Facile synthesis of iron-titanate nanocomposite as a sustainable material for selective amination of substitued nitro-arenes

The fabrication of durable and low-cost nanostructured materials remains important in chemical, biologic and medicinal applications. Particularly, iron-based nanomaterials are of central importance due to the ‘noble’ features of iron such as its high abundance, low cost and non-toxicity. Herein we report a simple sol–gel method for the synthesis of novel iron–titanium nanocomposite-based material (Fe9TiO15@TiO2). In order to prepare this material, we made a polymeric gel using ferrocene, titanium isopropoxide and THF precursors. The calcination of this gel in air at 500◦C produced Fe-Ti bimetallic nanoparticles-based composite and nano-TiO2 as support. Noteworthy, our methodology provides an excellent control over composition, size and shape of the resulting nanoparticles. The resulted Fe-based material provides a sustainable catalyst for selective synthesis of anilines, which are key intermediates for the synthesis of several chemicals, dyes and materials, via reduction of structurally diverse and functionalized nitroarenes. © 2020 by the authors. Licensee MDPI, Basel, Switzerland

Monodisperse nickel-nanoparticles for stereo- and chemoselective hydrogenation of alkynes to alkenes

Here, we report the use of monosaccharides for the preparation of novel nickel nanoparticles (NP), which constitute selective hydrogenation catalysts. For example, immobilization of fructose and Ni(OAc)2 on silica and subsequent pyrolysis under inert atmosphere produced graphitic shells encapsulated Ni-NP with uniform size and distribution. Interestingly, fructose acts as structure controlling compound to generate specific graphitic layers and the formation of monodisperse NP. The resulting stable and reusable catalysts allow for stereo- and chemoselective semihydrogenation of functionalized and structurally diverse alkynes in high yields and selectivity. © 2019 The Author(s

Optical scattering from graphene foam for oil imaging/sensing

This work studied a new way of sensing oil leaks using graphene foam through an optical imaging and light scattering method.</p

Impedance Spectroscopy Analysis of PbSe Nanostructures Deposited by Aerosol Assisted Chemical Vapor Deposition Approach

From MDPI via Jisc Publications RouterHistory: accepted 2021-08-21, pub-electronic 2021-10-23Publication status: PublishedFunder: Higher Education Commision, Pakistan; Grant(s): 7363This research endeavor aimed to synthesize the lead (II) diphenyldiselenophosphinate complex and its use to obtain lead selenide nanostructured depositions and further the impedance spectroscopic analysis of these obtained PbSe nanostructures, to determine their roles in the electronics industry. The aerosol-assisted chemical vapor deposition technique was used to provide lead selenide deposition by decomposition of the complex at different temperatures using the glass substrates. The obtained films were revealed to be a pure cubic phase PbSe, as confirmed by X-ray diffraction analysis. SEM and TEM micrographs demonstrated three-dimensionally grown interlocked or aggregated nanocubes of the obtained PbSe. Characteristic dielectric measurements and the impedance spectroscopy analysis at room temperature were executed to evaluate PbSe properties over the frequency range of 100 Hz–5 MHz. The dielectric constant and dielectric loss gave similar trends, along with altering frequency, which was well explained by the Koops theory and Maxwell–Wagner theory. The effective short-range translational carrier hopping gave rise to an overdue remarkable increase in ac conductivity (σac) on the frequency increase. Fitting of a complex impedance plot was carried out with an equivalent circuit model (Rg Cg) (Rgb Qgb Cgb), which proved that grains, as well as grain boundaries, are responsible for the relaxation processes. The asymmetric depressed semicircle with the center lower to the impedance real axis provided a clear explanation of non-Debye dielectric behavior

Facile Synthesis of Iron-Titanate Nanocomposite as a Sustainable Material for Selective Amination of Substitued Nitro-Arenes

The fabrication of durable and low-cost nanostructured materials remains important in chemical, biologic and medicinal applications. Particularly, iron-based nanomaterials are of central importance due to the &lsquo;noble&rsquo; features of iron such as its high abundance, low cost and non-toxicity. Herein we report a simple sol&ndash;gel method for the synthesis of novel iron&ndash;titanium nanocomposite-based material (Fe9TiO15@TiO2). In order to prepare this material, we made a polymeric gel using ferrocene, titanium isopropoxide and THF precursors. The calcination of this gel in air at 500 &deg;C produced Fe-Ti bimetallic nanoparticles-based composite and nano-TiO2 as support. Noteworthy, our methodology provides an excellent control over composition, size and shape of the resulting nanoparticles. The resulted Fe-based material provides a sustainable catalyst for selective synthesis of anilines, which are key intermediates for the synthesis of several chemicals, dyes and materials, via reduction of structurally diverse and functionalized nitroarenes

A facile two-step hydrothermal preparation of 2D/2D heterostructure of Bi2WO6/WS2 for the efficient photodegradation of methylene blue under sunlight

A facile two-step hydrothermal method was successfully used to prepare a photocatalyst Bi2WO6/WS2 heterojunction for methyl blue (MB) photodegradation. Fabricated photocatalysts were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), energy-dispersive X-ray analysis (EDX), and X-ray photoelectron spectroscopy (XPS). Band gap measurements were carried out by diffuse reflectance spectroscopy (DRS). Results indicated that the prepared heterostructure photocatalyst has increased visible light absorption. Photocatalytic performance was evaluated under sunlight irradiation for methylene blue (MB) degradation as a model dye. Variations in pH (4–10), amount of catalyst (0.025–0.1 g/L), and initial MB concentrations (5–20 ppm) were carried out, whereas all prepared catalysts were used to conduct the tests with a visible spectrophotometer. Degradation activity improved with the pH increase; the optimum pH was approximately 8. Catalyst concentration is directly related to degradation efficiency and reached 93.56% with 0.075 g of the catalyst. Among tested catalysts, 0.01 Bi2WO6/WS2 has exhibited the highest activity and a degradation efficiency of 99.0% in 40 min (min) for MB. MB photodegradation follows pseudo-first-order kinetics, and obtained values of kapp were 0.0482 min−1, 0.0337 min−1, 0.0205 min−1, and 0.0087 min−1 for initial concentrations of 5 ppm, 10 ppm, 15 ppm, and 20 ppm, respectively. The catalyst was reused for six cycles with a negligible decrease in the degradation activity. Heterostructure 0.01 Bi2WO6/WS2 has exhibited a photocurrent density of 16 μA cm−2, significantly higher than 2.0 and 4.5 μA cm−2 for the pristine WS2 and Bi2WO6, respectively. The findings from these investigations may serve as a crucial stepping stone towards the remediation of polluted water facilitated by implementing such highly efficient photocatalysts.</p

Transport and accumulation of ferrocene tagged poly(vinyl chloride) at the buried interfaces of plasticized membrane electrodes

Cyclic voltammetry (CV), synchrotron radiation-X-ray photoelectron spectroscopy (SR-XPS) and near edge X-ray absorption fine structure (NEXAFS) show that oxidation of ferrocene tagged PVC induces an accumulation of high molecular weight polymer at the buried interface between the substrate electrode and the plasticized membrane

Enhanced Electrocatalytic Activity of Amorphized LaCoO3 for Oxygen Evolution Reaction

Amorphous inorganic perovskites have attracted significant attention as efficient electrocatalysts due to their unique structural flexibility and good catalytic activity. In particular, the disordered structure and a surface rich in defects such as oxygen vacancies can contribute to the superior electrocatalytic activity of amorphous oxides compared to their crystalline counterpart. In this work, we report the synthesis of LaCoO3, followed by an amorphization process through urea reduction with tailored modifications. The as-synthesized catalysts were thoroughly tested for their performance in oxygen evolution reaction (OER), Remarkably, the amorphous LaCoO3 synthesized at 450 °C (referred to as LCO-4) exhibits excellent OER catalytic activity. At an overpotential of 310 mV, it achieved a current density of 10 mA/cm−2, exceedingly fast to 1 A/cm−2 at an overpotential of only 460 mV. Moreover, LCO-4 exhibited several advantageous features compared to pristine LaCoO3 and LaCoO3 amorphized at other two temperatures (350 °C, LCO-3, and 550 °C, LCO-5). The amorphized LCO-4 catalyst showed a higher electrochemically active surface area, a key factor in boosting catalytic performance. Additionally, LCO-4 demonstrated the lowest Tafel slope of 70 mVdec−1, further highlighting its exceptional OER activity. Furthermore, the long-term stability of LCO-4 is notably superior than pristine LaCoO3 (LCO-P) and the other amorphized samples (LCO-3 and LCO-5). The enhanced catalytic activity of LCO-4 can be attributed to its unique disordered structure, small crystallite size, and higher concentration of oxygen vacancies in the final catalyst.</p