Materials for Renewable and Sustainable Energy最新文献

Designing more effective thermal energy storage devices can result from understanding how air layers impact the melting process. The total efficiency of these systems can be improved by optimizing the melting process of the phase change materials (PCMs), which are utilised to store and release thermal energy. The current study utilises an analysis to evaluate how an air layer would affect melting of the PCM. The enthalpy-porosity combination based ANSYS/FLUENT 16 software is specifically used to accomplish this study, considering the paraffin wax (RT42) as the PCM. The study reveal that the presence of an air layer would impact the dissolution process. This result is assured an increase of melting time of PCM by 125% as a result to having an air layer of 5 cm thickness compared to a cell without an air layer. Furthermore, an increase of the layer thickness beyond 5 cm has a progressive effect on the melting time of PCM. One important component that affects the melting process is the existence of an air layer above the cell. Greater heat transfer resistance from thicker air layers prolongs the time needed to finish melting. The efficient heat transmission of PCM is shown to be reduced when there is an air layer above the cell. The melting process gradually slows down as the air layer thickness rises, which reflects the decreased heat transmission. These results highlight how crucial it is to take the environment into account while creating PCM-filled energy storage cells.

As a result of electrochemical conversion of carbon dioxide (CO₂), value-added chemicals like as synthetic fuels and chemical feedstocks can be produced. In the current state of the art, copper-based materials are most widely used being the most effective catalysts for this reaction. It is still necessary to improve the reaction rate and product selectivity of CuOx for electrochemical CO₂ reduction reaction (CO₂RR). The main objective of this work was synthesized and evaluate the copper oxide electrocatalyst combined with silver (CuO 70% Ag 30%) for the conversion of carbon dioxide into synthetic fuels. The catalysts have been prepared by the oxalate method and assessed in a flow cell system. The results of electrochemical experiments were carried out at room temperature and at different potentials (-1.05 V–0.75 V vs. RHE in presence of 0.1 M KHCO₃) and gas and liquid chromatographic analysis are summarized. The CuOx-based electrodes demonstrated the selective of ~ 25% at -0.55 V for formic acid (HCOOH) and over CuO -Ag and selective of ethylene at ~ 20% over CuOx at -1.05 V. Other products were formed as ethylene, ethanol, and propanol (C₂H₄, EtOH, PrOH) at more positive potentials. On the other hand, carbon monoxide, acetate, ethylene glycol, propinaldehyde, glycoaldehyde and glyoxal (CO, CH₃COO, C₂H₆O₂, C₃H₆O, C₂H₄O₂, C₂H₂O₂) have been formed and detected. Based on the results of these studies, it appears that the formation of synthetic fuels from CO₂ at room temperature in alkaline environment can be very promising.

Microbial fuel cells (MFCs) have attracted a great deal of attention as a promising technology for recovering electricity from organic substances by harnessing the metabolic activities of microorganisms. The objective of this study is to assess the efficacy of a LiTa_0.5Nb_0.5O₃/g-C₃N₄ (LTN/g-C₃N₄) heterojunction as a photocathode catalyst within a single-chamber microbial fuel cell operating under both light irradiation and dark conditions. X-Ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and Energy dispersive X-Ray spectroscopy (EDS) were used to conduct a comprehensive analysis of the composite catalyst, revealing its exceptional purity and unique properties. After 120 h of exposure to visible light, the maximal power density of the MFC containing LTN/g-C3N4-modified carbon cloth was determined to be 667.7 mW/m³. The power density achieved with the presence of light was approximately three times greater than the power density obtained without light in the MFC (235.64 mW/m³). In addition, the study determined that the removal efficiencies of chemical oxygen demand (COD) were 88.4% and 66.5% when exposed to light and in the absence of light, respectively. These findings highlight the potential of the non-precious LTN/g-C₃N₄ photocatalyst as a viable alternative for effective wastewater treatment and power generation in microbial fuel cells with a single chamber configuration.

Several studies on solar cells using SCAPS-1D were conducted to investigate their performance, which are typically limited to I–V analysis for DC characterization. Therefore, in the present study, a very wide frequency range from 10^–2 Hz to 10¹² Hz was employed to explore diffusion processes and investigate the performance of lead-free Perovskite Solar Cells (PSCs) featuring as a novel heterostructure. These investigations concern the optimization of MASnI₃ thickness as an absorber. Additionally, the impact of series (Rs) and shunt (Rsh) resistances is also examined. From the I–V analysis, it was determined that the power efficiency (PCE) could be achieved at a thickness of 0.6 µm. Increasing the series resistance (Rs) led to a significant decrease in the fill factor (FF) and (PCE), whereas the shunt resistance (Rsh) demonstrated a notable improvement in both (FF) and (PCE). Analysis of AC characteristics revealed complex impedance (Z*) and modulus (M*) indicative of main ionic transport, recombination, and diffusion processes crucial for optimization. An appropriate equivalent circuit model was developed and validated through deconvolution and theoretical considerations, yielding parameters such as the time constant for each process. It was observed that ionic conductivity and electronic diffusion play key roles in balancing charge collection and recombination losses. The critical influence of series and shunt resistance on low and high-frequency processes was emphasized, underscoring their significance in solar cell efficiency. A strong correlation was established between the evolution of time constants for each process and power conversion efficiency (PCE).

Single lithium-ion conducting polymer electrolytes are promising candidates for next generation safer lithium batteries. In this work, Li⁺-conducting Nafion membranes have been synthesized by using a novel single-step procedure. The Li-Nafion membranes were characterized by means of small-wide angle X-ray scattering, infrared spectroscopy and thermal analysis, for validating the proposed lithiation method. The obtained membranes were swollen in different organic aprotic solvent mixtures and characterized in terms of ionic conductivity, electrochemical stability window, lithium stripping-deposition ability and their interface properties versus lithium metal. The membrane swollen in ethylene carbonate:propylene carbonate (EC:PC, 1:1 w/w) displays good temperature-activated ionic conductivities (σ ≈ 5.5 × 10^–4 S cm⁻¹ at 60 °C) and a more stable Li-electrolyte interface with respect to the other samples. This Li-Nafion membrane was tested in a lithium-metal cell adopting LiFePO₄ as cathode material. A specific capacity of 140 mAhg⁻¹, after 50 cycles, was achieved at 30 °C, demonstrating the feasibility of the proposed Li-Nafion membrane.

Low-sulfonation-level polyether sulfone octyl sulfonamide (LSPSO) was blended with a layered double hydroxides (LDHs, Mg₂AlCl)/sepiolite nanostructure clay as a filler to create an electrolyte membrane for fuel cell applications. Comprehensive characterization of the composite membranes was conducted, encompassing Fourier-transform infrared spectroscopy, X-ray diffraction, mechanical stability assessment, thermal gravimetric analysis, ion exchange capability, swelling characteristics, water uptake performance, and electrochemical impedance spectroscopy analysis. In comparison to the pristine LSPSO membrane, the presence of LDHs/sepiolite nanoarchitecture material within LSPSO exhibited superior water retention and proton conductivity values, especially at elevated temperatures. The proton conductivity of the composite membranes reached approximately 250 mS/cm, while the unmodified LSPSO membrane only achieved 35 mS/cm at 100 °C. Moreover, LSPSO composite membranes demonstrated enhanced chemical and thermal stability along with higher proton conductivity when compared to pristine LSPSO membranes. These findings highlight the potential of developing tailored LSPSO composite membranes to advance the prospects of commercial applications in proton exchange membrane fuel cells.

Climate change and global warming problem are becoming the serious issue and some action is necessary in order to mitigate the rising temperature. CO₂ increase is one of the reason for temperature rise, and the technology to convert CO₂ to beneficial energy or chemical substance could be one of the key solution (CO₂ photocatalytic reduction). Metal–organic frameworks (MOFs) have gained much attention owing to their extremely large surface areas, tunable fine structures, and potential applications in many areas. Recently, MOFs have been demonstrated to be promising materials for CO₂ photocatalytic reduction. This review summarized recent research progresses in photocatalytic reduction using MOFs. MOFs were classified mainly by the type of metal center, and the feature and tendency against their functions towards CO₂ photocatalytic activity will be explained.

An innovative methodology was employed to fabricate ion exchange membranes tailored for fuel cell applications. This approach entailed blending low sulfonated polyether sulfone octyl sulfonamide (LSPSO) with Hectorite (Hect) clay at varying weight percentages (1 wt%, 3 wt%, and 6 wt%). The resultant composite membranes underwent comprehensive characterization via Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and thermogravimetric analysis, aiming to assess their surface morphology and thermal resilience. Remarkably, the thermal stability of the composite membrane exhibited a substantial enhancement in comparison to the pristine LSPSO membrane. Moreover, the incorporation of 6 wt% Hectorite into the composite membrane yielded a noteworthy amplification in proton conductivity, achieving a fourfold increase (141.66 mS/cm) as opposed to the LSPSO membrane in isolation (35.04 mS/cm). Consequently, the Hect/LSPSO composite membrane exhibits remarkable potential as an electrolyte membrane for fuel cells operating at temperatures surpassing 100 °C.

Self-assembly is the most promising low-cost and high-throughput methodology for nanofabrication. This paper reports the optimization of a self-assembly process at room temperature for the growth of copper oxide (CuO) based nanostructures over a copper substrate using aqueous potassium hydroxide (KOH) solution as the oxidizing agent. The monoclinic phase of CuO nanostructures grown over the copper substrate was confirmed from the X-ray diffraction (XRD) and micro-Raman analysis. The overall chemical composition of nanostructures was confirmed to be that of CuO from its oxidation state using X-ray photoelectron spectroscopy (XPS). Photodetectors were engineered with the structure Cu/CuO/Ag. The photodetectors exhibited a response to both ultraviolet and visible light illumination. The optimized Cu/CuO/Ag structure exhibits a responsivity of ~ 1.65 µA/W, with an ON:OFF ratio of ~ 69 under a bias voltage of 0.01 V. The temporal dependence of photo-response for the optimized photodetector displayed the persistent nature of photoconduction indicating a delay in charge carrier recombination which could potentially be exploited for photovoltaic applications.

Perovskite solar cells (PSCs) are currently demonstrating tremendous potential in terms of straightforward processing, a plentiful supply of materials, and easy architectural integration, as well as high power conversion efficiency (PCE). However, the elemental composition of the widely utilized organic–inorganic halide perovskites (OIHPs) contains the hazardous lead (Pb). The presence of Pb in the PSCs is problematic because of its toxicity which may slow down or even impede the pace of commercialization. As a backup option, the scientific community has been looking for non-toxic/less-toxic elements that can replace Pb in OIHPs. Despite not yet matching the impressive results of Pb-containing OIHPs, the community is paying close attention to Pb-free materials and has seen some encouraging findings. This review evaluates the Pb-replacement with suitable elements and scrutinizes the desirable optoelectronic features of such elements in OIHPs. The fundamental features of Pb-free OIHPs together with their photovoltaic performance in the PSCs are evaluated in details. Finally, we sum up the current challenges and potential opportunities for the Pb-free OIHPs and their devices.