Biomass-derived Carbon Aerogels Research Articles

Sodium alginate derived SiC-carbon composite aerogel for effective microwave absorption

Biomass-derived carbon aerogels are expected to be ideal candidates for electromagnetic wave (EMW) absorption due to their extensive sources, cheap cost, low density and abundant porosity. Herein, using the natural polymer sodium alginate (SA) as the carbon-based precursor and SiC nano-whiskers (SiCw) as the reinforcing material, a series of three-dimensional (3D) SiCw@C composite aerogels doped with different metal ions (Fe, Ni, Al) were designed and studied for lightweight and effective EMW absorption. The emergence of metal ions and three-dimensional conductive carbon networks enriches the loss mechanism of the composites. The results show that the SiCw@C-Al exhibits a considerable minimum reflection loss (RLmin) value at 1.5 mm thickness (-28.7 dB) and a broad effective absorption bandwidth (EAB, RL < -10 dB) of 4.1 GHz. Meanwhile, SiCw@C-Fe has good wave absorption performance at a thickness of 2 mm, RLmin is −49.2 dB, and EAB is 3.6 GHz. By adjusting the matching thickness of the Al3+ and Fe3+ crosslinked composite aerogel from 1.5 mm to 3.5 mm, the integrated EAB can cover the Ku-band, X-band and even C-band. The SA derived 3D SiCw@C composite aerogels open a new path for the design of lightweight and effective EMW absorption materials used in multi-frequency.

Ti3C2TX/carbon aerogels derived from winter melon for high-efficiency photothermal conversion

Solar-driven interfacial evaporation is a promising and cost-effective technique for converting light to heat, especially for seawater desalination to address the scarcity of fresh water resources. Biomass-based carbon aerogels have demonstrated significant potential for photothermal conversion due to their low cost, renewability, and environmental friendliness. However, there is still room for improvement in enhancing the photothermal conversion performance of biomass-derived carbon aerogels. In this study, we present Ti3C2TX/carbon aerogels derived from winter melon, which exhibit exceptional photothermal conversion properties for solar steam generation. The Ti3C2TX/carbon aerogels were prepared using a combined process involving hydrothermal treatment, carbonization, and dip-coating, with winter melon as the raw material. The synergistic effect of MXene and carbon aerogels contributes to the satisfactory photothermal conversion performance of the Ti3C2TX/carbon aerogels, including a high evaporation rate (up to 1.48 kg m−2 h−1 under 1 sun irradiation), a high photothermal conversion efficiency (92.3 %), and excellent cycling stability. Moreover, the photothermal properties of the Ti3C2TX/carbon aerogels improve with an increasing mass of Ti3C2TX loading in the aerogel. In addition to solar steam generation, the Ti3C2TX/carbon aerogels also exhibit great potential in applications such as photothermal therapy, deicing, and oil absorption, owing to their exceptional photothermal properties.

Biomass-derived porous carbon aerogels for effective solar thermal energy storage and atmospheric water harvesting

Solar-powered hydrated salt-based phase change materials have great potential in the field of solar building energy efficiency. However, hydrated salts suffer from leakage, subcooling and phase separation in practical applications. To address these problems, this study proposes a solution to encapsulate hydrated salt with biomass-derived carbon aerogel as a carrier, which can effectively mitigate the leakage, subcooling, and phase separation problems of hydrated salt without the need of additional modifiers. The composite phase change material exhibited high phase change enthalpy retention (92%), negligible supercooling (0.4 °C), and excellent photothermal conversion efficiency (91.5%). In addition, thanks to the rich porosity and superhydrophilicity of the carbon aerogel, a composite hygroscopic agent combined with lithium chloride was prepared for high-performance atmospheric water harvesting. The composite hygroscopic material has a moisture adsorption capacity of 2.1 g g−1 at 90% RH and can desorb more than 92.3% of the moisture by solar energy drive. The performance was stable after several adsorption-desorption cycles. The multifunctional composites based on biomass-derived carbon aerogels have excellent performance in solar thermal storage and atmospheric water harvesting, providing a new perspective on solar thermal utilization.

Biomass-Derived Carbon Aerogels for ORR/OER Bifunctional Oxygen Electrodes.

The oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) are crucial electrochemical reactions that play vital roles in energy conversion and storage technologies, such as fuel cells and metal-air batteries. Typically, noble-metal-based catalysts are required to enhance the sluggish kinetics of the ORR and OER, but their high costs restrict their practical commercial applications. Thus, highly active and strong non-noble metal catalysts are essential to address the cost and durability challenge. Based on previous research, carbon-based catalysts may present the best alternatives to these precious metals in the future owing to their affordability, very large surface areas, and superior mechanical and electrical qualities. In particular, carbon aerogels prepared using biomass as the precursors are referred to as biomass-derived carbon aerogels. They have sparked broad attention and demonstrated remarkable performance in the energy conversion and storage sectors as they are ecologically beneficial, affordable, and have an abundance of precursors. Therefore, this review focuses on various nanostructured materials based on biomass-derived carbon aerogels as ORR/OER catalysts, including metal atoms, metal compounds, and alloys.

Bioinspired self-assembled Fe/Cu-phenolic building blocks of hierarchical porous biomass-derived carbon aerogels for enhanced electrocatalytic oxygen reduction

Biomass-derived metal/carbon hybrid functional materials are considered to be highly promising electrocatalysts for oxygen reduction reactions (ORR). This is because of the desirable properties that they offer, including their complex microarchitectures，low costs，and feasibility of large scale production. In this work, we report a bottom-up synthesis of an economical, highly-active, and stable ORR electrocatalyst -- Fe/Cu-phenolic supramolecule decorated hierarchical porous biomass-derived N-self-doped carbon aerogel. With our method of thermal carbonization of bimetallic polyphenol networks functionalized collagen/cellulose nanocrystals (Col/CNCs), this material is shown to have a large number of storage sites and enhanced diffusion kinetics for optimal electrocatalytic oxygen reduction. Thanks to the rich active functional groups of Col/CNCs, along with the interfacial adhesion ability of plant polyphenols, we successfully synthesized a group of carbon aerogel composites loaded with metal nanoparticles. Benefiting from the fractal structure of the natural building blocks, the as-synthesized FexCuy/CCol-CNCA presents a hierarchical porous structure, exquisite aerogel morphology and a heteroatom composition. With these advantages, it is demonstrated to have higher durability and better electrocatalytic ORR performance than the commercial 20% Pt/C.

Biomass-derived carbon aerogel for peroxymonosulfate activation to remove tetracycline: Carbonization temperature, oxygen-containing functional group content, and defect degree

A biomass-derived carbon aerogel (CA) was prepared and employed as an efficient metal-free and green carbon-based catalyst for peroxymonosulfate (PMS) activation to degrade tetracycline (TC). The surface functional groups, morphology, and other properties of the CA were characterized using various methods. Different carbonization temperatures were used to produce CA samples to control the oxygen-containing functional group content and defect degree, both of which play important roles in PMS activation. The carbonization temperature showed a clear negative correlation with the oxygen-containing functional group content on the CA surface, while exhibiting a positive correlation with the degree of defects in the CA. The optimal temperature for producing the CA was 300 ℃ owing to the high oxygen-containing functional group content and low loss rate. Neutral and weakly alkaline conditions were conducive to TC removal. Under optimal conditions, 93% removal of TC could be achieved within 90 min. The results of reactive oxygen species (ROS) quenching experiments and electron paramagnetic resonance (EPR) spectroscopy indicated that both non-radical species (1O2 and electrons) and radical species (•OH and SO4•−) resulted in the removal of TC. 1O2 was identified as the main activated ROS. This study deepens our understanding of the preparation of biomass-derived carbon aerogels and control of the oxygen-containing functional group content and defect degree for improving the pollutant removal efficiency.

Facile heteroatom doping of biomass-derived carbon aerogels with hierarchically porous architecture and hybrid conductive network: Towards high electromagnetic interference shielding effectiveness and high absorption coefficient

In order to eliminate the secondary electromagnetic pollution, it is imperative to develop high-performance electromagnetic shielding materials with high-efficiency absorption coefficient. However, it remains a formidable challenge to simultaneously achieve high EMI shielding effectiveness (SE) and high absorption coefficient. Herein, a facile and environmentally strategy was proposed to fabricate heteroatom-doped carbon aerogels via graphene oxide nanosheet (GONS)/cellulose composite hydrogels as precursors for absorbing organic dyes, followed by freeze-drying and a specific two-stage carbonization process. The biomass-derived carbon aerogels possessed hierarchically porous architecture and heterogeneous conductive network with great conductivity difference. Consequently, the heteroatom-doped GNS-based carbon aerogels exhibited an outstanding EMI SE of 97.3 dB in the X band and high absorption coefficient of 0.69 at a density of as low as 68.9 mg/cm3. The highly efficient EMI shielding performance originated from the multiple shielding mechanisms involving multiple reflection, interfacial polarization, conduction loss and dipole polarization, which could effectively absorb and dissipate the incident EMWs as heat energy. The ingenious structural design puts forward a promising approach to conquering the contradiction between high EMI SE and high absorption coefficient, and the carbon aerogels have great potential or value in the applications of aircraft and spacecraft as lightweight shielding materials.

Biomass-derived, multifunctional and wave-layered carbon aerogels toward wearable pressure sensors, supercapacitors and triboelectric nanogenerators

Nowadays, great effort has been devoted to designing carbon aerogels with compressibility, elasticity, wide linear sensitivity and multifunctional characteristics. Herein, a biomass-mediated strategy was applied to synthesize nitrogen doped carbon aerogels (C-NGD) by using the calcinated mixture of glucose & dicyandiamide nanosheets (C-GD) and cellulose nanofibers (CNFs) as sustainable, cheap and massive precursors. The synthesized C-NGD has considerable elasticity, compressibility and fatigue resistance. The interaction between C-GD and CNFs leads to a super stable wave-layered structure that can support an ultrahigh compression strain (95%) and long-term compression (3000 cycles, at a 50% strain). Particularly, a wide-range linear sensitivity can be obtained under 0–10 kPa, with a high sensitivity of 10.08 kPa−1. These advantages enable the carbon aerogel to be applied in wearable piezoresistive sensing devices to detect body motion and biosignals. Besides, C-NGD also shows potential applications for supercapacitors and triboelectric nanogenerators. Thus, this biomass-derived carbon aerogel is a kind of multifunctional material toward flexible electronics, and energy conversion/storage devices.

Bio-Inspired Biomass-Derived Carbon Aerogels with Superior Mechanical Property for Oil–Water Separation

It is a challenge to fabricate three-dimensional carbon aerogels based on natural renewable resources with stability, flexibility, and versatility. Here, an ultralight, elastic, and hydrophobic mul...

Structuring Hierarchically Porous Architecture in Biomass-Derived Carbon Aerogels for Simultaneously Achieving High Electromagnetic Interference Shielding Effectiveness and High Absorption Coefficient.

Developing high-performance electromagnetic interference (EMI) shielding materials with high absorption coefficient is highly desired for eliminating the secondary pollution of reflected electromagnetic wave (EMW). Nevertheless, it has long been a daunting challenge to achieve high shielding effectiveness (SE) and ultralow or no reflection SE simultaneously. Herein, highly porous and conductive carbon nanotube (CNT)-based carbon aerogel with a meticulously designed hierarchically porous structure from micro and sub-micro to nano levels is developed by specific two-stage pyrolysis and potassium hydroxide activation processes. The resultant activated cellulose-derived carbon aerogels (a-CCAs) exhibit an ultrahigh EMI SE of 96.4 dB in the frequency range of 8.2-12.4 GHz in conjunction with an exceptionally high absorption coefficient of 0.79 at a low density of 30.5 mg cm-3. The successful construction of hierarchically porous structure is responsible for the excellent "structurally absorbing" ability of a-CCAs, and the introduction of CNT-based heterogeneous conductive network can effectively dissipate the incident EMWs by interfacial polarization and microcurrent losses. Moreover, the as-prepared a-CCAs have a water contact angle of as high as 158.3°and a sliding angle of as low as 5.3°, revealing their superhydrophobic feature. The ingenious structure design proposed here provides a possible pathway to overcome the conflict between high EMI shielding performance and ultralow or no secondary reflection, and the as-prepared a-CCAs are exceedingly promising in the application of telecommunication, microelectronics, and spacecraft.

Structuring dense three-dimensional sheet-like skeleton networks in biomass-derived carbon aerogels for efficient electromagnetic interference shielding

Developing ultralight, highly conductive carbon aerogels with facilely tunable microscopic structure is still a long-standing issue to effectively shield the electromagnetic interference (EMI). Here, highly porous and conductive all biomass-derived carbon aerogels were first successfully achieved by carbonizing cellulose aerogels, which held excellent structure designability by controlling cellulose content in lithium hydroxide/urea aqueous solution, porogen composition in solvent exchange process, as well as freezing rate during freeze-drying. The as-prepared cellulose-derived carbon aerogels with optimized structure of small pore size and dense three-dimensional sheet-like skeleton network were demonstrated to be highly efficient to greatly prolong the propagation path of electromagnetic waves (EMWs) and dissipate incident EMWs into heat energy, exhibiting the dominant EMI shielding mechanism of EMW absorption. As a result, an impressive EMI shielding effectiveness of as high as 93.1 dB in the X band frequency range at a density of as low as 0.079 g cm−3 was achieved. Of more practical significance is that the new insight into the relationship between microscopic pore structure of carbon aerogels and their EMI shielding performance provides a valuable clue in developing highly efficient EMI shielding carbon aerogels in the application of microelectronics, aircraft and spacecraft.

A Chemical Blowing Strategy to Fabricate Biomass-Derived Carbon-Aerogels with Graphene-Like Nanosheet Structures for High-Performance Supercapacitors.

The efficient exploitation and utilization of low-cost and biomass-derived carbon materials will play an active role in developing sustainable energy storage systems. However, the difficult morphology control and incomplete activation limits their pervasive application in electrochemical energy storage. Inspired by the famous Chinese folk handicraft of sugar-figure blowing, biomass-derived carbon aerogels (GCA) with 2 D graphene-like thin nanosheets were fabricated by a simple chemical blowing strategy from a viscous agaric solution obtained through hydrothermal treatment of agaric. A chemical blowing agent (NH4 Cl) was used to effectively exfoliate the bulk biomass-derived carbon flake into 2 D graphene-like nanosheets, which resulted in a highly porous structure and high specific area (2200 m2 g-1 ) after the activation process. As a result, a high specific capacitance of 340 F g-1 at 3 A g-1 and a high specific energy of 25.5 Wh kg-1 at a power density of 2 kW kg-1 was obtained for the GCA electrode, which can be attributed to the abundant electrochemically active surfaces, short ion transport paths, and effective electrolyte infiltration.. This work demonstrates an effective and low-cost strategy to prepare hierarchical and well-organized porous biomass carbon materials with graphene-like nanosheets for high-performance supercapacitors.

Single iron atoms stabilized by microporous defects of biomass-derived carbon aerogels as high-performance cathode electrocatalysts for aluminum–air batteries

Biomass-derived carbon aerogel with hierarchical porosity and FeN4 single atom sites outperforms platinum towards the oxygen reduction reaction in alkaline media and can be used as the cathode catalyst for aluminium–air batteries.

Multifunctional carbon aerogels from typha orientalis for oil/water separation and simultaneous removal of oil-soluble pollutants

Biomass-derived carbon aerogels with 3D network porous structure show excellent physical properties and exhibit superior application potential. Here, we prepare multifunctional carbon aerogels (MCAs) by carbonization of aerogels composed of typha orientalis fibers. The MCAs feature light mass (5.0 mg cm−3), excellent compressibility (80%), good electrical conductivity (0.18 S cm−1), and very high oil absorption capacity (42–160 g g−1). Because of the excellent superhydrophobic/superoleophilic properties, the MCAs can be used as adsorbent materials to remove free oils in water by various methods. The MCAs can also be applied for efficient separation of surfactant-stabilized water-in-oil emulsions and rapid removal of soluble dyes in oils. Furthermore, the mixtures of multi-emulsions and dyes can be purified with MCAs, which makes MCAs alternative materials for oil purification.

Biomass-Derived Nitrogen-Doped Carbon Aerogel Counter Electrodes for Dye Sensitized Solar Cells.

Dye sensitized solar cells have emerged as an attractive alternative to conventional solar cells due to their easy processing and the abundance and low cost of their materials. However, the counter electrode in these cells employs platinum which significantly impacts their cost. Here, we report biomass-derived, nitrogen-doped carbon aerogel as an effective alternative to conventional platinum-based counter electrodes for dye sensitized solar cells. A stable suspension of biomass-derived, nitrogen-doped carbon aerogel was prepared in DMF by using oleylamine as a binder. The nitrogen-doped carbon aerogel electrode was annealed at different temperatures, and its impact on photovoltaic performance is investigated. I-V measurements confirm that the annealing temperature substantially enhances the photovoltaic parameters of these devices; these enhancements are linked to the removal of the organic binders. Electrochemical impedance spectra of the counter electrodes confirm that removal of oleylamine in nitrogen-doped carbon aerogels reduces the series resistance of the resulting electrodes. The power conversion efficiency of the solar cells from optimized nitrogen-doped carbon aerogel exhibited comparable efficiency to that of a cell fabricated using a platinum-based counter electrode. This study demonstrates the potential of biomass-derived carbon aerogels as a cheap and sustainable replacement of platinum in DSSCs.

Polypyrrole-anchored cattail biomass-derived carbon aerogels for high performance binder-free supercapacitors

In this work, biomass-derived three-dimensional carbon fiber aerogels loading polypyrrole particles were prepared by a facile and cost-effective two-step synthesis process. Firstly, carbon aerogels were prepared by pyrolysis of cellulose aerogels composed of cattail derived cellulose microfibers, then the polypyrrole anchored interconnected carbon fiber aerogels were prepared by in-situ oxidative polymerization. Binder-free supercapacitors based on the carbon aerogel/polypyrrole composites exhibit the largest areal capacitance of 419 mF cm−2 at a current density of 1 mA cm−2 with a potential range of 0.0–0.8 V in a 1 M H2SO4 electrolyte solution. In addition, the supercapacitor electrodes exhibit a capacitance retention of 86.4% after 3000 charge-discharge cycles, demonstrating the good cycling stability of the carbon aerogel/polypyrrole composites for supercapacitors. Such three-dimensional cattail biomass-based carbon aerogels with high capacitance and long-term stability have promising application prospects in energy storage devices for supercapacitors.

Fabrication of Biomass-Derived Carbon Aerogels with High Adsorption of Oils and Organic Solvents: Effect of Hydrothermal and Post-Pyrolysis Processes.

Biomass is the most plentiful and well-utilized renewable carbon resource on the earth. Direct conversion of biomass to carbon aerogel provides a promising approach to develop adsorbent materials. In the present work, the effect of presence of water during hydrothermal treatment and holding temperature during post-pyrolysis process have been investigated for the preparation of carbon aerogels (CAs) using eggplant as raw material. The results showed that the addition of water during hydrothermal treatment was advantageous for the preparation of CA samples with higher surface area and stronger hydrophobicity, resulting in superior adsorption capacities of CAs for both oil and organic solvents compared with that fabricated without the presence of water. The optimized carbon aerogel possessed higher specific surface of 249 m2·g−1 and exhibited excellent hydrophobicity with a water contact angle of 133°. The adsorption capacities of carbon aerogel for oils and organic solvents could reach 35–45 times its own weight. In addition, the adsorbed oil and organic solvents could be recovered by distillation, and the regenerated carbon aerogels samples exhibited the stable performance and outstanding reusability. Therefore, the carbon aerogel has great potential in application of oil recovery and environmental protection.