Materials Science for Energy Technologies最新文献

Titanium dioxide (TiO₂) nanoparticles are commonly used as photoanode materials in dye-sensitized solar cells (DSSC). The structure of TiO₂ can be modified by doping to enhance its optical and electrical performance. The modification carried out in this research was by providing Ag doping on TiO₂. Silver (Ag) added to TiO₂ is convinced to reduce the recombination and increase the energy level of the photo-excited electrons from the TiO₂ conduction band. Ag-doped TiO₂ was carried out by a simple mixing method. The microstructure of Ag-doped TiO₂ was successfully characterized by XRD and SEM. The absorbance of the Ag-doped TiO₂ thin films was measured by UV–Vis spectroscopy, confirming the optimum energy gap of 3.09 eV and resulting in the best PCE of 6.31 %.

With the help of a hydrothermal process, we were able to prepare vertically layered MoS₂ nanoflakes that were rooted to TiO₂ modified. MoS₂ nanoflakes and TiO₂ contribute significantly to the strong XRD peaks and μ-Raman spectroscopy, and this phenomenon may also be explained by the unique structure of vertically stacked MoS₂ nanoflakes on TiO₂ that has many exposed edges and large surfaces as well as high electron transfer rates between TiO₂ and MoS₂. As can be clearly seen, there are no noticeable changes in the self-photodegradation of MB under visible light interaction (VLI), and the MoS₂ doped TiO₂ photocatalyst displays ∼ 90 % degradation efficiency. By, measuring photoelectrochemically, charge carriers are separated efficiently. These experiments illustrate the transient photocurrent response of the MoS₂ doped TiO₂ photocatalyst while cycling between three on/off cycles. As a result of a low recombination rate of the photoexcited charge carriers, the MoS₂ doped TiO₂ photocatalyst displays superior photocurrent response. In other words, a lower charge transfer resistance results in a faster transfer of charge between the surfaces.

In this study, the influence of p-type doping with Na atoms on the optical bandgap and electrical conductivity of a series of bismuth ferrites (BiFeO₃) synthesized by a low-cost solid-state method was evaluated. To identify the properties that influenced the bandgap and electrical response of the samples, the phase of interest was identified and quantified by X-ray diffraction (XRD), the morphological characteristics were determined by scanning electron microscopy (SEM). Structural properties were elucidated by spectroscopic techniques and finally the optical response (indirect bandgap) was measured by ultraviolet–visible spectroscopy (UV–Vis) and electrical response (conductivity) by solid-state electrochemical impedance spectroscopy (SS-IES). The results of this work demonstrated that the optical and electrical response of the series of Na-doped BiFeO₃ samples is dependent on at least eight structural and morphological variables (sodium ratio, purity, unit cell volume, oxygen vacancy concentration, crystalline domain size, structural microdeformations, particle size and Warburg-type resistive phenomena). Among the most relevant results, the influence of purity, intrinsic and physical defects was identified, observing a decrease of the electrical resistance and energy gap with the presence of Na.

The solid-state zinc-ion battery (ZIB) is environmentally friendly, cost effective, and extremely safe, which are essential features for alternative sustainable energy storage systems. Herein, a polymer composite electrolyte (PCE) is successfully developed through a facile solution-casting approach from a thermo-responsive copolymer-based electrolyte and layered ternary carbide (Ti₃AlC₂). The thermo-responsive copolymer demonstrated synergistic mechanical properties through the addition of an appropriate plasticizer and a zinc salt. This combination suggests that the material possesses thermal self-protection capabilities due to its anti-Arrhenius ionic-conducting behavior. However, parasitic reactions and dendrite formation hindered the achievement of its full potential. The incorporation of Ti₃AlC₂ or MAX phase can mitigate the above obstacles, enhancing electrochemical performance with excellent flexibility and maintainable self-extinguishing. The solid-state ZIB benefits from the well-designed PCE with the expanding layer interspacing, delivering a remarkably high capacity (336 mAh g⁻¹ at 0.1 A g⁻¹) and energy density of 242 Wh kg⁻¹. This is achieved due to the Ti₃AlC₂′s ability to immobilize or entrap triflate anions via electrostatic forces. Therefore, the designed PCE is a promising step toward the development of flexible solid electrolytes in ZIBs.

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.