Materials Science for Energy Technologies最新文献

A novel organometallic complex adsorbent was synthesized owing to a co-precipitation reaction of iron extracted from pyrrhotite ash residues of the mining activities, catechin extract from green tea, and propylene glycol. Hereafter, the adsorbent (catechin-PG-Fe) was characterized by X-ray diffraction, FTIR, SEM, PZC, and N2 adsorption–desorption. Catechin-PG-Fe shows spherical-like iron oxide nanoparticles of 80 nm dispersed on an amorphous surface, while the specific area was revealed to be significant (230.82 m²/g). Catechin-PG-Fe was then tested for adsorption of Reactive Yellow 145 Azo Dye. The uptake capacity was optimized by the central complex design and response surface methodology, where four adsorption parameters have been considered, including pH (1–5), adsorbent dose (0.6–1.4 g/L), dye concentration (20–260 mg/L) and time (50–250 min). Hence, the adsorbent shows an important capacity for Reactive Yellow 145 of 345.41 mg g⁻¹ at optimum conditions of pH = 1, adsorbent dose = 0.6 g/L, dye concentration = 260 mg/L, and a contact time of 200 min. The experimental data are best fitted to the second-order model, while the equilibrium data fit well to the Freundlich model, which reflects multilayer adsorption on the heterogeneous surface. A comparison within intraparticle and Boyd’s diffusion models confirmed that film diffusion is the rate-limiting step.

Magnesium diboride (MgB₂) is proposed to be a highly efficient wire with zero resistivity. In this research, Mg powder and amorphous-boron sheathed with a stainless steel (SS) 316L tube and powder-in-tube (PIT) technique were used in order to create a cheaper and potential superconductor that could eventually replace the currently expensive price crystalline boron. Mixed powder was put into SS 316L tube and compacted to avoid oxidation while being sintered at a temperature of 800 °C for one hour, prior to cold rolling with various size reduction. X-ray diffraction (XRD), scanning electron microscopy (SEM), and cryogenic magnet characterization were used to evaluate the crystal structures, surface morphology, and resistivity versus temperature and SQUID measurement for all samples. The XRD analysis revealed that the majority of the MgB₂ phase was produced accompanied with a small quantity of MgO and Fe phases. The results of the SEM showed particle agglomeration in the sample’s morphology. It has been found that using the size reduction up to 60 % in the cold rolling step, the critical temperature (Tc) onset of the resulting MgB₂ was calculated to be 39.25 and 39.44 K, respectively. This results reveal that the fabrication of the superconducting wire can be realized using a more economic raw material and process.

In this work, the Wentzel-Kramers-Brillouin (WKB) approximation is used to determine the form factor of a particle having a refractive index close to the outer medium. The analytical expression of the light scattering amplitude by a cylinder with conical ends and a cylinder with ellipsoidal ends in a WKB approximation are calculated for a special case, where the direction of incident light is parallel to the axis of revolution of the particle. For illustration, the numerical results are compared with those computed for the cylinder and ellipsoid.

Bio-based renewable resources have emerged as strong contenders to produce fuels and chemicals via carbon–neutral and eco-friendly methods. In particular, 2,5 furandicarboxylic acid (FDCA) which is listed among the top 12 platform molecules, can be used to produce bio-based polymer as an alternative to polyethylene terephthalate (PET). Notably, FDCA can be produced from an array of biorenewable resources using catalytic materials. However, biomass-derived 5-hydroxymethylfurfural (HMF) remains the primary feedstock to produce FDCA. Thus, the current review focuses on the recent advances in FDCA application and production via catalytic routes, particularly from HMF and other biorenewable feedstocks. Accordingly, the effect of different noble metal and noble metal-free catalytic materials on feedstock conversion and FDCA yield has been discussed. Moreover, the effect of operating conditions such as solvent, bases, oxygen sources, temperature and pressure has been discussed.

The polyaniline-based nanocomposite is a promising candidate for hosting sulfur in cathode materials-based lithium-sulfur batteries. This is because of its strong affinity towards lithium polysulfide and high conductivity. However, with its lower specific surface area and the less polar group, frame structures are unstable, limiting their performance in electrochemical energy storage devices. We have developed PANI – GO – S nanocomposite in ice to grow continuous well-ordered pores structures with high conductivity. The prepared nanocomposite (1 wt%) was mixed with LiNi_0.5Mn_0.5O₂ with polyvinylidene fluoride (PVDF) in N-methyl pyrrolidone (NMP) solvent to make the slurry for the cathode fabrication. The cyclic voltammetry of PANI and its nanocomposite indicates a typical characteristic of the redox peaks at 1.9 V and 2.7 V and the oxidation peak appeared at 2.6 V and 2.2 V that indicates the changing into Li₂S to S²⁻ and later sulfur elemental S₈. The high specific capacity of the LNMO (PANI – GO – S) nanocomposite obtained 868 mAh g⁻¹ up to 400 cycles and above that its value around is around 748 mAh g⁻¹ with the retention rate of 76 % with the same coulomobic efficiency of 98% confirms that the nanocomposite high stability and high corrosion resistance. This outcome of the LNMO (PANI – GO – S) nanocomposite presents a new strategy to fabricate advanced cathodes and high specific capacity of the cathode in a lithium-based electrochemical charge storage cell.

In the present work, polycarbazole (PCz)/magnesium cobalt oxide (MgCo₂O₄)/reduced graphene oxide (RGO) based ternary nanocomposite was prepared through in-situ polymerization, and utilized it as an active electrodes for electrochemical energy storage supercapacitor applications. The electrochemical behaviour of PCz and its nanocomposites were investigated by measuring specific capacitance using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and Galvanostatic charge–discharge (GCD) analysis. The PCz/MgCo₂O₄/RGO hybrids exhibited higher capacitance (548.54 F/g) than that of PCz (117.65 F/g) and PCz/MgCo₂O₄ (482.92 F/g) at the scan rate of 50 mV/s, as determined by CV method. The enhanced supercapacitance indicates high power and energy storage capabilities of the ternary metal oxide-graphene based polycarbazole nanocomposites. Electrochemical impedance spectroscopy confirmed low solution resistance of PCz/MgCo₂O₄/RGO. Thermogravimetric analysis affirmed the increased thermal stability of PCz/MgCo₂O₄/RGO composite compared to that of pure polycarbazole and PCz/MgCo₂O₄ nanocomposite. The scanning electron micrographs of nanocomposite confirmed the successful incorporation of nanofillers into the PCz matrix. On the basis of the research findings, PCz/MgCo₂O₄/RGO can be expected to be a promising electrode active material for high performance energy storage supercapacitors.

To date, many approaches have been made to stabilize the chemical structure of PVC when exposed to sunlight in outdoor usage. This work includes utilizing mefenamic acid (1 % per polymer weight) as a new photo stabilizer unit to adjust PVC to enhance resistance to change under UV exposure. Modification by attaching a new unit that contains an aromatic substance could protect the polymer from UV light due to its ability to absorb it. Positive results were obtained, as the interaction between mefenamic acid and PVC succeeded, using the FTIR technique to characterize the chemical structure of the product. FTIR spectrum of modified PVC shows the disappearance of (OH) band in the region above 3200 cm⁻¹ which is clear evidence that the connection between the polymer and mefenamic acid has happened through the OH group. In addition, we have investigated the influence of microparticle metallic oxides such as TiO₂, and Cr₂O₃, using only 1 % per modified polymer weight, on the photodegradation process of PVC materials. Several approaches have been utilized to investigate the photo-stability of studied materials which are FTIR functional group indices, weight-loss percentage, microscopic images, SEM, and AFM. They demonstrated that modified PVC gives better stability after exposure to UV in comparison to unmodified PVC. It's interesting to note that adding titanium dioxide to modified PVC has increased the amount of UV protection by acting as a UV shielding agent and blocking the light's path to the polymer. Thus, chromium oxide has demonstrated the opposite findings because it functions as a photo-catalytic reagent that accelerated the photo-degradation process. This result may be interpreted as the decomposition of waste PVC, which poses a major threat to the marine ecosystem.