Materials Science for Energy Technologies最新文献

Manganese dioxide-multiwall carbon nanotube (MnO₂-MWCNT) nanocomposites were synthesized via one-pot synthesis method with varying concentrations of 1 mg/ml, 4 mg/ml, and 10 mg/ml MWCNT. The synthesized nanocomposites were characterized using x-ray diffraction (XRD), transmission electron microscopy (TEM), and electrochemical measurements. The intent of studying different concentrations is, ultimately, to correlate the effect of the concentration of multiwall carbon nanotube on the electrochemical performance of the MnO₂-MWCNT nanocomposites_. Two primary phenomena were observed as CNT concentration increased. First, less crystalline MnO₂ adsorption onto individual CNTs occurred. Subsequently, CNT agglomeration became the primary feature of the nanostructures of high CNT concentration. The electrochemical studies reveal that the specific capacitance of MnO₂ increases from 124 F/g to 145 F/g by the addition of 1 mg/ml MWCNTs and decreases to 102 F/g for MnO₂-10 mg/ml MWCNT nanocomposite.

The semiconductor oxide material titanium dioxide (TiO₂) has a number of strategic uses, such as an antimicrobial, self-cleaning, photocatalyst, and dye-sensitized solar cell (DSSC). Despite the fact that his substance is naturally obtained from the ilmenite (FeTiO₃) mineral, there have been few investigations in this field. This work produced heterogenous TiO₂ nanocrystals from ilmenite extraction, which were then subjected to post-hydrothermal treatment at a range of temperatures of 80, 100, 120, and 150 °C. In the present study, it was examined how temperature change affected the optical characteristics, crystal structure, and prospective integration of TiO₂ nanocrystals into DSSC. The obtained TiO₂ nanocrystals were identified as anatase phase by the X-ray diffraction analysis. As a result of raising the post-hydrothermal temperature from 80 to 150 °C, the crystallite size of heterogenous TiO₂ nanocrystals was successfully enhanced from 58.09 to 72.48 nm. The band gap energy (E_g) may be lowered from 2.81 to 2.65 eV by increasing the size of the crystallites. The greatest open circuit voltage (V_oc) measured by the voltage test findings was 16.80 mV. According to the study's findings, heterogenous TiO₂ nanocrystals synthesized from the ilmenite mineral might be used in dye-sensitized solar cell applications.

Organic pollutants such as 4-nitrophenol (4-NP) pose serious environmental extortions due to their chemical stability for which efficient catalytic materials are indispensable in treating them. In this regard, the present work involves the synthesis of two different types of ferrites (NiFe₂O₄, and CuFe₂O₄), and a combination of Ni_xCu_xFe₂O₄ with various ratios that systemically work as efficient photocatalysts without any additional reducing agents is reported. The structural, and morphological properties of NiFe₂O₄, CuFe₂O₄, and NiCuFe₂O₄ were characterized by XRD, FT-IR, SEM, and HRTEM techniques. Then, the catalytic role of individual ferrite catalysts was evaluated towards catalytic reduction of 4-NP under visible light. The progress dye reduction was examined via UV–vis spectrophotometry. The effect of various concentrations, and reduction time were investigated. The kinetic rate constants determined for NiFe₂O₄, CuFe₂O₄, and Ni_xCu_xFe₂O₄ revealed that Ni and Cu in bimetallic ferrites promoted the reduction reaction under visible light. The results demonstrated that the photo-reduction efficiency of the Ni_0.7Cu_0.3Fe₂O₄ catalyst over 4-NP (conc. 10 ppm) to 4-AP was determined as 82 % under 120 miniutes with good recyclability up to six cycles. The mechanism of photocatalytic reduction of ferrites without the use of a reducing agent was studied. Such facile and productive ferrite materials could be employed as efficient photocatalysts for the reduction of toxic organic contaminants in environmental treatment.

This study presents a comprehensive investigation on the synthesis and characterization of surfactant-assisted graphene oxide non-covalent functionalized silver nanocomposites (rGS-AgNPs) for achieving remarkable photocatalytic and anti-biofilm properties. The approach involves using an anionic surfactant (sodium lauryl sulfate (SLS)), silver nitrate (AgNO₃), and reduced graphene oxide (rGO) as stabilizing/reducing agents, metal precursors, and supporting materials, respectively. Different composites were prepared by varying the concentration of AgNO₃, resulting in rGS-AgNPs composites with concentrations of 0.9 × 10⁻³ mM, 1.8 × 10⁻³ mM, and 2.7 × 10⁻³ mM. Characterization techniques including XRD, FTIR, SEM, and TEM/EDS analysis confirmed the formation of face-centered cubic AgNPs and amorphous rGO structures. The composites exhibited a firm binding of the surfactant and AgNPs on the surface of rGO nanosheets, resulting in efficient anti-biofilm and photocatalytic activity. The size of the supported AgNPs on rGO/SL was found to be 8–10 nm. The rGS-AgNPs composites displayed significantly improved anti-biofilm and photocatalytic performance, attributed to the increased surface area of AgNPs. Moreover, the photocatalytic efficiency of the rGS-AgNPs composites reached 96.48 % within 60 min, outperforming pure AgNPs. The synthetic procedure and practical applications will be utilized for biosensors, food packing technology, biomedical and pharmaceutically valuable reactions.

Currently the world is facing significant challenges of meeting the rising demands of production of green energy. Clean energy technology development has received a lot of attention because of increasing energy shortages and aggravating environmental degradation. It is critical to address these challenges by developing materials that facilitate carbon-free technologies. MXenes, an emerging member of the 2D nanomaterials family, has distinctive features in terms of clean energy production and storage. This review analyzes various MXenes synthesis methods based on several key factors. The review focuses on MXenes' applications in energy storage devices, particularly in rechargeable batteries and supercapacitors. MXenes exhibit exceptional electrochemical performance due to their high specific surface area, excellent electrical conductivity, and unique interlayer spacing, enabling efficient charge storage and fast ion diffusion. We discuss their implementation as electrode materials in lithium-ion batteries, sodium-ion batteries, lithium-sulphur batteries, metal air batteries and supercapacitors. Moreover, the review examines the applications of MXenes in hydrogen (H₂) production technologies. MXenes have shown tremendous potential as photo/electrocatalysts for water splitting, a key process in renewable hydrogen production. Their unique surface chemistry and tunable electronic properties enable efficient hydrogen evolution reaction (HER) activity. We discuss the recent advancements in developing MXene-based photo/electrocatalysts with their exceptional catalytic performance and durability. Furthermore, we highlight the challenges and prospects associated with MXenes' applications in energy storage and H₂ production. Strategies for improving the stability, scalability, and overall performance of MXenes are discussed. This review not only provides a comprehensive analysis of the recent research efforts but also serves as a guide for future research directions in utilizing MXenes to address the global energy and sustainability challenges.

Absorber thickness is one among keys parameters that can have significant effects on the performance of the solar cell. An appropriate absorber thickness should be chosen to optimize the performance of the cell.The main objective of this work is to offer a perovskite solar cell with high efficiency using a suitable thickness of the active layer. Therefore, this study focuses on the optimization of the solar cell thickness, which can also be achieved by using simulation with SCAPS-1D, to predict the performance of the cell at different thicknesses. In this case, the four main parameters; the short circuit current density, the open-circuit voltage, fill factor and power of conversion efficiency, were extracted and analyzed from I–V characteristics at different thicknesses. In addition, the complex impedance data were also generated by using simulation with SCAPS-1D. To the best of our knowledge, this approach was not used before for many works carried out by SCAPS-1D simulation; where these studies were limited to I-V characteristics. This novel approach to investigating the electrical response of this solar cell concerning thickness involves the integration of complex impedance and modulus functions. This integration enables us to discern the respective contributions of ionic diffusion and recombination processes, through our deconvolution procedure, the results obtained indicate the absorber layer thickness increases, the diffusion and recombination processes are affected differently, subsequently influencing the overall performance of the solar cell. Both methodologies employed in this study consistently identified the maximum efficiency at an optimal thickness of 700 nm.

This research describes the synthesis of the ferroelectric perovskite Na_0.02Bi_0.98FeO_3-δ using a low-cost solid-state method starting from a bismuth ferrite BiFeO₃ structure in order to obtain a material with improved properties for photovoltaic applications. The synthesized materials were characterized by X-ray Diffraction (XRD) technique to determine the effective synthesis conditions for six undoped BiFeO₃ samples obtained at different calcination temperatures and quantified by Rietveld® refinement of diffraction patterns, finding homogeneous phase formation at 810 °C under laboratory conditions. The effective synthesis temperature allowed obtaining a stable perovskite-type material, doped with Na⁺ and its structural characterization by XRD showed a structural modification in the unit cell with respect to BiFeO₃ due to the incorporation of sodium cation. The binding energies determined by X-ray photoelectron spectroscopy (XPS) confirmed the formation of the main crystalline phase and the insertion of Na⁺ cations inside perovskite structure. The morphological characterization by scanning electron microscopy (SEM) of the synthesized material showed the formation of two stable morphologies: Bi₂Fe₄O₉ and Na_0.02Bi_0.98FeO_3-δ as the predominant phase. The optical characterization by Raman spectroscopy allowed identifying variations in the vibration modes of the perovskite doped with respect to undoped bismuth ferrite. The variation of the optical bandgap was determined using the Tauc’s equation and the electrical characterization by solid state electrochemical impedance spectroscopy (SS-EIS) demonstrated an increase in electrical conductivity, at room temperature, by the Na⁺ doped perovskite, proving an optimal behavior for its potential uses as a semiconductor. The results indicate that the current methodology is promising for the low-cost production of Na_0.02Bi_0.98FeO_3-δ type perovskites for photovoltaic applications.

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.