Materials Science for Energy Technologies最新文献

A heat scavenger agent magnesiothermic reduction of quartz sand was used to make Si nanoparticles in a way that can be easily scaled up. Its source of SiO₂ is safe for the environment, easy to get, and cheap. It can make silicon nanoparticles that work well as an anode material for Li-ion batteries. It is known that using inert salt NaCl has a better characterization of Si and electrochemical performance than KCl, KBr, and CaCl₂. XRD diffractogram show 2θ are formed at 27.42°, 47.30°, 56.11°, 69.19°, and 76.37°. The surface area shows 9.75 m²/g, and the pore size is 15.35 Å. In the TEM images, it is found that the silicon shape is spherical. The electrical conductivity voltage of 1 V is 2599.33 µS/cm. The cyclic voltammetry curve during the highest oxidation is 0.57 V, and the lowest oxidation peak is 0.16 V. After the first cycle, the Rs is 4.22 Ω, and the Rct formed is 51.19 Ω. The first discharge capacity is 2599.57 mAh/g, corresponding to coulombic efficiencies at 97.12 %.

The enhancement of photocatalytic reactivity through the internal electric field has received much attention. The combination of the piezoelectric effect and the photo-exiting process facilitates the segregation of the photogenerated carriers, thereby boosting the piezo-photocatalytic activity. We have constructed g-C₃N₄/Ag/ZnO tri-component composites; with various g-C₃N₄ precursors to achieve reliable photo/piezo-photocatalysis for H₂ production and Rhodamine B (RhB) dye degradation. We observed that urea-based g-C₃N₄/Ag/ZnO (UCAZ) tri-components exhibit a superior H₂ production rate of 1125.5 μmol h⁻¹ g⁻¹ under photocatalytic conditions. When piezoelectric-potential was introduced into the photocatalysis reaction via ultrasonic, the H₂ rate increased dramatically to 1637.5 μmol h⁻¹ g⁻¹, which is approximately 145% greater than that light irradiation alone.

Similarly, the catalytic decomposition ratio of Rhodamine B (RhB) under the coexistence of ultrasound and light, and degradation efficiency reached 99% in 120 min, which is higher than the value of (42%, 0.0031 min⁻¹) for piezo-catalysis and (80%, 0.01 min⁻¹) for photocatalysis condition alone. The rate constant under synergistic simulation reaches 0.021 min⁻¹, which is 200% and 645% times higher than the sole light and ultrasonic illumination. Additionally, RhB degradation of all the tri-components was performed under solar light (Sunlight) and ultrasound irradiation, and efficiency reached 99.5% in 45 min with a rate constant of 0.06 min⁻¹, which is 300% higher than the piezo-photocatalytic under LED source. The enhanced performance of the g-C₃N₄/Ag/ZnO tricomponent is attributed to the high specific surface area (168 m² g⁻¹) and synergetic effect of piezo catalysis and photocatalysis.

In the present study, a binary biofuel blend was prepared by blending soy methyl ester (SME100) and methyl oleate (MO) SME50-M50 with diesel. The physiochemical properties of blended fuels were also investigated. The performance and emissions characteristics of all fuel blends were estimated using a common-rail direct injection (CRDI) engine. The outcomes demonstrate a reduction in brake-specific fuel consumption (BSFC) when enriched biodiesel is used in comparison to SME100, nonetheless by the virtue of viscosity and heating value there is an increase in the BSFC value when compared to diesel. The average BSFC values were obtained as 5.3% (E25), 10.6% (E50), 17.5% (E75), 30% (SME100) and 14.9% (SME50-M50) higher than that of diesel. BTE was found to be highest for E25 and lowest for SME100 among all the blends. NOx emissions with blended biodiesel were slightly higher than diesel on account of MO being unsaturated, resulting in shorter ignition delay. The average NOx values obtained were higher than that of diesel and the corresponding values are 2.91% (E25), 4.1% (E50), 5.8% (E75), 8.3% (SME100) and 15.8% (SME50-M50). As a result of the increased oxygen content of the fuel, the concentrations of UHC and CO depreciated with the rise in concentration of soy methyl ester and MO (SME50-M50). Currently, Euro 6.2, which is the most recent emission regulation, uses 10% biofuel (B10); however, the results of this study establishes that E25, as an alternate fuel, complies with the contemporary engines without requiring any engine modifications.

Nanoindentation technique is generally used for measuring thinfilm mechanical properties such as hardness, modulus and stiffness. Nanoindentation of ceramic thinfilms of SiO_2, Si₃N₄ and Al₂O₃ was deposited by radio-frequency (RF) magnetron sputtering on the stainless steel (SS304) substrates using a nanoindenter. Under varied sputtering conditions, the “as-deposited” film was amorphous. The as-deposited thin film had a thickness of 200 nm. The amorphous film was loaded/unloaded only once while operating in load control mode. Hardness and Young's modulus, two mechanical properties of the ceramic thinfilms, were also measured. When SiO₂, Si₃N₄, and Al₂O₃ thinfilms are deposited onto stainless steel substrates using an RF magnetron sputtering, the roughness of the ceramic thinfilms is in the range of 8 to 12 nm. The nanoindentation results were compared, the hardness of the coatings is in the range of 6 to 9 GPa, and these ceramic coatings can be used as an adhesive layer for multilayer thin film coating.

Today, the world’s power system is in transition towards “green” generation in line with the Paris climate agreement of 2015. Emergence of this technology alters existing consumption pattern for mineral resources. Today, center stage is taken by such crucial elements as copper, nickel, lithium, cobalt and, of course, REMs. Permanent REM magnets are pivotal to transition to green and renewable energy. Therefore, in new circumstances the global power system needs different approaches to production and supply chains for key natural resources. Russia’s FEC is the world’s second largest (after the USA) producer of power resources and third largest in-country consumer of the same (trailing the USA and China). However, there is no full-cycle production of individual REMs and REM-based alloys inside the country, despite one of the largest mineral resource bases of REMs in the world. A clearly apparent global trend shows that the pace of developing new MR sources and the necessary investments do not match acceleration in production of such high tech products as solar batteries, wind power generators (WPG), and electric cars. This is due to the fact that many key MRs (especially REMs) come from a small number of producers located in just a few countries. With this in mind, the paper presents a study of the production chain of NdFeB magnets and electric engines based on them, seen as essential to development of Russia’s wind power. Also, economic feasibility of some generation technologies in connection with the ever-increasing power of generators is considered. Basic topologies of electric machines are analyzed as well. The key question of the study is whether rare earth MRs become an incentive for transition to a new energy system in Russia or a bottleneck in the process.

Energy storing devices plays a major role in the development of technology. We synthesized carbon-based nanocomposites through a physical method and CuCo₂O₄ nanocomposites through a sol–gel technique calcined at 600 °C. From X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) confirmed the formation of CuCo₂O₄ nanocomposites which also shows some impurity phase of CuO nanoparticle. The average crystalline size found to be 45 nm. According to optical absorption analysis, the particles show maximum absorption in 256 nm and 369 nm in the UV region, while copper cobaltite doped with activated carbon (AC) shows broad absorption compared with copper cobaltite alone. Morphology studies shows agglomerate image in AC composites and hexagonal structures was formed in CuCo₂O₄ nanoparticles with average particle size of 100 nm. Atomic and weight percentages were recorded using energy dispersive X-ray analysis (EDAX). A good specific capacitance can be found from CV analysis, using electrochemical impedance spectroscopy (EIS), nanoparticles are shown to have different interface properties at the surface of electrodes. Using CuCo₂O₄ and its composite as positive and negative electrodes in cyclic voltammetry (CV) studies shows excellent electrochemical properties. In addition, CuCo₂O₄ with activated carbon is promising as a low-cost and good supercapacitor material.

Using first-principles calculations, in this piece of work, authors have investigated the physical properties of Ra₂LaNbO₆ double perovskite by employing the linearized augmented plane wave (LAPW) method. Structural and electronic properties are determined by using LDA, GGA (WC and PBE), LDA + mBJ, and GGA + mBJ potentials. We have found that Ra₂LaNbO₆ is an indirect band gap (E_g = 2.4 eV) semiconductor. Its elastic and thermodynamic parameters demonstrate its stability. Its optical study indicates that this material opens the door to its applications in optical devices such as photodetectors, solar cells, superlenses, optical fibers, filters, electromagnetic shielding devices, photovoltaic devices, etc. This material is very good for its practical implementation in thermoelectric devices as both p- and n-type material and extends the interest of experimentalists for further investigations. Thus, Ra₂LaNbO₆ is found thermodynamically stable and identified as a potential candidate for photovoltaic and thermoelectric devices.

Modern engineering applications continually strive to develop greater performance mechanical components with good microstructural stability, improved mechanical properties, corrosion resistance and decreased cost of repairing and maintenance. This necessitates the broad use of advanced high performance materials like high entropy alloys (HEAs). These alloys are created by combining five or more alloying elements in equal or substantial amount. About 5 to 35 at. % of the alloying element is present in HEAs. It is characterized primarily by greater entropy, slow diffusion, severe lattice distortion, and cocktail effects. Due to its advanced microstructural stability throughout a larger temperature span and for longer length of time, it demonstrates improved mechanical characteristics at ambient temperature, cryogenic temperature, and elevated temperature. The diversity of elemental contents and significantly higher mixing entropy of HEAs make them mechanically superior to classic metals and alloys. It also shows better strength to weight ratio. Hence, it qualifies as a possible structural and functional material for aeroengine applications. In this work, the studies on the HEAs are briefly reviewed. A basic explanation of the four core effects of HEAs is given. Discussion is held on microstructure and mechanical properties of HEAs. The processing routes for manufacturing of HEAs (arc melting, bridgman solidification, mechanical alloying and vapour deposition) are presented briefly. The influence of heat treatment on mechanical behavior and microstructure of HEAs is presented. The simulation approach of CALPHAD modeling for designing of HEAs is discussed briefly. The future scope for research and development of HEAs in aeroengine applications is briefed.

Nano-silicon is synthesized by hydrothermal method from rice husk, which has the advantage of using low temperature in an autoclave at 180 °C. Reduction of silica using a mixture of silica gel extracted from rice husks with Mg powder. The silica gel and Mg powder reaction produces nano-silicon. XRD diffractogram, it can be seen that Si-0.5, Si-0.6, and Si-0.7 form hkl (1 1 1), (2 2 0), (3 1 1), (4 0 0), (3 3 1), and (4 2 2). Raman spectra show peaks at the Raman shift of 520 cm⁻¹, XPS spectrum high scan Si2p peaks at 99 eV, indicating silicon, and at 103 eV, the oxide layer on nano-silicon. The isotherm adsorption graph using the BET method type IV isotherm graphs with surface areas are 18.60 m²g⁻¹ until 20.39 m²g⁻¹. Pore size using the BJH method shows 1.69 nm until 8.30 nm. SEM and TEM nano-silicon morphology images, the shape of the nano-silicon is spherical. The nano-silicon formed produces high-performance anode lithium-ion batteries with a discharge capacity of 1757 mAh g⁻¹, above 1000 mAh g⁻¹ for approximately 200 cycles.