HRTEM Studies Research Articles

Mesoporous Fe2O3-TiO2 Integrated with Plasmonic Ag Nanoparticles for Enhanced Solar H2 Production.

Present work describes a sol-gel assisted one-pot synthesis of mesoporous Fe₂O₃-TiO₂ nanocomposites (TiFe) with different Ti:Fe ratios, and fabrication of Ag-integrated with TiFe nanocomposites (TiFeAg) by a chemical reduction method and demonstrated for high solar H2 generation activity in direct sunlight. Enhanced solar H2 production is attributed to the light absorption from entire UV+Visible region of solar spectrum combined with Schottky (Ag-semiconductor) and heterojunctions (TiO2-Fe2O3), as evidenced from HRTEM and various characterization studies. TiFeAg-2 thin film (1 wt% Ag-loaded TiFe-4) displayed the highest activity with a solar H2 yield of 7.64 mmol h⁻¹g⁻¹, which is 48 times higher than that of bare TiO₂ and 5 times higher in thin film form compared to its powder counterpart. Schottky and heterojunctions formed at the interface efficiently separate the charge carriers and increase the hydrogen production activity. The highest H2 production activity of TiFeAg-2 is partly attributed to the heterogeneous distribution of Fe3+ and metallic Ag-species with relatively high Ag/Ti surface atomic ratio. A plausible photocatalytic reaction mechanism on TiFeAg nanocomposite may involve the direct electron transfer from both Fe2O3 and TiO2 to Ag nanoparticles which are subsequently utilized for the reduction of H+ to H2.

HRTEM Study of Desulfurization of Pt- and Pd-Rich Sulfides from New Caledonia Ophiolite

Oxygen-bearing platinum group minerals (O-bearing PGMs) are intergrown with base metal sulfides (BMS, e.g., pentlandite–[NiFe]9S8) within fractures in chromite grains from chromitite bodies on Ouen Island, New Caledonia. These PGMs are hosted in chlorite and serpentine, which formed during serpentinization of olivine and pyroxene. The O-bearing PGM grains are polygonal, show microfracturing (indicating volume loss), and contain Pt-Pd-rich sulfide remnants, suggesting pseudomorphic replacement of primary (magmatic) sulfides. They display chemical zonation, with Pt(-Pd-Ni-Fe) relict sulfide cores replaced by Pt-Fe-Ni oxidized alloy mantles and Pt-Cu-Fe(-Pd) alloy rims (tulameenite), indicating desulfurization. The core and mantle show a nanoporous structure, interpreted as the result of coupled dissolution–reprecipitation reactions between magmatic sulfides and low fO2–fS2 serpentinite-related fluids, probably formed during olivine transformation to serpentine + magnetite (early stages of serpentinization). This fluid infiltrated magmatic sulfides (PGE-rich and BMS), degrading them to secondary products and releasing S and metals that were accommodated in the mantle and rim of O-bearing PGMs. Upon olivine exhaustion, an increase in fO2 might have stabilized Pt-Fe-O compounds (likely Pt0/Pt-Fe + Fe oxyhydroxides) alongside Ni-Fe alloys. Our results show that post-magmatic desulfurization of primary sulfides produces complex nano-scale intergrowths, mainly driven by changes in the fluid’s physicochemical properties during serpentinization.

Superconductivity and surface structures in iron-doped bulk compound Bi2Sr2Ca2(Cu0.99Fe0.01)3O10+δ

Nowadays, researchers are extremely fascinated with the study of the doping effects of nanostructures of different materials, sizes and concentrations in high [Formula: see text] superconductors. This paper presents the presence of nanorods (N) structures, which have not previously been observed in the bulk HTSCs materials, and the influence of Iron doping in Bi-2223 superconductor using composition Bi2Sr2Ca[Formula: see text](Cu[Formula: see text]Fex)nO[Formula: see text], ([Formula: see text]) for ([Formula: see text] and 0.01). The composition is prepared through a solid state route (SSR). The obtained samples are characterized with XRD, FESEM with EDX, HR-TEM and FTIR, and categorized into two samples ([Formula: see text]) and ([Formula: see text]) Bi2Sr2Ca2Cu3O[Formula: see text], and Bi2Sr2Ca2(Cu[Formula: see text]Fe[Formula: see text])3O[Formula: see text], respectively, which show Lattice dimensions [Formula: see text][Formula: see text]Å, [Formula: see text][Formula: see text]Å, [Formula: see text][Formula: see text]Å and [Formula: see text][Formula: see text]Å, [Formula: see text][Formula: see text]Å, [Formula: see text][Formula: see text]Å with Orthorhombic crystal structure, respectively. The FE-SEM micrographs show plate-like layered structures and (N) in the samples, which are uniformly distributed. The obtained size of crystallite nanoparticles is 2[Formula: see text]nm–100[Formula: see text]nm, calculated by the Scherrer method, and verified with HR-TEM data. The HR-TEM study also confirmed the layered form in the orthorhombic phase. The FESEM-EDX energy peaks in the spectrum confirm the presence of the elements in both samples ([Formula: see text]) and ([Formula: see text]). The HRTEM-EDX confirms the extant iron in the sample in the form of (N). The FTIR bond stretching 1630.89[Formula: see text]cm[Formula: see text] and 1629.657[Formula: see text]cm[Formula: see text] of the samples ([Formula: see text]) and ([Formula: see text]), respectively, confirms the superconductor bismuth-based 2223 phase, respectively. The electrical resistivity study of ([Formula: see text]) and ([Formula: see text]) samples shows the critical temperature ([Formula: see text]) of 63.083[Formula: see text]K and 22.8195[Formula: see text]K, respectively. The onset temperature for both samples is measured at 115.1785[Formula: see text]K and 68.314[Formula: see text]K, which represent the Bi-2223 phase. The magnetoresistance is obtained at low temperatures by a physical properties measurement system (PPMS) and with the increasing order of applied magnetic field from 0 to 12 Tesla, an increase in the resistivity in the pure sample ([Formula: see text]) and also a decrease in transition temperature are observed. These results are as similar to those obtained in the Bi-2223 Superconductor. The results show the growth of nanoparticles in the iron-doped Bisco superconductors.

Spatially-Resolved EELS Analysis of Surface Species on Metallic Lithium for the Development of Next Generation Li-Batteries.

Metallic Li is considered one of the most attractive anode candidates for solid-state battery technology as well as for the next generation Li-ions batteries [1,2] due to its ultrahigh theoretical specific capacity (3860 mAhg−1)[3]. However, several technical issues hinder its application as anode material. The widespread commercial usage of Li metallic sheet will necessitate a much better understanding of its microstructure and chemical nature.Metallic lithium is highly sensitive to hydrogen, oxygen, nitrogen, and carbon dioxide, which are the major components of wet air, and are likely to form rapidly LiOH, Li2O, Li2O2, Li3N, and Li2CO3 species [4] when exposed to air and/or moisture. It has been shown that this surface passivation layer has a direct impact on the anode interface resistance in solid state batteries [5]. Because of the nature of Li, very few works have looked directly at the surface chemical structure [6]. XPS and SIMS are normally used to study the nature and thickness of this passivation layer. However, these techniques do not allow to directly observe the nature and thickness of this layer. Direct observation, using TEM, would thus be much better.Because of the very high surface reactivity and the low hardness of Li, it is very difficult to prepare thin sample from a precise Li sheet for direct TEM observations and chemical analysis of the material structure and surface chemical nature. In this presentation we will show the direct HRTEM study of the surface chemical nature of metallic Li sheets. We have used a Hitachi air-protection cryogenic FIB holder to prepare thin Li samples and study the surface chemistry using Spatially-Resolved EELS (SR-EELS). The thin samples were prepared from different Li sheets using FIB (NB5000 from Hitachi) with the sample temperature at ~ -90 °C. The samples were transferred under vacuum using the same holder into a Hitachi HF-3300 cold FEG E-TEM for EELS analysis at low temperature without air contact.SR-EELS was done using a high-resolution GIF system (Gatan Quantum ER) for the rapid acquisition of the Li-K-edge, O-K-edge and C-K-edge respectively. Using this technique, it is possible to directly observe the different chemical variation in the passivation layer and its variation from sample to sample.[1] R. May, K. J. Fritzsching, D. Livitz, S. R. Denny, and L. E. Marbella ACS Energy Letters 6 (4), 1162-1169 (2021)[2] Y. Zhang, T.-T. Zuo, J. Popovic, K. Lim, Y.-X. Yin, J. Maier, Y.-G. Guo, Materials Today 33 , 56-74 (2020)[3] X.-B. Cheng, C.-Z. Zhao, Y.-X. Yao, H. Liu, Q. Zhang, Chem 5, 74-96 (2019)[4] D. Jeppson, J. Ballif, W. Yuan and B. Chou, 1978. Lithium literature review: Lithium’s properties and interactions. Richland, Washington: Hanford Engineering Development Lab[5] S.-K. Otto, T. Fuchs, Y. Moryson, C. Lerch, B. Mogwitz, J. Sann, J. Janek and A. Henss, ACS Appl. Energy Mater. 4, 12798−12807 (2021).[6] N. Brodusch, K. Zaghib and R. Gauvin, Micros. Res. & Tech. 78, 30-39 (2015)

Green Synthesis, Characterization, and Catalytic Applications of CuO Nanoparticles Using Prosopis Cineraria Seed Extract

Abstract The current study used a seed extract of Prosopis cineraria as a stabilizing and reducing agent to produce CuO nanoparticles via an easy, low-cost, affordable, and environmentally friendly synthesis process. The formation of copper oxide nanoparticles and the maximum absorbance of the CuO nanoparticles produced in the solution at 565 nm were verified by UV-vis. Copper oxide nanoparticles were found to have secondary metabolites on their surface, as shown by a distinctive Cu-O stretching band at 532 cm−1, which confirmed the reduced Cu2+ ions in copper oxide nanoparticles. This was confirmed by FTIR analysis. The XRD analysis confirmed the produced copper oxide nanoparticles’ monoclinic crystalline nanostructure with an average particle size of 34 nm. The phytonutrients in Prosopis cineraria seed extract stabilized and reduced copper, as demonstrated by the existence of copper and oxygen atoms at 85.2% and 12.5%, respectively, as demonstrated by SEM-EDX analysis. According to the HR-TEM study, copper oxide nanoparticles with a mean size of 18 nm are spherical in shape and well distributed. Prosopis cineraria seed extract-derived copper oxide nanoparticles were utilized as a catalyst in the Ullmann process to produce diphenyl ether. CuO nanoparticles produced by Prosopis cineraria seed extraction as a catalyst yielded 91% diphenyl ether. The results showed that a more ecologically friendly way of synthesizing copper oxide nanoparticles with great homogeneity of particle sizes could be achieved using seed extract. This work aims to facilitate heterogeneous catalysis from CuO nanoparticles utilising Prosopis cineraria seed extract. Overall, this technique offers several advantages, like high yields at fast reaction times, and low catalyst loading are just a few of this approach’s many benefits.

Palladium immobilized on functionalized halloysite: A robust catalyst for ligand free Suzuki–Miyaura cross coupling and synthesis of pyrano[2,3-c]pyrazole motifs via four component cascade reaction and their in-silico antitubercular screening

This research introduces a novel organically functionalized halloysite-supported palladium catalyst, HMF-EDA-TMS@HAL-Pd(II) that was synthesized and thoroughly characterized using various analytical techniques like HR-TEM, FEG-SEM, EDX, XPS, FTIR, XRD, TGA, ICP-AES, EXAFS and DFT studies. The catalyst exhibited exceptional performance in Suzuki–Miyaura cross coupling reactions, demonstrating high efficiency and reusability up to seven cycles in aqueous ethanol medium. Motivated by its promising catalytic activity, we extended our investigation to explore its applicability in the synthesis of pyrano[2,3-c]pyrazole motifs via a four-component cascade reaction affording the desired products in good to excellent yields with broad substrate scope under green reaction conditions. In-silico antitubercular screening of pyrano[2,3-c]pyrazole motifs against DprE1 enzyme have shown promising results with inhibition constants ranging between 0.030 and 0.1 μM for compounds 5b, 5k and 5 l. This protocol has the advantages of wide substrate scope, high yield, excellent functional group tolerance, high efficiency and environmental benign procedure. These findings emphasized the catalyst's versatility and potential in diverse organic transformations, highlighting its importance in advancing sustainable synthetic methodologies.

Mo-modified Pt/C electrocatalyst prepared by the catalytic decomposition of molybdenum peroxo-complexes for the hydrogen oxidation reaction with enhanced CO tolerance

Commercial 20 % Pt/C catalyst was modified by molybdenum via catalytic decomposition of peroxocomplexes of molybdenum with the subsequent reduction of the Pt2Mo1/C precursor in H2 flow at 600 °C. The detailed HRTEM, EDX, XRD and XPS studies showed that amorphous molybdenum oxide was deposited on Pt particles surface and partially on carbon support. After reduction of the Pt2Mo1/C precursor, the substantial Mo fraction merges the structure of Pt particles thus forming PtMo alloy with reduced lattice parameter, while the rest of molybdenum covers the surface of PtMo particles as MoO3. The presented method of Mo-modification of Pt-based catalysts provides rather simple way to vary Pt:Mo molar ratio. Electrochemical study revealed that the amount of the surface MoO3 plays a key role in the CO tolerance of the PtMo/C catalyst. As prepared Pt2Mo1/C precursor is 15 times superior to the Pt/C catalyst in the CO-tolerance. After reduction, the Pt2Mo1/C electrocatalyst exhibits extremely high CO-tolerance, more than 100 times higher than that of the pristine commercial platinum catalyst.

Copper-Based Metal–Organic Framework: Synthesis, Characterization and Evaluation for the Hydrogenation of Furfural to Furfuryl Alcohol

AbstractA novel Cu-MOF was synthesized at room temperature from commercially available and inexpensive reagents. The pre-catalyst was characterized using X-ray photoelectron spectroscopy, high-resolution transmission electron microscopy, inductively coupled plasma-optical emission spectroscopy, Fourier transform-infrared spectroscopy, powder X-ray diffraction, Brunauer-Emmet-Teller (BET) and scanning electron microscopy-energy dispersive X-ray spectroscopy. The Cu-MOF was characterized as microporous material with BET surface area and pore volume of 7.47 m2/g and 0.27 cm3/g, respectively, and is stable in most solvents. The MOF was evaluated as a heterogeneous catalyst for the hydrogenation of furfural to furfuryl alcohol (FA). Cu-MOF exhibited a high conversion of FF (76%) with selectivity towards FA (100%) at 140 °C, 50 bar for 24 h. The MOF was reused four consecutive times with a loss in catalytic performance. The decrease in catalytic activity could be attributed to the formation of inactive Cu(0) as revealed by HR-TEM and XPS studies. The HR-TEM of spent Cu-MOF showed a uniform particle size diameter of 3.5 nm. This work is significant in providing new strategies for the design and fabrication of highly selective MOF catalysts for the FF upgrading.

Atomic-scale bonding strength and failure mechanisms of HfC/Ni/Ni3Al interfaces on low-index crystal planes: A combined HRTEM and first-principles study

The carbide/matrix interface in superalloys is susceptible to cracking under mechanical stress, yet the failure mechanisms require further investigation. The cohesive strength and stability of 32 interface models, including HfC(001)/Ni(001), HfC(011)/Ni(001), HfC(111)/Ni(001), HfC(001)/Ni3Al(011), and HfC(111)/Ni3Al(111) within the DZ125 superalloys, were investigated using first-principles calculations and experimental methods. The results indicate that the majority of interfaces demonstrate negative adhesion work (Wad), indicating instability. However, Bridge4 model in HfC(001)/Ni3Al(011) show higher Wad and lower interface energy, suggesting improved stability. The interfacial cohesion is attributable to strong Ni-C covalent bonds. But interfacial fracture toughness results reveal that the majority of models are more susceptible to fracture at the interface. Fracture morphology analysis from tensile tests at room temperature and endurance tests at 760 °C/725 MPa confirms that cracks primarily initiate at the carbide/matrix interface. This study suggests that introducing Ta atoms could improve interface strength, as Ta-rich carbides reduce interfacial energy while increasing elastic energy, resulting in the formation of skeletal structures. The relationship between Hf-rich and Ta-rich carbides and their respective morphology was investigated. The findings provide insights into the failure mechanisms of carbide/matrix interface and offer theoretical guidance for enhancing interface strength in superalloy applications.

Exploring the diverse applications of sol–gel synthesized CaO:MgAl2O4 nanocomposite: morphological, photocatalytic, and electrochemical perspectives

A nanocomposite of CaO:MgAl2O4 was synthesized through a straightforward and cost-effective sol–gel method. The investigation of the novel CaO:MgAl2O4 nanocomposite encompassed an examination of its morphological and structural alterations, as well as an exploration of its photocatalytic activities and electrochemical characteristics. XRD analysis revealed a nanocomposite size of 24.15 nm. The band gap, determined through UV studies, was found to be 3.83 eV, and scanning electron microscopy (SEM) illustrated flake-like morphological changes in the CaO:MgAl2O4 samples. TEM, HRTEM, and SAED studies of a CaO:MgAl2O4 nanocomposite would reveal important details about its morphology, crystallography, and nanostructure. Photocatalytic activity was quantified by studying the degradation of Acid Red-88 (AR-88) dye in a deionized solution, achieving a 70% dye degradation under UV irradiation in 120 min. Plant growth examinations were carried out using dye degraded water to test its suitability for agriculture. The electrochemical energy storage and sensing applications of the prepared nanocomposite were examined using CaO:MgAl2O4 modified carbon paste electrode through cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). In conclusion, the synthesized CaO:MgAl2O4 nanocomposite demonstrated promising morphological and structural characteristics, efficient photocatalytic activity, and potential applications in electrochemical energy storage, highlighting its versatility for various technological and environmental applications.Graphical abstract

Synthesis of undoped and mixed binary transition metals (Ni-Co)-doped cupric oxide nanostructures: Structural characteristics, optical behavior, and biological activity

In this work, co-precipitation-assisted undoped and various concentrations (1%, 3%, and 5%) Ni-Co-doped CuO nanostructures have been synthesized to test the biomedical applications. The structure, optical band gap, zone of inhibition width, hemocompatibility, and free radical scavenging activity of the CuO are significantly varied by introducing various concentrations of co-dopants compared to the undoped CuO. The single phase of monoclinic and heterogeneous crystal systems (monoclinic CuO, hexagonal Co, cubic NiO, and Co3O4) for undoped CuO and all Ni-Co-doped CuO samples was identified by the powder XRD tools. Microstructural properties were tuned in each dopant concentration of Ni-Co in the CuO, which confirmed through FE-SEM analysis. Heterogeneous structures (spherical particles/sheet-like particles) were noticed in the HR-TEM studies of 5% Ni-Co-doped CuO nanostructures. Synthesized compounds related to the elements (Cu, O, Co, and Ni) were traced with the help of the EDX and XPS study. The photoabsorption spectra and optical band gap values of the undoped CuO and co-doped CuO samples were significantly varied. Antimicrobial studies of the undoped CuO and Ni-Co co-doped CuO against E. coli and S. mutans bacterial strains were performed, and their outcomes of the zone of inhibition (ZOI) values have been discussed in detail. The synthesized undoped and various concentrations of CuO particles were taken to investigate their compatibility via hemolytic study. Hemolysis results showed that both the synthesized undoped CuO and Ni-Co doped CuO nanostructures are highly hemocompatible. In addition, compatibility natures are varied with increasing concentrations from 1% to 5% Ni-Co dopant in the CuO samples. The DPPH assay was employed to evaluate the antioxidant properties of the synthesized particles by determining their free radical scavenging (FRS) activity percentages. It was observed that Ni-Co-doped CuO exhibited better antioxidant properties than undoped CuO due to the higher FRS percentage.

Influence of Nitrogen-Doped Carbon Dots on H• Radical-Mediated Au-H Formation in the Hydrogenation of 4-Nitrophenol Using NCDs-Au Nanohybrids.

The hydrogenation of 4-nitrophenol using carbon dot-stabilized gold (Au) nanoparticles is well-studied, with Au-H species known to catalyze the reaction. However, the impact of specific nitrogen moieties in nitrogen-doped carbon dots on Au-H formation and catalytic activity remains unexplored. These nitrogen species, acting as surface ligands, may influence the catalytic properties through the generation of Au-H species via H• radicals. In this regard, modulation of the catalytic properties of Au nanoparticles has been explored by conjugating their surface with nitrogen-doped carbon dots (NCDs). Three distinct nanohybrid formulations comprising NCDs and Au nanoparticles (i.e., NCDs-Au) have been prepared, where the NCDs were derived from different carbon sources (e.g., citric acid and l-malic acid) and varying mole ratios of the nitrogen source (i.e., urea). The impact of NCDs on Au nanoparticle-mediated catalysis has been investigated using the model reaction of hydrogenation of 4-nitrophenol (4-NP) in the presence of NaBH4. The fractions of different nitrogen species (such as pyrrolic, pyridinic, and amidic) in the different NCDs-Au nanohybrids were quantified through XPS analysis, and their roles in catalytic performance have been studied. Further, the size, shape, crystallinity, defects, and exposed facets of the NCDs-Au nanohybrids have also been assessed (through XRD, HRTEM, and Raman studies), and their structure-activity relationships have been corroborated. The hydrogenation of 4-NP is proposed to happen through the formation of gold-hydride (Au-H) species facilitated by H• radicals, as confirmed by EPR analysis. The NCDs-Au nanohybrid, synthesized from NCDs derived from a 1:3 molar ratio of l-malic acid and urea (MU13-Au), exhibits superior catalytic efficiency with a rate constant of 1.013 min-1, attributed to its abundant defects and a notably high relative content of catalytically favorable pyridinic nitrogen species compared to other tested nanohybrids.

Solid Handmade Ternary Coinage Metal Mentors for Organic Bond-Making and Bond-Breaking Applications.

A comparative approach is employed for the novel synthesis of a magnetically recoverable ternary nanocomposite consisting of g-C3N4-supported Fe3O4 decorated with coinage metals (Au, Ag, and Cu). This synthesis is achieved through a straightforward and convenient one-step grinding protocol. In situ, the nanoparticles were grown on the g-C3N4-assist Fe3O4 matrix (GCFM), and the agglomeration of these nanoparticles on the matrix creates a pathway for the formation of the nanocomposite (NC). The as-formed CNC was confirmed with the help of characterization analyses, namely XRD, FT-IR, HR-TEM, FE-SEM, XPS, VSM, UV-vis, and NMR studies. Together with NPs and GCFM, with the quantum consequence, the activity of the NC shows better electron transfer via transfer of electrons, which grabs tremendous attention toward it, resulting in enhanced plausible photocatalytic degradation toward pharmaceutical compounds, dyes, and anthropogenic pollutants. The activity of the C-NC hikes at 88% for ciprofloxacin (CX) and 90% for paracetamol (PM); furthermore, the activity of the C-NC hikes at 88% and 87% for xylene Cyanol FF (XCF) and malachite green (MLG), respectively. Interestingly, an added advantage is the formation of a C-C bond (homocoupling reaction) in phenylboronic acid (PA) via a greener solvent under ambient conditions. The yield percentage of the conversion product shows satisfactory results, and its reproducibility was good for the prepared ternary NC. The conversion treatment of anthropogenic pollutants, namely 4-nitrophenol, grasps a high percentage (98%). In addition, the NC shows good activity toward both types of bacteria. The reproducibility of the composite also shows virtuous activity against pharmaceutical as well as toxic contaminants. The as-prepared CNC was specifically engineered to perform both bond formation and bond cleavage of organic molecules under ambient conditions for multiple cycles.

Nanoarchitectonics of hydrothermal carbonized sugarcane juice-derived biochar for high supercapacitance and dye adsorption performance

Here, we report the exfoliation of micron-sphere biochar to a few layers using the conventional KOH activation process. Micron-sphere biochar is obtained from hydrothermal carbonization (HTC) of sugarcane juice (Saccharum officinarum). HR-TEM and Raman spectroscopy studies revealed the conversion of micron-sphere biochar (MSB) to a few layers of biochar (FLB) in the activation process. BET characterization revealed FLB with a high surface area of 681.21 m2/g having mesopores. Consequently, an electrochemical study demonstrated excellent supercapacitor performance with a specific capacitance of 964.5 F/g and an energy density of 33.11 Wh/kg at a maximum power density of 936 W/kg. Batch adsorption studies showed rapid Methylene blue (MB) dye adsorption in 10 min. The equilibrium data analysis indicated the Langmuir adsorption isotherm with a correlation coefficient of 0.99. Evaluation of the kinetic models suggests that pseudo-second-order kinetics is the most appropriate model, implying that the adsorption of MB dye is primarily due to chemisorption. These findings suggest a Nanoarchitectonics of biochar into a few layers using traditional KOH activation, suitable for various applications.

Antitubercular nanocarrier monotherapy: study of in-silico molecular docking and in-vitro efficacy of repurposed antiviral drug

Abstract There has to be a breakthrough in tuberculosis (TB) treatment to address issues with drug resistance, patient noncompliance, and dosage frequency. We produced durable therapeutic nanocarriers (NCs) and tested their efficiency in-vitro in macrophages infected with Mycobacterium tuberculosis. Our goal was to decrease adverse effects linked to systemic drug distribution and improve drug concentration at the target site. There are multiple pathways by which antiviral medications induce renal failure. Several novel drugs have been shown to cause direct renal tubular toxicity through their distinct impacts on kidney epithelial cells. In this present study the in-silico docking studies were performed and the silver nanoparticles of the antiviral drug Entecavir was prepared and characterized by using SEM and HR-TEM studies. The prepared nanoparticles were evaluated for its anti-tubercular activity by in-vitro and the results showed the repurposed antiviral drug showed remarkable anti-tubercular activity. There is mounting evidence that the repurposed antitubercular drug Entecavir is a viable new option for treating tuberculosis.

Structural, spectroscopic and improved photoelectrochemical properties of TiO2/C composites with anatase/brookite matrix, prepared by air-thermolysis of microspherical titanium glycolate

X-ray powder diffraction, Raman spectroscopy, HRTEM, electron diffraction and differential thermal analysis methods were used to study structural and spectroscopic properties and thermal stability of the products obtained by air-thermolysis of Ti-glycolate in the temperature range 300–450°С. TiO2/C composites were obtained, which have anatase/brookite matrix with a variable degree of crystallinity and contain different contents of brookite and free polymeric-like carbon with COO− groups. It was found that the residual content of carbonaceous component and the intensity of exothermal decomposition of Ti-glycolate have an effect on the formation of brookite-rich TiO2 matrix. Correlations between the phase composition and the free carbon content suggest that during crystallization brookite/carbon nanoparticles are more stable than anatase/carbon nanoparticles. PEC tests demonstrated that the composite photoanode, which has the greatest degree of crystallinity, the optimal carbon content and is most enriched with brookite, exhibits the greatest incident photon-to-current conversion efficiency (IPCE), and its IPCE peak value is twice as great as the IPCE peak value for Degussa P25. The increased IPCE value is associated with the preferable formation of carbon/brookite/anatase heterostructures. The carbon component has an optical gap of approx. 1.1 eV, and at the optimal contents it ensures efficient photogeneration and transfer of electrons into the conduction band of brookite and then into the conduction band of anatase. HRTEM study demonstrated the formation of such heterostructure with anatase/brookite heterojunction.

Fluorescent ‘turn-on’ porphyrin CQD nanoprobes for selective sensing of heavy metal ions

In this work, a one-step pyrolysis technique is employed to synthesize porphyrin based carbon quantum dots (Porp-CQDs). The as-synthesized Porp-CQDs permit fluorescence “on/off” strategies to detect heavy metal ions. The structural formation of the Porp-CQDs with optical properties is confirmed through characterization techniques like UV–visible, fluorescence spectroscopy, HR-TEM, AFM, X-ray diffraction, and FT-IR studies. Porp-CQDs have an average particle size of 2.4 nm and a spherical shape with a semi-crystalline appearance. The excitation wavelength appears at 434 nm corresponding to the π-π* electronic transition of the soret band between the HOMO and LUMO energy levels with emission at 670 nm. The CV curves of the modified Porp-CQDs/GCE at a scan rate of 10 mV s−1 and Porp-CQDs/GCE exhibits good oxidation and reduction peaks at 1.43 V and − 0.36 V, respectively. The metal ion sensing mechanism is driven through the structure of the porphyrin core which makes it easy to form transition complexes with various metal ions in the central cage of the system. Porphyrins tagged on CQDs have been used as active sensing components in this work. The Porp-CQDs effectively sensed the Zn2+ metal ions with a limit detection of 75 μM in bore well water analysis.

Effect of pH in the bismuth vanadate nanorods for their supercapacitor applications

Abstract The different pH-varied bismuth vanadate nanorods have been synthesized through a solvothermal method and utilized for XRD, HRTEM, SEM and electrochemical studies. The XRD spectra of BV-5 and BV-7 samples show the monoclinic structure. Both electrodes show rod-like morphology. Also, when the pH 7 the bismuth oxide shows large size nanorods compared with pH 5. The interspacing distance of the samples were reduced while the pH was increased. The electrochemical performance of the prepared BV-5 and BV-7 shows higher capacitance values of 235 and 167 F/g for BV-5 and BV-7 electrodes, also these electrodes show a maximum energy density value of 13.4 and 18.8 Wh/kg and related power density values are 720 and 867 W/kg, respectively. The power density value of the BV-7 electrode was increased without affecting the energy density value. Moreover, the cyclic retention of BV-7 shows 93 % at the 1000th cycle. Also, the capacitance and Rct values of BV-7 electrode are comparatively higher than pure BV-5 electrode.

Synergistic integration of ZrO2-enriched reduced graphene oxide-based nanostructures for advanced photodegradation of tetracycline hydrochloride.

The escalating demand for the antibiotic drug tetracycline hydrochloride (TCH) contributes to an increased release of its residues into land and water bodies, which poses risks to both aquatic life and human health. Therefore, it is precedence to effectively degrade TCH residues to protect environment from their long-term impacts. In this aspect, the present study entails the synthesis of zirconia (ZrO2) nanostructures and focuses on the enhancement in the catalytic performance of ZrO2 nanostructures by employing reduced graphene oxide (RGO) as a solid support to synthesize ZrO2-enriched RGO-based photocatalysts (ZrO2-RGO) for the degradation of TCH. The study delves into comprehensive spectroscopic and microscopic investigations and their photodegradation assessments. Powder XRD and HR-TEM studies depicted the phase crystallinity and also displayed uniform distribution of ZrO2 nanostructures with spherical morphology within ZrO2-RGO. This corresponds to high surface-to-volume ratios, providing a substantial number of active sites for light absorption and generation of e--h+ pairs. Moreover, the heterojunctions created between RGO and ZrO2 nanostructures promoted the interspecies electron transfer which prolonged the recombination time of e- and h+ than pure ZrO2 nanostructures, accounted for enhanced degradation of TCH using ZrO2-RGO. The photocatalytic activity of as-synthesized materials were examined under visible and UV light irradiation.Thedegradation efficiency of ~ 73.82% was achieved using ZrO2-RGO-based photocatalystwith rate constant k = 0.007023 min-1 under visible-light illumination.Moreover, under UV-light, the degradation rate was explicated to be k = 0.01017 min-1 with ~ 85.56% degradation of TCH antibiotics within 180 mins. Hence, the synthesized ZrO2-enriched RGO-based photocatalysts represents a promising potential for the effective degradation of pharmaceutical compounds, particularly TCH under visible and UV-light irradiation.

Evolution of Ce4+ Lewis acidity during dehydroxylation of ceria nanoparticles with different morphology: An integrated FTIR, DFT and HRTEM study

Ceria is an important redox catalyst and its activity depends on the open Ce4+/Ce3+ sites, anion vacancies, surface OH groups and the ratio between them. We investigated the effect of dehydroxylation on the evolution of Ce4+ Lewis acidity of oxidized ceria nanocubes, nanopolyhedra, and nanorods. The {111} face is not hydroxylated and the exposed Ce4+ sites, after dehydration, adsorb CO weakly, forming linear carbonyls. The hydroxyl coverage of the {110} face consists of terminal and bridging hydroxyls, and dehydroxylation occurs between 423 and to 573 K by interaction between these groups. The produced Ce4+ sites form stronger linear carbonyls. The {100} face is covered by bridging OH groups, which are progressively removed even at 773 K. The created Ce4+ sites coordinate CO in a bridging mode and, at higher coverage, connect two bridging CO molecules. Ce4+ sites on edges and defects appear at high evacuation temperature and form mono- and dicarbonyls.