Materials for Renewable and Sustainable Energy最新文献

Biomass is a renewable and CO₂-neutral energy source. However, the efficiency of biomass combustion plants remains lower than that of current fossil fuel-based systems. To minimize corrosion from aggressive species found in biomass combustion, these plants currently operate at a maximum temperature of 550 °C. The European project BELENUS explored new materials and coatings to raise the operating temperature to 600 °C, thereby improving plant efficiency. Among the coatings under investigation, a super high-hardness steel (SHS) modified with Al, applied by high velocity oxy-fuel (HVOF) thermal spray on ferritic steel SVM12, has demonstrated an improved performance in the laboratory, exposed to a model biomass environment containing KCl deposits for 8000 h at 600 °C. Microstructural analysis by field emission scanning electron microscopy (FESEM) and X-ray diffraction was conducted on the tested samples to examine the coating’s evolution in these environments, as well as the associated protection and degradation mechanisms. The presence of Al within the coating significantly enhanced its resistance to biomass corrosion when compared to uncoated SVM12 and the Al-free SHS coating. Possible reasons for the improved behaviour of the Al-modified coating are the reduction of porosity as well as the blocking effect of either intermetallic FeAl or Al oxide which forms at the splat boundaries prior to exposure to the corrosive atmosphere.

The global challenge of reducing greenhouse gas emissions has driven the development of clean energy technologies, with hydrogen emerging as a key vector for decarbonization. However, its low volumetric density poses significant challenges for efficient compression and storage. In this context, electrochemical hydrogen compressors (EHCs) have emerged as a promising alternative to traditional mechanical systems, offering high energy efficiency, operation without movement of parts, and simultaneous purification capabilities. This review explores the operational principles of EHCs and provides a detailed analysis of their critical components, with particular emphasis on the membrane-electrode assembly (MEA), including polymer membranes and electrocatalysts. The most relevant advances between 2020 and 2025 are systematized, comparing structural properties, electrochemical performance, and novel materials efficiency. Among the key findings, it is highlighted that thin and reinforced membranes enhance energy performance, while bimetallic or non-noble catalysts offer viable solutions to the high cost of platinum. This analysis identifies emerging technological trends and provides clear guidelines for the design of more efficient, durable, and scalable EHC systems.

Chitosan, a natural polymer, is gaining attention for its low cost, hydrophilicity, and environmental benefits, making it a promising material for polyelectrolyte membranes (PEMs) in fuel cells (FCs). In this study, four membranes were fabricated using sulfonated chitosan combined with three sulfonated nanoparticles: sulfonated titanium dioxide (STiO₂), sulfonated silicon dioxide (SSiO₂), and sulfonated carbon nanotubes (SCNT) in varying ratios. The optimal membrane was prepared using a specific ratio of these components, cross-linked with 0.5% glutaraldehyde. While the electrochemical performance improved with increasing nanoparticle ratios, excessive nanoparticle content led to diminished results. The optimal membrane demonstrated excellent stability at 50 °C, achieving a maximum power density of 90 mW/cm² at 280 mA/cm² and a low cell resistance of 5.1 Ω cm². Compared to the chitosan (CS)-based membranes in the literature, the optimal membrane exhibited superior ion exchange capacity, proton conductivity, mechanical stability, and lower water uptake, highlighting its potential as a sustainable and high-performance proton exchange membrane in fuel cell applications.

This review critically evaluates recent advancements in electrocatalytic technologies aimed at enhancing the efficiency of metal-supported Solid Oxide Fuel Cells (SOFCs) for biofuel-powered mobility applications. The study aims to elucidate the impact of these innovations on the performance, durability, and stability of SOFCs in transportation and portable energy systems. By integrating experimental findings, computational simulations, and practical applications, this work highlights the pivotal role of advanced electrocatalysts in optimizing SOFC functionality. Key developments, such as the incorporation of perovskite-based materials and exsolved nanoparticle catalysts, have demonstrated remarkable improvements in electrochemical performance and operational longevity. Specifically, lanthanum-strontium cobalt ferrite (LSCF)-based cathodes demonstrated a 30% increase in power output and a 25% enhancement in long-term stability under biofuel operating conditions. Furthermore, computational modeling has played a crucial role in refining catalyst designs, achieving a 45% reduction in degradation rates. These advancements underscore the potential of biofuel-driven SOFCs as a sustainable energy solution for transportation. However, future research must address challenges related to scalability, cost-effectiveness, and economic competitiveness to fully realize their practical implementation.

The valorisation of plastic waste through diverse recycling technologies offers a strategic response to the escalating global plastic crisis, combining waste reduction with resource and energy recovery. This review critically examines both conventional and emerging methods—including mechanical recycling, incineration for energy recovery, pyrolysis, gasification, hydrogenation, hydrocracking, and solvent-based treatments—focusing on their technical efficacy, environmental footprint, and economic feasibility. Mechanical recycling remains the most widely adopted method, involving collection, sorting, grinding, washing, drying, and granulation processes. However, challenges such as polymer degradation, contamination, and incompatibility among mixed plastics limit the quality and applicability of recycled products. Advanced sorting technologies, including Near-Infrared (NIR) spectroscopy, Artificial Intelligence (AI), and electrostatic separation, are increasingly employed to enhance recycling outcomes. Incineration provides energy in the form of electricity, heat, or steam while significantly reducing waste volume, yet it raises environmental concerns due to the release of toxic gases and particulates. Chemical recycling emerges as a critical pillar of the circular plastic economy, enabling the breakdown of polymers into valuable chemical feedstocks. Techniques such as pyrolysis, gasification, and hydrocracking produce valuable by-products, including char, syngas, and bio-oil. The review underscores the potential of integrating incineration with carbon capture technologies to mitigate emissions and improve sustainability. It advocates for region-specific strategies supported by comprehensive techno-economic and environmental assessments. This work provides a comparative framework to inform the selection of recycling technologies, guide policy development, and identify research priorities in advancing plastic waste valorisation.

This study systematically compares the microstructural characteristics, surface morphology, and corrosion resistance of Ni-Sn alloy coatings electrodeposited using direct current (DC) and pulse current (PC) methods. The influence of waveform geometry – including triangular, rectangular, sinusoidal, and ramp configurations – on coating properties was comprehensively characterized through microhardness testing, X-ray diffraction (XRD), scanning electron microscopy (SEM), potentiodynamic polarization (PDP), and electrochemical impedance spectroscopy (EIS) analyses. These techniques respectively evaluated the mechanical properties, phase composition, morphological features, and electrochemical corrosion behavior of the deposited coatings. X-ray diffraction (XRD) analysis revealed that the coatings consisted predominantly of the Ni₃Sn₂ intermetallic phase. Scanning electron microscopy (SEM) examination demonstrated that the Ni-Sn coating deposited using PC current exhibited superior surface uniformity but lower density compared to the direct current (DC) deposited coating. Microhardness measurements showed an increase from 238 HV (DC) to 297 HV for the ramp-wave PC coating. Electrochemical impedance spectroscopy revealed substantial improvements in charge transfer resistance (Rct), with PC-deposited coatings showing increases of 1570% (ramp), 554% (sinusoidal), 324% (triangular), and 83% (rectangular) relative to DC coatings. Correspondingly, potentiodynamic polarization measurements demonstrated that the corrosion current density (icorr) was reduced by factors of 14.5 (ramp), 3.2 (sinusoidal), and 2.9 (triangular) compared to the DC-deposited coating. Ultimately, PC plating yielded Ni-Sn alloys with improved corrosion resistance across all waveforms (ramp, sinusoidal, triangular, DC). This suggests promise for these advanced coatings in microelectronics and energy storage.

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The development of high-performance proton exchange membranes (PEMs) is crucial for advancing fuel cell technology, particularly under demanding operating conditions. This study investigates novel nanocomposite membranes based on Nafion reinforced with sulfonated clay-carbon nanotubes (sCC) as a hybrid filler. The incorporation of sCC not only improved the ion exchange capacity and hydrolytic stability but also critically modulated water dynamics, leading to superior water retention and sustained proton diffusion, particularly at elevated temperatures. The nanocomposite membranes exhibited substantially higher proton conductivity, especially under low relative humidity conditions, a critical factor for high-temperature fuel cell operation. Electrochemical evaluation in a H₂/O₂ direct hydrogen fuel cell (DHFC) showed an almost fourfold increase in peak power density (443.2 mW cm⁻²) under challenging high-temperature, low-humidity conditions (120 °C, 20% RH) for N-sCC-L3 compared to recast Nafion (117.3 mW cm⁻²).

Water management is crucial for the performance of anion exchange membrane water electrolyzers (AEM-WEs), to maintain membrane hydration and enable phase separation between hydrogen gas and liquid water. Therefore, careful material selection for the anode and cathode is essential to enhance reactant/product transport and optimize water management under ‘dry cathode’ conditions. This study investigates the wetting characteristics of two commercially available porous transport layers (PTLs) used in AEM-WE: carbon paper and carbon paper with a microporous layer (MPL). Wettability was measured under static, quasi-static, and dynamic conditions to assess the effect of water and electrolytes (NaOH, KOH, K₂CO₃) across concentrations (up to 1 M) and operational temperatures (20 °C to 92 °C). Carbon paper exhibits mild hydrophobicity (advancing contact angles of (:sim)120°, however with receding contact angle (:sim)0°), whereas carbon paper with MPL demonstrates superhydrophobicity (advancing and receding contact angles >145° and low contact angle hysteresis), maintaining a stable Cassie-Baxter wetting state. Dynamic wetting experiments confirmed the robustness of the superhydrophobicity in carbon paper with MPL, facilitating phase separation between hydrogen gas and liquid water. The presence of supporting electrolytes did not significantly affect wettability, and the materials retained hydrophobic properties across different temperatures. These findings highlight the importance of MPLs in optimizing water transport and gas rejection within AEM-WEs, ensuring efficient and stable operation under “dry cathode” conditions. These PTLs (with and without the addition of the MPL) were integrated into AEM-WE and polarization curves were run. Preliminary data, in a specific condition, suggested the presence of the MPL within the PTL enhance AEM-WE performance.

In this work, titanium dioxide nanoparticles (TiO₂ NPs) were green-synthesized using jasmine (Jasminum sambac) flower extracts as the medium with different solvent variation concentrations. The green synthesis was carried out using titanium isopropoxide (TTIP) as a precursor via the sol-gel method. The obtained TiO₂ NPs were characterized using infrared spectroscopy (FTIR), ultraviolet spectroscopy (UV-DRS), X-ray diffraction (XRD), field emission scanning electron microscopy/energy dispersive X-ray spectroscopy (FESEM/EDX), Raman spectroscopy, and high-resolution transmission electron microscopy/selected area diffraction (HRTEM/SAED). The characterization revealed that the green-synthesized TiO₂ NPs possess a pure tetragonal anatase phase, which belongs to the space group I4₁/amd. Dye-sensitized solar cell devices were further fabricated using the obtained TiO₂ NPs and sensitized with the commercial dye N719 and a kesumba (Bixa orellana) seed extract as an alternative, inexpensive, yet sustainable natural dye. The highest efficiency of 2.52% was obtained from TiO₂ NPs sensitized using commercial dye N719 and synthesized using jasmine flower extract containing 30% acetylacetone, followed by one containing 50% acetylacetone, which is higher than that of commercial TiO₂ (0.80%). The same materials sensitized using kesumba seed extract resulted in efficiency of 0.22%, 0.08%, and 1.22%, respectively. These findings offer insight and pave the way for more novel, environmentally friendly methods for developing green-synthesizing nanomaterials and natural dye derivatives, ultimately contributing to a sustainable future.

This study explores the utilization of fabricated piezoelectric polyvinylidene fluoride nanofiber (NF-PVDF) materials in wearable electronic sensing applications by investigating their current-voltage ((:I-V)) characteristics under controlled ultra-low-frequency excitation forces. The results demonstrate a significant power harvesting capability, achieving an output power of 0.12 µW/mm² at an operating point of 5.04 V and 7.7 µA. Additionally, the piezoelectric harvester was integrated into a charging-discharge circuit alongside a rectifier capacitor and a typical IoT wearable sensor, leveraging the advantages of a flexible substrate. Experimental measurements of the charging and discharging curves confirm the effective energy management of the system, indicating a robust potential for deployment in real-world sensing applications. These findings highlight the promising application of NF-PVDF in sustainable energy harvesting for next-generation wearable technologies.