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•A green and cost-effective method to convert sugarcane bagasse into aerogel has been developed.•Sugarcane bagasse aerogel is a promising candidate for heat insulation ...applications.•Sugarcane bagasse aerogel is a promising candidate for oil-spill cleaning applications.•Sugarcane bagasse aerogel is highly flexible, and can be bent without breaking.
A promising and economic material for various applications, such as thermal insulation in construction building and oil clean-up in marine ecosystems, is successfully developed from the by-product of the sugarcane industry. Biodegradable sugarcane bagasse aerogels are produced using polyvinyl alcohol (PVA) binder, followed by a freeze-drying method. This environmental-friendly recycled aerogel has an ultra-low density (0.016-0.112 g/cm3), a high porosity (91.9–98.9%), and a very low thermal conductivity (0.031-0.042 W/mK). Its superhydrophobicity properties and its maximum oil absorption capacity (up to 25 g/g) are measured after coating aerogel samples with methyltrimethoxysilane (MTMS). The biodegradable aerogel has a Young's modulus of 88 K Pa and can be bent without breaking, demonstrating its high flexibility.
Rechargeable lithium ion batteries have ruled the consumer electronics market for the past 20 years and have great significance in the growing number of electric vehicles and stationary energy ...storage applications. However, in addition to concerns about electrochemical performance, the limited availability of lithium is gradually becoming an important issue for further continued use and development of lithium ion batteries. Therefore, a significant shift in attention has been taking place towards new types of rechargeable batteries such as sodium-based systems that have low cost. Another important aspect of sodium battery is its potential compatibility with the all-solid-state design where solid electrolyte is used to replace liquid one, leading to simple battery design, long life span, and excellent safety. The key to the success of all-solid-state battery design is the challenge of finding solid electrolytes possessing acceptable high ionic conductivities at room temperature. Herein, we report a novel sodium superionic conductor with NASICON structure, Na3.1Zr1.95Mg0.05Si2PO12 that shows high room-temperature ionic conductivity of 3.5 × 10(-3) S cm(-1). We also report successful fabrication of a room-temperature solid-state Na-S cell using this conductor.
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•Recycled fibers from car tire waste developed successfully into rubber aerogels•Aerogels have low density, highly porous but are much stiffer than Styrofoam•MTMS coating converts ...completely their hydrophobicity to super hydrophobicity•Excellent sound adsorption, high flexibility and low thermal conductivity•Versatile rubber aerogels are for several high-value engineering applications
For the first time, recycled car tire fibers (RCTF) shredded from car tire waste are developed successfully into a novel material, a rubber aerogel, using polyvinyl alcohol (PVA) and glutaraldehyde (GA) as crosslinkers through a cost-effective freeze-drying method. Its structure and main physical properties are investigated comprehensively for high-value applications, such as heat and sound insulation of buildings and oil spill spilling clean up. The rubber aerogel has ultra-low density (ρa = 0.035 – 0.145 g/cm3) and high porosity (Φavg = 84.31–96.20 %). With a simple but effective coating method with methoxytrimethylsilane (MTMS), both the interior and exterior of the whole rubber aerogel surface can be well coated, and the coated aerogel exhibits a super-hydrophobicity with a water contact angle of up to 134.4°. The rubber aerogel exhibits excellent heat insulation properties (Kavg = 0.035 – 0.047 W/m.K), very good thermal stability up to 500 °C, and significantly-enhanced rigidity up to a Young modulus of Eavg = 458.12 kPa, much larger than that of commercial Styrofoam. The rubber aerogel shows very good durability as it springs back to its original shape after compression tests. The rubber aerogel has a noise reduction coefficient (NRC) of 0.41 and performs approximately 10% better than commercial sound foam absorber at 2000–3000 Hz. The maximum oil absorbtion capacity of the rubber aerogel in this work is 19.3 g/g, very competitive to commercial sorbents. The fabrication method can also be scaled up for several other industrial applications, not limited to sound, heat and sorbent applications.
In this work, graphene aerogel (GA)–poly (methyl methacrylate) (PMMA) composites are first developed by backfilling PMMA into the pores of the GAs, providing uniform distribution of multi-layer ...reduced graphene oxide (m-rGO) sheets in the PMMA matrix. Electrical, mechanical and thermal properties of the as-prepared GA–PMMA composites are investigated by two-probe, microindentation and comparative infrared techniques respectively. As graphene loadings increase from 0.67 to 2.50vol.%, the composites exhibit significant increases in electrical conductivity (0.160–0.859S/m), microhardness (303.6–462.5MPa) and thermal conductivity (0.35–0.70W/mK) from that of pure PMMA as well as graphene–PMMA composites prepared by traditional dispersion methods. Thermal boundary resistance between graphene and PMMA is estimated to be 1.906×10−8m2K/W by an off-lattice Monte Carlo algorithm that takes into account the complex morphology, size distribution and dispersion of m-rGO sheets.
•For the first time, paper waste can be converted into a green cellulose aerogel.•The material has high water/oil absorption capacities of 18–20 times of its weight.•Up to 99.8% of the liquid is ...recovered simply by squeezing the aerogel.•The material shows low thermal conductivities of 0.029–0.032 Wm−1K−1.•The aerogel shows good flexibility and mechanical property.
A cost effective and scalable recipe for fabricating biodegradable cellulose aerogels from paper waste has been realized. The green aerogel is macroporous and has extremely low density and thermal conductivity: 0.04gcm−3 and 0.029–0.032Wm−1K−1, respectively. It is highly absorbent, absorbing 18–20 times its weight in liquid. Up to 99.8% of the liquid is recovered simply by squeezing the aerogel. The fabrication can be optimized for absorbing polar (water) or non-polar liquids (oil). Coating the aerogel with methyltrimethoxysilane improves its hydrophobicity without affecting its absorbency. Mechanically, the aerogel is flexible yet strong making a wide range of applications possible.
Single-atom catalysts (SACs) offer many advantages, such as atom economy and high chemoselectivity; however, their practical application in liquid-phase heterogeneous catalysis is hampered by the ...productivity bottleneck as well as catalyst leaching. Flow chemistry is a well-established method to increase the conversion rate of catalytic processes, however, SAC-catalysed flow chemistry in packed-bed type flow reactor is disadvantaged by low turnover number and poor stability. In this study, we demonstrate the use of fuel cell-type flow stacks enabled exceptionally high quantitative conversion in single atom-catalyzed reactions, as exemplified by the use of Pt SAC-on-MoS
/graphite felt catalysts incorporated in flow cell. A turnover frequency of approximately 8000 h
that corresponds to an aniline productivity of 5.8 g h
is achieved with a bench-top flow module (nominal reservoir volume of 1 cm
), with a Pt
-MoS
catalyst loading of 1.5 g (3.2 mg of Pt). X-ray absorption fine structure spectroscopy combined with density functional theory calculations provide insights into stability and reactivity of single atom Pt supported in a pyramidal fashion on MoS
. Our study highlights the quantitative conversion bottleneck in SAC-mediated fine chemicals production can be overcome using flow chemistry.
For the first time, successful fabrication of the cotton aerogels and cotton-cellulose aerogels is achieved using recycled fibers from environmental waste for oil absorption. The pure cotton and ...cotton-cellulose aerogels are obtained using a cost-effective mixing-blending method with polyamide-epichlorohydrin as strengthening additives. The obtained aerogels are silanized using methyltrimethoxysilane via a facile chemical vapor deposition to endow aerogels with hydrophobic surface. Effects of fiber concentrations and cotton-to-cellulose mass ratio on oil absorption performance in various solvents are also investigated. The cotton aerogel with an initial concentration of 0.25wt% presents the highest oil absorption capacity over 100gg−1. Besides, the cotton/cellulose aerogels also demonstrate good absorption capacity in different pollutant organics. The absorption kinetics of the aerogels with different cotton concentrations are also investigated using pseudo first-order model. Both equilibrium absorption and absorption kinetics demonstrate cotton/cellulose aerogels as promising materials for oil absorption and environmental pollution treatment.
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•Cotton aerogel with absorption capacity over 100gg−1 was prepared through simple solution routine.•Silanized cotton and cotton/cellulose aerogel present good hydrophobicity.•Cotton/cellulose aerogels show remarkable absorption capacity in various contaminates.•Cellulose helps to improve absorption reversibility for the composite aerogels.
The search for solid electrolytes with high stability and ionic conductivity is a long sought-after goal in the development of safe and high energy density Li-ion batteries. Garnet-type lithium ...conductors form a most promising family of materials due to their good chemical stability. However, the low conductivity at room temperature prevents wider application of these materials. It has long been recognized that alkaline earth metals are confined exclusively to dodecahedral 8-coordinated sites within the garnet framework. In contrast to this dominant viewpoint, we show that Ca2+ cations can occupy the octahedral 6-coordinated sites, leading to an enhanced room temperature conductivity of 5.2×10−4Scm−1 and reduced activation energy of 0.27eV, together with a 0 to 9V electrochemical stability window. This finding opens up a new opportunity for the design of ceramic electrolytes with higher conductivities, providing added impetus for further exploration of oxide electrolyte chemistry.
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•Mechanochemical doping of garnet-type solid Li-ion conductors with Ca places it at octahedral 6-coordination sites.•High ionic conductivity of 5×10−4Scm−1 and wide electrochemical stability window of 9V are obtained.•A generic strategy is identified for doping garnet structure with rare earth oxides to improve electrochemical properties.
In this article, we report the development of manganese oxide (Mn 3 O 4 ) on carbon nanotube (CNT) hydrogels as binder-free electrodes for asymmetric supercapacitors. The CNT hydrogels consisting of ...three dimensionally inter-connected nanotubes are prepared via a facile sol–gel method. Afterwards, flower-like Mn 3 O 4 is incorporated into CNT hydrogels using a pulse electrochemical deposition. Satisfactory electrochemical performance with a high specific capacitance of 182 F g −1 (473 mF cm −2 ) is achieved. When employing activated carbon as negative electrodes, the assembled asymmetric supercapacitor exhibits a high potential window of 2 V to reach a specific energy of 26.6 W h kg −1 and a specific power of 5.2 kW kg −1 . These results are much better compared with the results from pure Mn 3 O 4 . The remarkable performance of our composites can be ascribed to a highly conducting CNT micro-scaffold and pseudocapacitive Mn 3 O 4 .
Metal-based aerogels have attracted numerous studies due to their unique physical, structural, thermal, and chemical properties. Utilizing aluminum waste, a novel, facile, environmentally friendly ...approach to aluminum-based aerogels is proposed. In this work, the aluminum-based aerogels produced do not use toxic chemicals unlike conventional aerogel production. Aluminum powder, with poly(acrylic acid) and carboxymethyl cellulose as binders, is converted into aluminum-based aerogels using the freeze-drying method. The aluminum-based aerogels have low density (0.08-0.12 g/cm
) and high porosity (93.83-95.68%). The thermal conductivity of the aerogels obtained is very low (0.038-0.045 W/m·K), comparable to other types of aerogels and commercial heat insulation materials. Additionally, the aerogels can withstand temperatures up to 1000 °C with less than 40% decomposition. The aerogels exhibited promising oil absorption properties with their absorption capacity of 9.8 g/g and 0.784 g/cm
. The Young's modulus of the aerogels ranged from 70.6 kPa to 330.2 kPa. This study suggests that aluminum-based aerogels have potential in thermal insulation and oil absorption applications.
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