Materials for Renewable and Sustainable Energy最新文献

Sulfonated poly (ether ether ketone) (SPEEK) has received substantial attention for its potential to improve the electrochemical behavior and thermomechanical capabilities of direct methanol fuel cells. This study examines how the integration by solution casting of microcrystalline cellulose (MCC) and 2,3-dialdehyde cellulose (DAC) onto highly sulfonated PEEK (with a sulfonation degree of 80%) affects its physicochemical properties and morphological structures. The mechanical attributes and proton conductivity of the polymer matrix are impacted by MCC and DAC inclusion into SPEEK membrane. The maximum proton conductivity was seen in the SPEEK/MCC membranes at 70 °C (up to 0.1 S cm⁻¹). The proton conductivity in methanol vapor was increased by SPEEK/DAC membranes at high temperatures as opposed to pristine SPEEK and SPEEK/MCC membranes.

Microelectromechanical systems (MEMS) offer its ability to sense, control and actuate on sub-micron scale and exhibit its effect on macro scale. To implement any specific MEMS system, small, efficient and long-lifespan micro power sources are required. Piezoelectric energy harvester (PEH) along with radioactive source is one of the most promising approaches to harness electrical energy at micro to millimeter range. In this report, a scandium (Sc) doped Aluminium Nitride (AlN) unimorph piezoelectric energy harvester has been demonstrated. Unimorph piezoelectric layer is built on Silicon Nitride (Si₃N₄) substrate platform that act as cantilever beam and that can be vibrated by inbuilt radioactive system. In particular, Si₃N₄ as cantilever material and the impact of Sc doping concentration on electrical and mechanical properties of AlN piezoelectric thin film materials have been studied in MATLAB simulation platform. Results obtained from numerical study suggests that the proposed energy harvester model composed of AlScN unimorph piezoelectric (with 10% Sc doping concentration, Sc-10%) layer and Si₃N₄ cantilever can yield a maximum power output of ~ 19.33 μW and overall mechanical energy conversion efficiency of ~ 91.07%. These are the maximum output power and mechanical energy conversion efficiency numerically obtained from Sc doped AlN piezoelectric energy harvester systems to the best of our knowledge.

Developing supercapacitor materials that are both efficient and durable, with high cycle life and specific energy, poses a significant challenge due to issues in electrodes such as volume expansion and electrode degradation that occur over time. This work reports a simple, novel, and cost-effective synthesis method to fabricate high surface area “Iron (Fe) doped TiO₂ materials” via the metal-organic framework (MOF) route for supercapacitor application. Morphological analysis revealed a disc-like shaped pattern for pristine TiO₂ (PT), and a cuboid form for Fe-doped TiO₂ (FeT). The electrochemical investigation of MOF-derived PT and FeT electrode materials demonstrated the superior performance of FeT. Cyclic Voltammetry revealed enhanced electrochemical properties in FeT. Galvanostatic charge-discharge measurements confirmed FeT’s higher energy storage capacity, reaching a maximum specific capacitance of 925 Fg^− 1. Long-term cycling tests exhibited excellent stability, with FeT retaining 67% of its initial capacitance after 6000 cycles and showing prolonged self-discharge. Overall, the results underscore the potential of Fe-doped TiO₂ for high-performance supercapacitors.

Using the renewable energy, especially solar energy, is an environmental-friendly approach for seawater desalination. Solar evaporation is a promising freshwater harvesting strategy rich in energy, including solar and water energy. Herein, we propose a solar evaporation hybrid hydrogel including polyvinyl alcohol (PVA) and glutaraldehyde (GA) as a polymer network, semiconductor oxide nanoparticles (ZnO, CuO) and activated carbon as a photothermal material. Structural properties of hybrid hydrogel were characterized by X-ray diffraction (XRD) analysis, surface morphology by field emission scanning electron microscope (FE-SEM), chemical bonding by Fourier transform infrared spectroscopy (FTIR) and optical absorption and absorption coefficient (α) of components by UV–Vis spectroscopy. The result showed in visible region, PVA:ZnO:AC hydrogel nanocomposite has a strong absorption (55%) compare of the PVA:CuO:AC hydrogel nanocomposite (35%). In addition, by distillation measurements, the evaporator system demonstrated for PVA:CuO:AC and PVA:ZnO:AC Hydrogel an evaporation rate of 2.29 kg m⁻² h⁻¹ and 5.19 kg m⁻² h⁻¹ with the evaporation efficiency of 30.66% and 70.80%, respectively, under 0.1 sun irradiation. For PVA:CuO:AC hydrogel, the hardness of Caspian seawater decreased from 6648 to 115 ppm and ion conductance from 8641 (μS) to 244 (μS) and for the PVA:ZnO:AC Hydrogel decreased to 97 ppm and ion conductance to 206 (μS). Experiments showed that with changing type of the ZnO or CuO semiconductor oxide nanoparticles can effectively on regulate the optical properties of the evaporator. Eventually, this work begins a new point of synthesizing cost-effective photothermal absorbers based on metal oxides material and activated carbon nanocomposite.

The energy consumption for cooling takes up 50% of all the consumed final energy in Europe, which still highly depends on the utilization of fossil fuels. Thus, it is required to propose and develop new technologies for cooling driven by renewable energy. Also, thermal energy storage is an emerging technology to relocate intermittent low-grade heat source, like solar thermal energy and industrial waste heat as well as to exploit off-peak electricity, for cooling applications. This review aims to summarize the recent advances in thermally driven cooling and cold storage technologies, focusing on the formation and fabrication of adopted composites materials, including sorption materials, phase change materials, and slurries. Herein, first the classifications, selection criteria, and properties for these three types of materials is discussed. Then, the application potentials of all the materials are prospected in terms of economic analysis and sustainability.

Extending the operation of proton exchange membrane fuel cells (PEMFCs) at high temperature (i.e., 120 °C) and/or low relative humidity (< 50% RH) remains a significant challenge due to dehydration and subsequent performance failure of the Nafion electrolyte. We approached this problem by integrating the Nafion matrix with a novel hybrid nanofiller, created through direct growth of TiO₂ nanoparticles on the surface of carbon nanotubes. This synthetic approach allowed to preserve an effective nanodispersion of Titania particles in the hosting matrix, thereby boosting dimensional stability, hydrophilicity, and physiochemical properties of the Nafion/MWCNTs-TiO₂ (NMT-x) nanocomposites compared to parental Nafion. At optimal concentration (i.e., 3 wt% with respect to the polymer), the nanocomposite membrane exhibited high transport characteristics with impressive water retention capabilities, resulting in a proton conductivity of 8.3 mS cm^− 1 at 80 °C and 20% RH. The Titania nanoparticles plays a key role in retaining water molecules even under dehydrating conditions, while also directly contributing to proton transport. Additionally, the long carbon nanotubes promote the formation of additional paths for proton conductivity. These combined features enabled the NMT-3 membrane to achieve a maximum power output of 307.7 mW/cm² in a single H₂/air fuel cell (5 cm² active electrode area and 0.5 mg Pt/cm² at both electrodes) under very challenging conditions, specifically at 120 °C and 30% RH. This represents a significant advancement towards overcoming the limitations of traditional Nafion membranes and opens up new possibilities for high-temperature, low-humidity H₂/air fuel cell applications.

Triboelectric nanogenerators (TENGs), a new technology for gathering sustainable energy, have attracted much scientific interest. In this study, we describe a unique method for modifying the triboelectric power generation performance of Polyvinyl Alcohol (PVA) by adding ZnO–CuO–AgO (ZCA) trimetallic nanoparticles to improve the performance of TENGs and answer the requirement for ecologically benign and biodegradable materials. Hydrothermal synthesis adopted to create ZnO–CuO–AgO trimetallic nanoparticles ensures a distinctive structure with a large surface area, essential for enhancing triboelectric power generation. From the AFM results, it is evident that 1% PVA/ZCA showed the highest output voltage of 0.27V. Despite following the general trend, at higher concentrations of ZCA nanofiller in the PVA matrix, the enhancement of output voltage is not observed, which can be attributed to the non-uniform distribution. The effect of spin-coated film thickness and nanoparticle concentration on the triboelectric performance of the PVA nanogenerator is studied by monitoring the open-circuit voltage in response to various mechanical stimuli. Finally, the developed biodegradable nanogenerators in this study can be used for sustainable energy harvesting applications such as wearable electronics, self-powered sensors, and environmental monitoring systems.

This work presents the synthesis and evaluation of Pd-Ni aerogels toward the urea oxidation reaction (UOR). The incorporation of Ni led to a 0.13 V reduction in the energy required for the oxidation and reduction of PdO compared to monometallic Pd, both in alkaline medium with and without urea. Varying the Ni ratios in Pd (Pd-Ni 4:1, Pd-Ni 1:1, and Pd-Ni 1:4) led to significant changes in the electrochemical behaviour. In alkaline medium without urea, PdNi 4:1 showed the formation of NiOOH at 1.35 V, which promoted oxygen diffusion on the electrode surface and increased the current density, confirming the increase in the active sites of NiOOH and NiPdOOH and enabling urea-based electrolysis at these sites. While palladium aerogels alone are ineffective for UOR, the presence of nickel plays a key role in enhancing the UOR efficiency. On the other hand, physicochemical characterisation revealed that PdNi 4:1 has a crystal size of 4.37 nm and a larger shift in the 2θ positions of the (111) and (200) planes, which favours electronic changes that were investigated by XPS. These changes affected the electrocatalytic activity, which is primarily related to electronic effects. The results of SEM and TEM studies and nitrogen adsorption-desorption isotherm confirmed that the aerogels are highly porous and have an effective surface area and abundant active sites for reactions that allow efficient mass transfer and low diffusion resistance. TEM observations revealed interconnected nanochains indicating optimal electrocatalytic activity for both ORR and UOR due to high mass transfer. These interconnected networks are crucial for improving electrocatalytic activity in the urea oxidation reaction.

Rice husks are not readily biodegradable making their disposal challenging due to the common disposal method of open burning which has negative environmental effects. Additionally, banana, sweet potato and cassava peelings form a large percentage of organic municipal solid waste. Therefore, this study developed rice husk biochar briquettes with organic municipal peelings waste as binders. Rice husks biochar was formed via carbonization processes in a step-down kiln at temperatures ranging between 400 and 500 °C. Organic binders were mixed with the rice husk biochar at different ratios of 10% and 15% before being compacted at a pressure ≤ 7 MPa into briquettes. Thermogravimetric results showed that the developed briquettes had high ash contents ranging from 44% to 47%. Rice husk biochar briquettes with the highest particle density were observed for briquettes with 15% cassava peel binder at 427.1 kg/m³. The highest HHV and maximum attainable flame temperature of 21.75 MJ/kg and 828.7 °C were obtained for rice husk biochar briquettes with 15% matooke peeling organic binder. For all rice husk biochar briquettes, increasing the organic peeling binder had a positive impact of reducing the ash content, while at the same time increasing the peak temperatures, thus contributing to their enhanced thermal stability.

Hierarchical hollow urchin-like nickel cobaltite (NiCo₂O₄) was synthesized using a two-step hydrothermal method. The effects of metal composition and surfactant addition on the morphology, structure, and electrochemical performance toward oxygen evolution reaction (OER) were investigated. The addition of cetyltrimethylammonium bromide (CTAB) reduced particle aggregation, resulting in a higher electrochemical active surface area and electrical conductivity. Lowering the Ni content from 1.0 to 0.25 did not alter the morphology and structure of the product to any extent. However, the crystallite size slightly increased. Among the spinels with different Ni and Co compositions, NiCo₂O₄ exhibited a superior OER electrocatalytic activity, achieving a 380 mV overpotential at 10 mA/cm² current density. It also delivered a good performance in an anion exchange membrane water electrolyzer (AEMWE) using 1 M NaOH at 60 °C, reaching a current density of about 420 mA/cm² at a cell voltage of 1.95 V.