraethyl orthosilicate (TEOS), sodium metasilicate, coal fly ash (CFA) derived supernatant and a mix of sodium metasilicate, CFA-derived supernatant for comparative study towards Fischer-Tropsch synthesis (FTS). The active metal cobalt (15 wt. %) has been impregnated in each support via the wet impregnation technique. The catalysts and supports are characterized by N-2 adsorption-desorption, Field Emission Scanning Electron Microscopy (FESEM), High-Resolution Transmission Electron Microscopy (HRTEM), X-ray Diffraction (XRD), X-ray Energy Dispersion Spectrophotometer (EDX), Fourier Transform Infrared (FTIR), and Temperature Programmed Reduction (TPR). The catalytic performance of synthesized catalysts for the FTS has been investigated in a fixed bed tubular reactor at T=220 degrees C, P=30 bar, and GHSV=500 h(-1) using simulated syngas composition equivalent to coal-derived syngas using air blown fixed bed gasifier having H-2/CO molar ratio of 2 : 1. The maximum CO conversion and middle distillate (C-6-C-20) selectivity is observed as 59.2 % and 84.6 % respectively for the catalyst support synthesized from mix of sodium metasilicate and CFA-derived supernatant
Engineered Li7La3Zr2O12 (LLZO) for Pseudo-Solid-State Lithium Metal Batteries (SSLMBs): Tailor-Made Synthesis, Evolution of the Microstructure, Suppression of Dendritic Growth, and Enhanced Electrochemical Performance
No full textMorphologically engineered Li7La3Zr2O12 (LLZO) impregnated with a common solvated ionic liquid (SIL) can greatly influence the cycling performance (360 cycles), coulombic efficiency (>99%), and high rate capability (0.05-1.2 mA center dot cm-2) of pseudo-solid-state lithium metal batteries (SSLMBs). In this report, to obtain a unique microstructure of cubic-LLZO, a fine-tuned combustion synthesis process was first designed; synthetic parameters were duly optimized, and powders were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), Fourier transform infrared spectroscopy (FTIR),1H NMR, and Raman spectroscopy. An in-depth analysis of powder properties and electrochemical behavior of the fabricated SSLM cells revealed that impurities present in LLZO significantly facilitated electrochemical cell performances. Such a combination of the engineered LLZO impregnated with the SIL enabled the plating and stripping cycles in Li symmetric cells with up to 200 h of operation at a constant current density of 0.05 mA center dot cm-2 avoiding short circuit. The critical current density (CCD) was found to be 450 mu A cm-2, which is significantly higher than the other reported CCD values for pristine LLZO. The post-electrochemical study revealed that transgranular lithium dendritic growth, a genuine problem in SSLMBs, was impeded to a significant extent by the engineered LLZO and an in situ formed phase, Li0.5Al0.5La2O4, at grain boundaries during cycling. The multicathode compatibility tests as performed (Li/LLZO-SIL/LMO, Li/ LLZO-SIL/LFP, and Li/LLZO-SIL/NMC111) exhibited that morphologically altered LLZO with the SIL interface is compatible with most of the commercial cathodes. The study thus envisaged that the engineered LLZO solid electrolyte impregnated with the SIL can exert a synergistic effect to enhance faster Li-ion conduction as well as resistance to Li dendritic growth, providing a path for developing high-performance SSLMBs
Highly efficient and recyclable quaternary Ag/Ag3PO4-BiOBr-C3N4 composite fabrication for efficient solar-driven photocatalytic performance for anionic pollutant in an aqueous medium and mechanism insights
No full textA simple chemical precipitation route to synthesize the quaternary composite under mild conditions is reported. The quaternary composite photocatalyst Ag/Ag3PO4-BiOBr-C3N4-1 band gap was tuned to 0.56 eV by varying the amount of C3N4 for efficient photocatalytic performance. The as-prepared photocatalysts were characterized by XRD, XPS, TEM, EDAX, BET, EIS, and UV-Vis DRS spectroscopy. The degradation of reactive red (RR 120) under visible-light illumination were evaluated. The surface plasmon resonance (SPR) effect of Ag nanoparticles enhances the absorption and utilization of visible light. The Ag/Ag3PO4-BiOBr-C3N4 composite exhibited 92.6% degradation efficiency with the removal rate 0.042 min-1 which is 5.2, 2.7 and 2.5 times greater compared to pristine Ag/Ag3PO4, BiOBr and C3N4 particles. The active species holes (h+), superoxide (center dot O2-) and hydroxyl (center dot OH) radicals were responsible for the degradation process. The 4 times of cycle experiments proved the relatively high stability of the synthesized photocatalyst. The quaternary Ag/Ag3PO4-BiOBr-C3N4 heterojunction can endorse enhanced redox capability. The faster interfacial transport was validated, for quaternary photocatalysts using the EIS Nyquist plot. The work has driven a significant guidance in designing photocatalysts with surface plasmon effect
Hydrothermal synthesis of defect-induced pristine alpha-NaCe(WO4)(2): a novel material for solid state lighting and gas sensing
No full textTriclinic NaCe(WO4)(2) with oxygen monovacancies and divacancies has been successfully prepared via a facile cetyltrimethyl ammonium bromide (CTAB)-assisted hydrothermal technique. X-ray diffraction, scanning electron microscopy, and transmission electron microscopy have been employed to determine the unit cell and microstructure of the NaCe(WO4)(2). The oxygen vacancies, structural distortion etc. have been investigated using Fourier-transform infrared, Raman and X-ray photoelectron spectroscopies. The synthesized samples exhibit an intense blue emission at 434 nm due to the 5d-4f transition of Ce3+ within the CeO8 dodecahedra, while the emission at 485 nm is ascribed to the 5d-4f transition within CeO7. It has also been identified that two emissions at 451 and 520 nm come from CeO6. Additionally, we find that the temperature of the hydrothermal reaction guides the formation of CeO7 and CeO6. In contrast to a previous ethylenediamine tetraacetic acid (EDTA)-assisted synthesis of NaCe(WO4)(2) that results in a predominant green emission, our samples exhibit strong violet emissions indicating that less CeO7 and CeO6 is formed when using CTAB. We have also conducted ab initio calculations using density-functional theory, which reveals that the valence and conduction bands comprise of the O(2)p orbitals and a O(2)p-Ce 5d hybridization, respectively. The Ce(5)dz(2), 5dyz and 5dxz orbitals mostly facilitate the 5d-4f transition within the CeO7 and CeO6 polyhedra. Commission Internationale de I'Eclairage coordinates are found in the blue region with a correlated color temperature (CCT) of similar to 7715 K indicating the potential for a-NaCe(WO4)(2) to be used in cold solid state lighting applications. Finally, we also observe that the oxygen vacancies can act as active centers for the adsorption of molecular oxygen, which in consequence leads NaCe(WO4) 2 to have gas sensing properties
Structural characterization and photoelectrochemistry of coordination polymer of Pb(II)-naphthyl-isonicotinohydrazide Schiff base
No full textAn organic-inorganic hybrid Pb(II)-based 1D coordination polymer, {Pb(NSB)NO3.DMF]}(n) (CP) (H-NSB = isonicotinic acid (2-hydroxy-naphthalen-1-ylmethylene)-hydrazide; DMF = N,N-dimethylformamide), is structurally characterized by single crystal X-ray diffraction measurement and other spectroscopic data. The structure shows that the ligand, H-NSB serves as a monoanionic tetradentate N2O2 chelating linker of mu(3)-kappa N,kappa O;kappa O,N,O type, where kappa O (phenolato-O) brings two Pb(II) centres together and the tridentate NO2 unit chelates (kappa O,N,O) with one Pb(II) unit followed by its pyridyl-N links (kappa N) with nearest Pb(II) centre for propagating as a seven coordinated distorted pentagonal bi-pyramidal PbO5N2 core (one O donor comes from DMF and another O from NO3-). Thus, 1D chain is constructed that is thermally stable. The noncovalent interactions (pi center dot center dot center dot pi, H-bonding and C-H center dot center dot center dot pi) amongst the 1D chains make supramolecular 3D architecture. The Hirshfeld surface analysis approves the existence of several noncovalent interactions for the formation of 3D network. The reasonable band gap of 3.04 eV for the CP lies in the semiconducting region, which simulates fabrication of photoelectrochemical device with high magnitude of photocurrent (current density: similar to 2.5 mu A cm(-2)). Mott-Schottky analysis indicates the n-type semiconducting behaviour, and chronoamperometry plot also shows the stability of the material against photo corrosion. Present elucidation would decipher an encouraging pathway for harvesting next-generation energy resources based on a novel Pb(II)-naphthyl-isonicotinohydrazide Schiff base-based CP
Exploration of 1D-2D LaFeO3/RGO S-scheme heterojunction for photocatalytic water splitting
No full textSustainable energy innovation is spearheading the way to achieve decarbonisation through commercially viable and highly competitive renewable technologies for green hydrogen. Photocatalytic water splitting has received global attention, as it promotes the direct conversion of solar energy to chemical energy and hydrogen production. Lanthanum orthoferrite (LaFeO3) has been selected due to its narrow bandgap perovskite-oxides (ABO(3)) type nature, low cost and high chemical stability but it is limited with fast charge recombination. To circumvent its constraint of fast charge recombination, an efficient graphene-based nanocomposite has been prepared by employing reduced graphene oxide (RGO) nanosheets as charge separators for visible light driven photocatalytic water splitting. Here, we present a thorough physical and spectroscopic characterization of the Lanthanum orthoferrite/Reduced Graphene oxide (LaFeO3/RGO) nanocomposites, and investigate its photocatalytic and photoelectrochemical performance. The photocurrent density of the nanocomposites demonstrated similar to 21 times higher in comparison to pure LaFeO3. The as-prepared nanocomposites have been successfully used as photocatalysts for H-2 generation through water reduction under visible light. A significant enhancement in H-2 generation has been recorded for nanocomposites (similar to 82 mmol g(-1) h(-1)) as compared to that of bare LaFeO3 (similar to 9 mmol g(-1) h-(1)) which is among the highest values obtained using noble-metal-free graphene-based photocatalytic nanocomposites. This work offers a facile approach for fabricating highly efficient 1D-2D heterostructure for photocatalysis application. Crown Copyright (c) 2023 Published by Elsevier Ltd on behalf of Hydrogen Energy Publications LLC. All rights reserved
Room-Temperature High-Performance Trace Level Acetone Sensor Based on Polypyrrole Nanotubes
No full textRecently, precise detection of VOCs in particular acetone, ammonia alcohol has attracted huge attention for industrial safety, monitoring of environment and human health. In this article we have reported for a polypyrrole nanotube (PPNT)-based chemiresistive sensor for the selective detection of trace acetone vapour at room temperature (25 & DEG;C). Polypyrrole (PPy) nanoparticles with different morphologies, viz. nanotubes, nanowire, and globular were synthesized using methyl orange (MO), cetyltrimethyl ammonium bromide (CTAB), and pure polypyrrole as the growth template. The as synthesized powders were exploited to fabricate Taguchi-type thick-film sensors. The synthesized powders and fabricated sensors were characterized by multiple sophisticated techniques, such as, XRD, FTIR, Raman spectroscopy, SEM, EDS, UV-VIS spectroscopy, optical non-contact profilometry, and current-Voltage (I-V) measurement. It is observed that the PPNT sensor shows the highest response to trace acetone vapour with a lower detection limit of 500 ppb at room temperature (25 & DEG;C) and quick response (& SIM;5.4 sec) and recovery (& SIM;73.94 sec) times. Achieved enhanced sensing behaviour can be attributed to formation of hydrogen bond between acetone and PPy. Combined with room temperature sensing, good stability, repeatability, produce sensor may find application in various sensing fields
Design and realization of a femtosecond-laser-inscribed fiber Bragg grating for accurate measurement of liquid level and liquid density
No full textAn exceptionally sensitive liquid level and density sensor system using Femtosecond-Laser-Inscribed Fiber Bragg Gratings is designed and demonstrated utilizing the basic Archimedes' Law of Buoyancy. The sensor works based on principles of Archimedes' law of buoyancy and basic strain sensitivity of Fiber Bragg Grating (FBG). A cylindrical mass of 22.5 cm long is suspended from one end of the FBG and whereas the other end of the fiber is fixed. The mass is partially immersed into the liquid under consideration to measure the liquid level as well as liquid density. Following Archimedes' law of buoyancy, the relative weight of the suspended mass gets reduced and the corresponding shift in Bragg wavelength is measured using an interrogator connected at the fixed end of the sensor lead fiber. The relative weight of the immersed mass also depends on the liquid density. Therefore, a change in liquid density also is reflected by the shift in Bragg wavelength. The system can be calibrated to measure the accurate liquid level and liquid density. A liquid (water) level measurement sensitivity of 5.47 to 5.60 pm/mm is achieved using the system under three times of consecutive experiments which is very close to the simulated value (5.9 pm/mm). A density measurement sensitivity of - 0.71 nm/(gm/cm3) is calculated in this system and experimentally achieved sensitivity is - 0.7 nm/(gm/cm3). The LOD (limit of detection) was also found to be 1.008 gm/cc for the density measurement and the average error during the measurement was 0.0021 nm/(gm/cm3).It is also shown that the density measurement sensitivity is highly dependent on the amount of immersed portion of the suspended mass and more amount of immersed mass is desirable for better sensitivity