Room Temperature Stirring Research Articles

Superior supercapacitor performance with tuneable 2D/3D morphological microporous carbons of zeolitic imidazolate frameworks synthesized by recycling mother liquors

Carbonized metal–organic frameworks (MOFs)-based nanoporous carbon materials (NPCs) offer attractive activities in electrochemical energy conversion and storage (EECS) applications; however, there is the need for scalable MOFs production under reduced energy/environmental impact. This study reports a green synthesis route for model zeolitic imidazolate framework (ZIF-8) materials via recycling methanol-based mother liquors (ZIF-RMLx) under room temperature stirring and their carbonized materials (CZC-RMLx) for high-performance supercapacitors. Series of ZIF-RMLx samples produced in four recycles offer rod-/sheet-/polyhedral-like 2D/3D microstructures with tuneable internal and external framework and morphological features. Accordingly, CZC-RMLx, obtained by direct pyrolysis, with high microporosity and surface area of 1500 m2 g−1 deliver excellent capacitance values of 200–340 F g−1, compared to typical MOFs-derived or chemically activated/templated NPCs, produced via extended chemical processing. Structure-relevant and comparative performance analysis reveal insights for improved charge storage and carbonization-dependent graphitization, nitrogen-doping and microporosity-controlled capacitance characteristics in the CZC-RMLx over typical NPCs in literature. The device-level performance with a long-term durability over 21,000 cycles is demonstrated. The practical potential of CZC-RMLx is further evaluated by fabricating solid-state cells and their parallel and series circuit combinations result in overall capacitance and voltage boost to 450 F g−1 and 2.4 V, respectively.

Highly Efficient Non-Enzymatic Electrochemical Glucose Biosensor Based on Copper Metal Organic Framework Coated on Graphite Sheet

Detection of glucose is highly informative, creating a constant demand for fabricating high-precision glucose biosensors. Metal–organic frameworks, a family of porous materials renowned for their tunability, can be an excellent choice for developing such sensors. We have developed a highly-sensitive, non-enzymatic sensor for electrochemical detection of glucose fabricated using Copper Metal–Organic Framework (Cu MOF), synthesized by a simple, room-temperature stirring method using Benzene-1,3,5-tricarboxylic acid (BTC) as ligand and Copper nitrate trihydrate as precursor. The synthesized nanostructure was characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, and energy-dispersive X-ray analytical techniques. Powder X-ray diffraction study and thermogravimetric analysis were also done. Further, Brunnauer-Emmett-Teller analysis revealed the porous nature of Cu MOF. The materials exhibited strong electro-catalytic activity for glucose oxidation as revealed from cyclic voltammetry and chronoamperometric studies done under alkaline pH conditions. The Cu MOF deposited on a conducting graphite sheet electrode displayed a significantly low detection limit of 0.019 mM through a broad detection range (1–15 mM) and a strong sensitivity of 229.4 μAmM−1 cm2. Overall, the Cu MOF/GS exhibits exceptional stability, short response time (less than 1 s), and good repeatability and reproducibility, making it a promising future material for non-enzymatic glucose detection.

Rapid, Massive, and Green Synthesis of Polyoxometalate-Based Metal-Organic Frameworks to Fabricate POMOF/PAN Nanofiber Membranes for Selective Filtration of Cationic Dyes.

Developing high-efficiency membrane materials for the rapid removal of organic dyes is crucial but remains a challenge. Polyoxometalates (POMs) clusters with anionic structures are promising candidates for the removal of cationic dyes via electrostatic interactions. However, their shortcomings, such as their solubility and inability to be mass-produced, hinder their application in water pollution treatment. Here, we propose a simple and green strategy utilizing the room temperature stirring method to mass produce nanoscale polyoxometalate-based metal-organic frameworks (POMOFs) with porous rhomboid-shaped dodecahedral and hexagonal prism structures. The products were labeled as POMOF1 (POMOF-PW12) and POMOF2 (POMOF-PMo12). Subsequently, a series of x wt% POMOF1/PAN (x = 0, 3, 5, and 10) nanofiber membranes (NFMs) were prepared using electrospinning technology, where polyacrylonitrile (PAN) acts as a "glue" molecule facilitating the bonding of POMOF1 nanoparticles. The as-prepared samples were comprehensively characterized and exhibited obvious water stability, as well as rapid selective adsorption filtration performance towards cationic dyes. The 5 wt% POMOF1/PAN NFM possessed the highest removal efficiency of 96.7% for RhB, 95.8% for MB, and 86.4% for CV dyes, which realized the selective separation over 95% of positively charged dyes from the mixed solution. The adsorption mechanism was explained using FT-IR, SEM, Zeta potential, and adsorption kinetics model, which proved that separation was determined via electrostatic interaction, hydrogen bonding, and π-π interactions. Moreover, the POMOF1/PAN membrane presented an outstanding recoverable and stable removal rate after four cycles. This study provides a new direction for the systematic design and manufacture of membrane separation materials with outstanding properties for contaminant removal.

Unraveling hierarchical hollow NiCo2S4/MXene/N-doped carbon microspheres via dual templates for high-performance hybrid supercapacitors

A multi-step strategy was rationally designed to fabricate hierarchical hollow core–shell microspheres of NiCo2S4MXene/N-doped carbon (NiCo2S4/MXene/NC) using dual templates of the polyethylene microspheres and metal–organic framework material of ZIF-67. The integration of MXene and N-doped carbon significantly enhances the electronic conductivity of electrode, while the construction of hollow spherical structures effectively alleviates the instability of NiCo2S4/NC during the charge–discharge cycles, leading to the excellent charge storage performance with a high specific capacitance (1786 F g−1 at 1 A g–1) and impressive cycling stability (over 100 % capacitance retention after 10,000 cycles). A corresponding hybrid supercapacitor displays a high specific capacitance (190 F g−1 at 1 A g–1) with a maximum energy density (67 Wh kg−1 at 796 W kg−1) and great cycling stability (over 80 % capacitance retention after 10,000 cycles). The charge storage mechanism of NiCo2S4/MXene/NC is elucidated, revealing a combination of pseudocapacitive and battery-like behavior. Density functional theory (DFT) calculations indicate that the participation of MXene significantly increases the state density of NiCo2S4/MXene near the Fermi level compared to NiCo2S4, affirming its superior metallic conductivity. This work provides a facile route only with room-temperature stirring and high-temperature calcination to prepare well-defined metal sulfide composite microstructures with high electrochemical performance.

Green Method Synthesis of Magnetic Nanoparticles and its Functionalized MNPs for Knoevenagel Condensation Reaction

Background: Knoevenagel condensation is an important C-C bond formation reaction catalyzed by various homogeneous and heterogeneous acid-base catalysts. background: Knoevenagel condensation is an important C-C bond formation reaction, and employs various acid and base-catalyzed reactions of both homogeneous and heterogeneous catalysts. Method: The present work describes the eco-friendly preparation of magnetic nanoparticles Fe3O4 (MNPs) and its functionalization to Fe3O4@SiO2@SO3H. The prepared MNPs and their functionalized materials were fully characterized by FT-IR, XRD, FE-SEM, HR-TEM, and VSM. Further demonstrated application of these catalysts for the C-C bond formation reactions of Knoevenagel condensation employing special aldehyde derivatives with malononitrile at room temperature gave excellent product isolation. Results: The application of the prepared functionalized MNPs for the Knoevenagel condensation was demonstrated by the reaction of various aryl/heterocyclic and cholesterol aldehyde with malononitrile at room temperature stirring for about 30 min in ethanol solvent. The final product isolated is confirmed by various spectroscopic techniques such as FT-IR, 1H-, & 13C-NMR, and mass spectrometry. Furthermore, the selected compounds are screened for their photophysical properties, and interestingly compound 3j showed good fluorescent properties. Conclusion: Overall the present work described a greener method preparation of MNPs, and its functionalized employed as a heterogeneous catalyst for the Knoevenagel condensation of various aryl/heterocyclic and cholesterol aldehyde with malononitrile. The method developed is simple, easily separated catalyst by an external magnet, and recycled up to five cycles without any noticeable change in the final product isolation. Further, the prepared derivatives screened for their photophysical properties, and interestingly compound 3j showed good fluorescent properties.

Self‐Assembled 3D N/P/S‐Tridoped Carbon Nanoflower with Highly Branched Carbon Nanotubes as Efficient Bifunctional Oxygen Electrocatalyst Toward High‐Performance Rechargeable Zn‐Air Batteries

AbstractHeteroatom doping and 3D nanostructures with large specific surface area and hierarchical porous structure can synergically improve oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). In this study, the 3D N/P/S‐tridoped nanoflower with highly branched carbon nanotubes bifunctional catalyst (Co/SP‐NC) is prepared by a simple self‐assembly pyrolysis method. The powerful driving force of coordination interaction of ammonium ion can promote the self‐assembly of 2D ZnCo‐ZIF nanosheets into 3D ZnCo/S‐ZIF nanoflowers at room temperature stirring. The 3D ZnCo/S‐ZIF nanoflower surface is driven by sodium hypophosphite to form highly branched carbon nanotubes during the pyrolysis process. Moreover, Density functional theory (DFT) calculations also confirm that the simultaneous introduction of N/P/S can promote the redistribution of electron density at the catalyst interface. The proper P‐doping not only enhances the electronic conductivity of the substrate, but also facilitates the charge transfer in the OER/ORR process. Therefore, Co/SP‐NC cathode assembled zinc‐air batteries (ZABs) have a higher power density (187 mW cm−2), a larger specific capacity (801 mAh gZn−1) and excellent cycle stability compared to Pt/C‐RuO2 assembled ZABs. This work will pave the way to regulate the components interactions by designing 3D hierarchical porous structures.

Engineering of metal Co/Ni-CoO nanoparticles embedded in N-doped unclosed hollow carbon nanoboxes as a highly efficient bifunctional electrocatalyst for overall water splitting

Hollow materials are attracting considerable attention in water electrolysis due to their clear internal space and large surface areas. However, the completely enclosed hollow nanostructures are affected by the large mass-transfer resistance and incompletely exposure of the inner space. Here, an unclosed hollow electrocatalyst consisting of metal Co-loaded Ni-doped CoO multiphase nanoparticles inserted in N-doped hollow carbon shells (Co/Ni-CoO@NC) is designed and constructed by a room-temperature stirring corrosion method and subsequent pyrolysis. The as-prepared Co/Ni-CoO@NC displays outstanding electrocatalytic activities for both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) in alkaline electrolytes. And the optimized products show an ultra-small overpotential of only 61 mV at 10 mA cm−2 current density for HER. For OER, the overpotential is 215 mV at the same current density. The excellent catalytic properties of Co/Ni-CoO@NC are mainly due to the high electrical conductivity of nitrogen-doped carbon materials (NC), the great specific surface area of the hollow NC nanoboxes, the exposed internal space and accessible active sites, and the abundant mass transfer channels of the hollow architectures. Moreover, the obtained catalysts exhibit excellent durability and stability in HER and OER applications. This research develops a feasible way to construct bifunctional unclosed hollow electrocatalysts for decomposing water.

Synthesis, molecular structure, DFT studies, non-covalent interaction plots, Hirshfeld surface analysis and molecular docking studies of homoleptic Mn(II)(4,4,4-trifluoro-1-phenyl-1,3-butanedione)2

A simple room temperature stirring reaction of MnCl2·4H2O and 4,4,4-trifluoro-1-phenyl-1,3-butanedione (TFPBDH) afforded a yellow crystals of monomeric, square-planar Mn(TFPBD)2 as revealed by single-crystal X-ray diffraction and DFT analysis (B3LYP/6–311+G(d,p)/LanL2DZ). ESI-MS analysis confirms the solution stability of Mn(TFPBD)2 and further supported by FT-IR and UV–Vis analysis. Quantum theory of atoms in molecules (QTAIM) analysis, non-covalent interaction (NCI) plots, Hirshfeld surface (HS) analysis (CE-B3LYP/6–31G(d,p) were carried out to understand the CH···F, CH···π and other intra- and intermolecular interactions prevails within the supramolecular architecture. Further, the molecular stability was assessed in terms of interaction energy (IE) calculations by constructing various energy frameworks through electrostatic, dispersion, polarization, and repulsion energies (total IE = −162.8 kJ mol−1). The in silico molecular docking demonstrates the binding affinity of Mn(TFPBD)2 towards penicillin-binding protein 2, PBP2 (6G9S) and staphylococcal aureus FtsZ (4DXD) with an excellent binding score of −6.36 and −9.84 kcal/mol respectively.

Tunable Non-Enzymatic Glucose Electrochemical Sensing Based on the Ni/Co Bimetallic MOFs.

Constructing high-performance glucose sensors is of great significance for the prevention and diagnosis of diabetes, and the key is to develop new sensitive materials. In this paper, a series of Ni2Co1-L MOFs (L = H2BPDC: 4,4'-biphenyldicarboxylic acid; H2NDC: 2,6-naphthalenedicarboxylic acid; H2BDC: 1,4-benzenedicarboxylic acid) were synthesized by a room temperature stirring method. The effects of metal centers and ligands on the structure, compositions, electrochemical properties of the obtained Ni2Co1-L MOFs were characterized, indicating the successful preparation of layered MOFs with different sizes, stacking degrees, electrochemical active areas, numbers of exposed active sites, and glucose catalytic activity. Among them, Ni2Co1-BDC exhibits a relatively thin and homogeneous plate-like morphology, and the Ni2Co1-BDC modified glassy carbon electrode (Ni2Co1-BDC/GCE) has the highest electrochemical performance. Furthermore, the mechanism of the enhanced glucose oxidation signal was investigated. It was shown that glucose has a higher electron transfer capacity and a larger apparent catalytic rate constant on the Ni2Co1-BDC/GCE surface. Therefore, tunable non-enzymatic glucose electrochemical sensing was carried out by regulating the metal centers and ligands. As a result, a high-sensitivity enzyme-free glucose sensing platform was successfully constructed based on the Ni2Co1-BDC/GCE, which has a wide linear range of 0.5-2899.5 μM, a low detection limit of 0.29 μM (S/N = 3), and a high sensitivity of 3925.3 μA mM-1 cm-2. Much more importantly, it was also successfully applied to the determination of glucose in human serum with satisfactory results, demonstrating its potential for glucose detection in real samples.

Preparation of Pt/ZIF-7 hybrid porous material and its application in hydrogen fuel cell

Hydrogen fuel cell vehicles are the most ideal low-carbon and environmentally friendly new energy vehicles, but the catalyst for hydrogen fuel cells requires the use of precious metal platinum. At present, the catalysts for hydrogen fuel cells mainly rely on imports, greatly limiting the development of hydrogen fuel cell vehicles in China. We used a simple and energy-saving room temperature stirring method to in-situ load polyvinyl pyrrolidone modified Pt onto ZIF-7, so that the surface of ZIF crystal can continuously absorb PVP modified Pt nanoparticles while growing. PVP is a non-ionic surfactant, which can not only stabilize Pt nanoparticles in polar solvents, but also control the size and shape of Pt nanoparticles as a capping agent. This can not only avoid the agglomeration of Pt nanoparticles to keep their original characteristics, but also effectively control the spatial distribution of Pt nanoparticles in ZIF-7. The catalysts Pt/ZIF-7 were prepared, with corresponding Pt content of 0.052%, 0.26%, 0.52%, and 1.04%, respectively. Subsequently, we will apply the prepared Pt/ZIF-7 catalyst to hydrogen fuel cells and test its catalytic performance.

Augmented dye eradication from wastewater using alkali-aided, reinforced waste acacia (Acacia auriculiformis) leaves

The present investigation demonstrates the augmented dye scavenging from wastewater using alkali-mutated acacia (Acacia auriculiformis) leaves powder. The material was synthesized by mild chemical activation by using 0.1 M sodium hydroxide as an activator under room temperature stirring for 3h and isolated as a dark brown powder. The material was characterized using FTIR, FESEM, XRD, and pHzpc; and tested successfully with crystal violet and methylene blue. While FTIR confirms the presence of polyphenolic and polysaccharide moieties, FESEM reveals unprecedented circular hollow pipe-like channels decorated in a highly ordered fashion, facing pores for optimum dye uptake. The adsorption is tunable with working pH, and the maximum adsorption capacities are 67.25 and 78.55 mg g−1 for CV and MB. Both adsorption process follows Langmuir isotherm (R 2 = 0.994) and pseudo-2nd-order kinetics (R 2 = 0.999). Thermodynamic analysis verifies a spontaneous process with an endothermic interaction beside an elevated degree of randomness. About 80% of the spent material could be regenerated using 1:1 methanol/water. Analysis of industrial effluent suggests 37% removal per cycle, with an operating ceiling of 95%. To wind up, due to huge availability, porous nature, and superior adsorption capacity over other phytosorbents, NaOH-activated acacia leaves could be considered as techno-economic and potential scavengers for sustainable water treatment.

Nickel‐doped Co3O4 electrocatalyst derived from bimetal zeolitic imidazolate frameworks for the oxygen evolution reaction of electrolysis

Oxygen evolution reaction (OER), as a multi‐step coupled anode reaction, is more sluggish in kinetics than electrocatalytic hydrogen evolution reaction (HER). In order to overcome the potential barrier in OER, it is necessary to develop high‐efficient non‐noble metal catalysts for energy utilization. In this work, several NiCo‐ZIF materials with different molar ratios of Ni and Co were prepared by doping Ni2+ in the preparation of ZIF‐67 via a simple room temperature stirring method. After that, NiCo‐ZIF was calcined at 350°C in a muffle furnace to obtain corresponding Ni‐doped Co3O4 (Ni‐Co3O4). Ni‐Co3O4 catalyst exhibits a low overpotential (η ≈ 203 mV @10 mA cm−2), a small Tafel slope (111.0 mV dec−1) and prominent stability for OER in 1 M KOH solution, which is higher than for a commercially available Ir/C electrocatalyst (η ≈ 350 mV @10 mA cm−2). The higher electrochemical performance should be largely ascribed to the introduction of oxygen vacancies resulting from the Ni doping, which leads to the improved electrochemical active surface area (122.81 mF cm−2) and the topological structure of the dodecahedron, which is in favor of the good contact area between the catalyst and the electrolyte. The design and synthesis of ZIF‐derived catalyst in this work create a significative method to prepare efficient OER electrocatalysts.

From laboratory to industrialization: Eco‐friendly flame retardant endowing epoxy resin with excellent flame retardancy, transparency, and mechanical properties

AbstractTo eliminate the fire safety hazards (flammability and smoke toxicity) of epoxy resins (EP), while reaching industrial production of flame retardants, we proposed a facile strategy to successfully synthesize an industrially scalable phosphorus‐nitrogen flame retardant (named FNU) by the substitution reaction of 2‐(2‐aminoethylamino) ethanol and 9,10‐dihydro‐9‐oxo‐10‐phosphofi‐10‐oxide. FNU was synthesized in a simple and heat‐free step with room temperature stirring, and such process optimizations facilitate industrially scalable. As expected, FNU endowed EP with excellent flame retardancy and smoke suppression properties. EP mixing with 10 phr of FNU reached the highest limiting oxygen index value of 44.5%, UL‐94 reached V‐0 level, total smoke production and total heat release were reduced by 15.5% and 19.8% compared with pure EP. Residual carbon analysis showed that the presence of FNU could promote to form dense and continuous carbon layer. Thermogravimetric analysis‐infrared spectrometry results demonstrated a significant reduction in the pyrolysis products, especially in the yield of CO. Moreover, the structure of FNU contained aromatic rigid and reactive amine groups that significantly improved the mechanical properties of EP without affecting its transparency, retaining its value for applications in optical materials.

Turn On/off Fluorescence in the Presence of Zn(ii) and Tb(iii) Metal Ions in The Schiff Base Complex

Zinc is one of the most essential trace elements in periodic table which is directly involved in several enzymatic and biological activities in human body. Research has mainly focused in the catalytic and biological applications of Zinc complex; however the fluorescence property and its co-relation with the 3d and 4f metal ions are hitherto unexplored. In the last decades several fluorescence active Schiff base (H2 L) was synthesised using o-vanillin and ethylene diamine in room temperature stirring. Herein, metal complexes of Zn(II) and Zn(II)-Tb(III) were synthesised and characterized. Photo physical properties of all these complexes were studied using fluorescence spectroscopy. Interestingly it has been found that the Zn(II) complex shows enhanced fluorescence intensity than the other complexes. However, the fluorescence intensity of Zn(II)-Tb(III) complex decreases compare to the Zn(II) complex. The chelation enhanced fluorescence plays the major role for the enhanced fluorescence intensity of the Zn(II) complex however the presence of paramagnetic metal centre in Zn(II)-Tb(III) complex decreases the overall fluorescence intensity as compare to the Zn complex.

Effect of synthesis method on the oxygen reduction performance of Co–N–C catalyst

In recent years, Co, N co-doped carbon (Co–N–C) materials as oxygen reduction reaction (ORR) catalysts have attracted great attention because of their good ORR stability as well as decent activity. Co-doped zeolitic imidazolate framework-8 (Co@ZIF-8) as the precursor for synthesizing Co–N–C has attracted great interest recently. Co@ZIF-8 synthesis method may affect the properties of the as-synthesized Co@ZIF-8 precursors, which will surely affect the properties and ORR performance of Co@ZIF-8-derived Co–N–C catalysts. Herein, three methods, viz. room-temperature stirring method, reflux method, and hydrothermal method, were used to synthesize Co@ZIF-8 precursors. Physical characterization shows that the synthesis method has a great influence on the textural properties, composition, and graphitization degree of the as-synthesized Co–N–C catalysts. Electrochemical characterization shows that Co–N–C-R synthesized with reflux method exhibits an onset potential (Eonset) of 0.905 V, a half-wave potential (E1/2) of 0.792 V and a limiting current density (JL) of 5.85 mA cm−2 in acidic media, which are higher than those of Co–N–C–S (Eonset = 0.870 V, E1/2 = 0.770 V, JL = 4.71 mA cm−2) and Co–N–C–H (Eonset = 0.892 V, E1/2 = 0.785 V, JL = 4.68 mA cm−2) synthesized with room-temperature stirring method and hydrothermal method, respectively. The better ORR activity observed on Co–N–C-R can be attributed to its larger graphitization degree and larger mesopore volume. Catalytic stability test shows that Co–N–C-R has negligible activity loss after 5000 potential cycles. This work demonstrates that reflux method is a more suitable method for synthesizing Co–N–C catalysts for ORR.

Enhancement of photocatalytic activity of Z-scheme BiO2-x/BiOI heterojunction through vacancy engineering

Facing water pollution problems, developing a photocatalyst that can remove multiple pollutants with high redox ability is necessary. In this study, novel BiO2-x/BiOI with Z-scheme heterojunction and oxygen vacancies was synthesized by room temperature stirring process. A series of techniques including TEM, Raman, XPS and ESR confirmed BiO2-x/BiOI structure was successfully formed. Photocurrent, EIS impedance indicated the high separation efficiency of photogenerated electrons and holes between two semiconductors. The optimum sample 30% BiO2-x/BiOI can degrade 96.4% rhodamine B (RhB), 88.7% methyl orange (MO) and 74.5% tetracycline (TC) within 90 min, respectively, and can inactivate 100% E. coli and S. aureus in 15 min and 20 min, respectively. These performance was realized under lower energy consumption light source (LED light), smaller amount of catalyst and shorter reaction time compared with related BiOI-based composites. The excellent photocatalytic performance was mainly attributed to the Z-scheme BiO2-x/BiOI heterojunction with oxygen vacancy: (i) Z-scheme between BiO2-x and BiOI can induce a strong redox ability of its photo-induced electrons and holes, (ii) the oxygen vacancies in BiO2-x are conductive to the separation of photoexcited charges. This work offers a new example in improving the performance of composite semiconductor systems to be high and multiple efficiency photocatalyst.

A facile fabrication of a multi-functional and hierarchical Zn-based MOF as an efficient catalyst for CO2 fixation at room-temperature

Multi-functional and hierarchical Zn-MOF was rapidly synthesized by room-temperature stirring using an organic amine as a protonation agent and exhibited remarkable improvement for CO2 cycloaddition to bulky epoxides.

Electrical and Structural properties of (ZnTiO3)/Epoxy System Nanocomposite Thin films

Spin coating technique using to prepare two layers of epoxy reinforced by weight (0Wt%,1Wt%,2Wt%,3Wt%,4Wt%) nano ZnTiO3additives uniform thin films with a fixed thickness of (0.7 ☐m) on glass floors at room temperature, dispersion and magnetic stirring techniques are used to prepare the nanocomposites thin films. The purpose of this study was to produce a new modified polymer (ZnTiO3/Epoxy) nanocomposite thin films then evaluate electrical and structural properties of these thin films. The electrical properties of thin films have a degree effect temperature on the resistance (R) of thin films within the range (303- 433) k or (30-160) C0. Electrical conductivity and activation energy of the thin film was calculated where the results indicate that there is a two activation energy and this means there is two mechanisms connection. It is also shown by measurements of the effect of the whole (ZnTiO3/Epoxy) nanocomposite thin films have a connection from the negative type (n-type). Stractural properties include XR-D and SEM. XRD, show crystal structure of zinc titanite (ZnTiO3) nano powder. Scanning electron microscopy SEM, show clearly analysis for different weight ratio affected thin films surfaces.

Acid catalyzed Knoevenagel condensation of thiobarbituric acid and aldehyde at room temperature

Knoevenagel reactions have been performed by the action of various unsymmetrical thiobarbituric acids containing activated methylene carbon and electron deficient center of aromatic aldehydes using small amount of acetic acid as initiator in ethanolic medium. The present protocol proceeded smoothly on room temperature stirring using ethyl alcohol as solvent with the help of initiator. The work-up procedure is very simple and products have been purified by simple recrystallization. Thus rendering the methodology is good and all synthesized molecules were characterized by 1H, 13C NMR, and MS spectra.

Near room temperature synthesis of rGO-Fe3O4 nanosheets: Structural, magnetic ordering, charge transport, dye degradation properties and hydrogen evolution reaction

Abstract Reduced graphene oxide (rGO)-Fe3O4 nanosheets were synthesized at near room temperature stirring method. X-ray diffraction results showed the formation of Spinel structure of Fe3O4 with a broad diffraction pattern of reduced graphene oxide sheets. Vibrating sample magnetometery was employed to investigate the superparamagnetic behavior of Fe3O4 nanoparticles decorating rGO sheets. The estimated size of superparamagnets obtained 11 nm which was in well in agreement with XRD analysis (14 nm) and FESEM images (13 nm). A new splitting feature in high magnetic files were observed in the hysteresis curve of samples. A dipole-dipole magnetic interaction was employed to estimate the interparticle separation for the first time. The results obtained roughly 3 nm which was in good agreement with the results mean pore diameter from BET-BJH analyses. The effective surface area was obtained 97 m2 g−1 and 20 m2 g−1 for Fe3O4 and rGO-Fe3O4, respectively. Cyclic voltamettery and impedance spectroscopy revealed the significant enhancement of charge transfer for rGO-Fe3O4 hybrid nanosheets. The polarized light off-on measurement obtained a net current of 0.05 mA cm−2 which is comparable to metal chalcogenide nanostructures. Linear sweep voltamettery and corresponding Tafel plot analysis revealed an exchange current density of 210 μA cm−2 and Tafel slope of 100 mV decade−1 for rGO-Fe3O4 optimized sample. Moreover, it showed a superior methylene blue degradation of 98% and pseudo-linear degradation rate constant of 78 × 10−3min−1 which is much higher than the value of 27 × 10−3 min−1 for Fe3O4 nanoparticles. Cyclic photocatalyst activity of rGO-Fe3O4 demonstrates only 3% degradation of its performance after 5 cycles.