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![a Hierarchical structure of cellulose from meters to nanometers. b The reaction between cellulose and strong acid to obtain CNC. c Structure of CNF. d BC in bacterial culture. e The classification and preparation of cellulose derivatives [34]](publication/353859622/figure/fig3/AS:1118531601076236@1643690123910/a-Hierarchical-structure-of-cellulose-from-meters-to-nanometers-b-The-reaction-between.png)
a Hierarchical structure of cellulose from meters to nanometers. b The reaction between cellulose and strong acid to obtain CNC. c Structure of CNF. d BC in bacterial culture. e The classification and preparation of cellulose derivatives [34]
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![Structural changes of zinc oxide nanogenerators [6]. a Experimental...](publication/353859622/figure/fig1/AS:1118531601080325@1643690123791/Structural-changes-of-zinc-oxide-nanogenerators-6-a-Experimental-design-of_Q320.jpg)
Nanogenerators, as emerging energy generation devices, can effectively collect and utilize tiny energy in the environment. Recently, the development of cellulose based functional materials for nanogenerators has become a competing research topic. However, there are limited review literatures on cellulose-based nanogenerators. This paper presents a...
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... For example, by doping cellulose and other piezoelectric materials, electron-rich groups (hydroxyl, amino, alkoxy, etc.) and electron-poor groups (acyl, aldehyde, etc.) can be arranged side by side on both sides of the polymer chain, making the material dipole-rich. Under the same strain conditions, a larger piezoelectric field is generated, resulting in excellent piezoelectric properties [114,115]. In addition, by chemically modifying the surface of the material and doping polar fillers into the interior of the material, the affinity for electrons and the pore structure of the power generation material can be changed, thus improving the triboelectric properties [115]. ...
Natural environment hosts a considerable amount of accessible energy, comprising mechanical, thermal, and chemical potentials. Environment-induced nanogenerators are nanomaterial-based electronic chips that capture environmental energy and convert it into electricity in an environmentally friendly way. Polymers, characterized by their superior flexibility, lightweight, and ease of processing, are considered viable materials. In this paper, a thorough review and comparison of various polymer-based nanogenerators were provided, focusing on their power generation principles, key materials, power density and stability, and performance modulation methods. The latest developed nanogenerators mainly include triboelectric nanogenerators (TriboENG), piezoelectric nanogenerators (PENG), thermoelectric nanogenerators (ThermoENG), osmotic power nanogenerator (OPNG), and moist-electric generators (MENG). Potential practical applications of polymer-based nanogenerator were also summarized. The review found that polymer nanogenerators can harness a variety of energy sources, with the basic power generation mechanism centered on displacement/conduction currents induced by dipole/ion polarization, due to the non-uniform distribution of physical fields within the polymers. The performance enhancement should mainly start from strengthening the ion mobility and positive/negative ion separation in polymer materials. The development of ionic hydrogel and hydrogel matrix composites is promising for future nanogenerators and can also enable multi-energy collaborative power generation. In addition, enhancing the uneven distribution of temperature, concentration, and pressure induced by surrounding environment within polymer materials can also effectively improve output performance. Finally, the challenges faced by polymer-based nanogenerators and directions for future development were prospected.
... [143] In a series of collaborative works, the chemically modified CNF surface also achieved TENG stabilization in dynamic cycling, remarkable performance improvement in current and voltage compared with unfunctionalized nanocellulose film-based nanogenerators -could be obtained (Figure 7e), which the smart mobile pouch TENG achieved the electrical energy harvesting from lateral sliding, vertical contact and separation with worn fabric. [144] On the basis of the altered design, the modification of cellulose can improve the electrical properties, thus allowing significant enhancement of the output performance of TENG. ...
Nanocomposite represents the backbone of many industrial fabrication applications and exerts a substantial social impact. Among these composites, metal nanostructures are often employed as the active constituents, thanks to their various chemical and physical properties, which offer the ability to tune the application scenarios in thermal management, energy storage, and biostable materials, respectively. Nanocellulose, as an emerging polymer substrate, possesses unique properties of abundance, mechanical flexibility, environmental friendliness, and biocompatibility. Based on the combination of flexible nanocellulose with specific metal fillers, the essential parameters involving mechanical strength, flexibility, anisotropic thermal resistance, and conductivity can be enhanced. Nowadays, the approach has found extensive applications in thermal management, energy storage, biostable electronic materials, and piezoelectric devices. Therefore, it is essential to thoroughly correlate cellulose nanocomposites’ properties with different metallic fillers. This review summarizes the extraction of nanocellulose and preparation of metal modified cellulose nanocomposites, including their wide and particular applications in modern advanced devices. Moreover, we also discuss the challenges in the synthesis, the emerging designs, and unique structures, promising directions for future research. We wish this review can give a valuable overview of the unique combination and inspire the research directions of the multifunctional nanocomposites using proper cellulose and metallic fillers.
... This idea is very helpful in selection of dielectric layer for TENG [18]. Moreover, Zhang et al. proposed a new strategy to combat the environmental pollution by using cellulose instead of traditional polymers and utilized it to design nanogenerators [19]. Additionally, Ghafari et al. developed PVDF nanogenerator for harvesting low range frequencies and converting them into electricity [20]. ...
... Figure 5(a) demonstrates the XRD pattern of pure PVDF thin film and PBi thin films. For pure PVDF thin film, the characteristic peaks are observed at 2θ = 17.6° (100), 18.3° (020), 19.9° (021), and 26.6° ((201), (310)) confirming the existence of non-polar α-crystalline phase. ...
With the increasing demand of environmental friendly and unlimited power supplies, the use of triboelectric nanogenerator (TENG) also increases due to its high mechanical energy to electrical energy conversion ability. Herein, an arch shaped, self-powered, and wearable piezoelectric thin film with bismuth selenide based triboelectric nanogenerator, named as PBTNG, is fabricated with the help of nanoporous bismuth selenide (Bi2Se3) incorporated poly(vinyldene fluoride) (PVDF) composite piezoelectric thin film (PBi). The mechanism of the PBTNG device is induced by piezo-tribo coupling effect. Furthermore, the surface area and distribution of pore size of Bi2Se3 have been measured from Brunnauer–Emmett–Teller (BET) analysis and also described by basal spacing, which helps in increment of β-crystalline phase of the thin film. The density functional theory (DFT) has been performed to find out the electrical band gap and density of states of Bi2Se3 nanoparticles. The interaction of nanoparticle with PVDF monomer and electrical properties of β-phase has been investigated with DFT calculations as well. The fabricated triboelectric device exhibits outstanding output performance with a maximum power density of 2.03 Wm⁻² under continuous finger impartation and can illuminate light-emitting diodes (LEDs) under heel pressing and periodic finger tapping. Additionally, the wearable PBTNG device traps the biomechanical energy from different body movements like heel pressing, feet tapping, blood flow, single finger tapping, etc., and converts them into electrical energy easily. Furthermore, single electrode bismuth selenide based triboelectric nanogenerator, named as SBTNG exhibits high sensitivity value (20.2 V/kPa) at low pressure region (< 0.5 kPa) which helps in electricity generation from small scale mechanical energies such as writing on the device, mouse clicking, keyboard striking, external CD drive running, etc. Thus, self-powered and wearable energy harvester can be used in daily life as a substitute of batteries.
Graphical Abstract
Excellent output performance of PBTNG has been achieved from biomechanical and small scale mechanical energy, elevated by piezo-tribo coupling effect.
... During directional freezing, the water in the hydrogel gradually turns into ice crystals and transitions from the bottom to the top [36]. As shown in Fig. 3a, pure CAs obtained by directional freezing exhibit continuous oriented pore structures [37,38], and the lightweight property of CAs are reflected from the illustration [39,40], while the addition of BNWK and hybrid filler BNWK@Al 2 O 3 did not affect the vertical skeleton structure formed by ice crystals (Fig. 3b-f). From Fig. 3b, BNWKs (marked in the red circles) are oriented along the CA wall under the extrusion of ice crystals, for which the heat conduction pathways are marked by orange lines. ...
With the continuous innovation of electronic information technology, thermal interface materials, which mainly play the role of heat dissipation in microelectronic devices, will face great challenges. In this work, the boron nitride whiskers (BNWK)@Al2O3/cellulose aerogels (CA) were obtained by electrostatic self-assembly one-dimensional BNWK and zero-dimensional nano-Al2O3 combined with directional freezing of CA. The obtained BNWK@Al2O3/CA not only has a unique vertical network structure but also exhibits exceptional compressive mechanical strength, especially when the mass ratio of BNWK/nano-Al2O3 is 1:7. The compressive strength of BNWK@Al2O3(1:7)/CA reaches 97 kPa. Based on the flexibility of the CA and the support of the rigid hybrid filler BNWK@Al2O3, the theoretical relaxation time of the composite is also as high as 25,327 s. Furthermore, the thermal conductivity of the epoxy-based composite (BNWK@Al2O3/CA/EP) with a filler loading of 8.6 wt% is about 1.92 W/(m·K), which is 9.6 times that of pure EP; the excellent thermally conductive property is due to the accelerated phonon transport by the vertically arranged BNWK@Al2O3 network structure. Hence, this work provides a new idea for developing a new generation of thermal interface materials.
The obtained BNWK@Al2O3/CA not only has a unique vertical thermal conduction network structure, but also exhibits exceptional compressive mechanical strength.
... Lignocellulosic biomass, comprising cellulose, hemicellulose, and lignin, stands as a vitally important renewable carbon resource and a significant alternative to fossil resources [23,24]. Currently, the versatile applications of cellulose and hemicellulose, such as functional paper [25,26], gel materials [27][28][29], and energy storage [30][31][32][33], have been explored sufficiently due to their relatively simple structures and excellent biocompatibility. However, lignin, as the most abundant aromatic compound on earth, is currently underused as low-value fuel, and its potential has not been fully exploited [34,35]. ...
Peroxymonosulfate (PMS)-assisted visible photocatalytic degradation of organic pollutants via graphitic carbon nitride (g-C3N4) is a promising and environmentally friendly technology. But pristine g-C3N4 still suffers from limited visible light utilization and low charge carrier mobility. Herein, g-C3N4 doped by C derived from lignin (LCN) was synthesized via a straightforward calcination process involving a physical blend of lignin and melamine, and its photocatalysis and PMS-assisted photocatalysis under visible light for typical organic pollutant tetracycline hydrochloride (TC) were studied. The experimental results show that due to the incorporation of C atoms by replacing bridging N atoms in g-C3N4, LCN has improved visible light utilization and enhanced charge transfer. Under the assistance of PMS, LCN-1 (1 wt% lignin in g-C3N4) exhibits a markedly high TC degradation efficiency, with a degradation rate 6.74 times that of pristine g-C3N4. In addition, the main radicals and reaction mechanisms in both systems were proposed through free radical quenching experiments and electron paramagnetic resonance signal. This work offers insights into the development of low-cost C-doped g-C3N4, using sustainably sourced lignin, and further demonstrates its superior efficiency in photocatalytic degradation of TC coupled with PMS activation.
... Supercapacitor is a kind of high-power and high-performance energy storage device, and its electrochemical performance is mainly determined by the electrode materials [10][11][12][13][14][15]. As a competitive candidate of supercapacitor electrode material, biomass-based material has the advantages of controllable pore size, good electrical conductivity, large specific surface area, and easy preparation [16][17][18][19][20][21][22][23][24][25][26]. Many researches have shown that the electrolyte could be difficult to enter the micropores of carbon materials due to the rapid increase in mass transfer resistance at high current densities, resulting in the poor rate performance of carbon materials [27]. ...
Supercapacitor is an important energy storage device with rapid charge/discharge, long cycle life, and high-power density. The macron vertical channel structure in wood can provide an effective buffer space for the transport and storage of electrolyte ions. The transport kinetics of the electrolyte with wood-derived carbon electrode has an important effect on its capacitance performance. Herein, the wood branch of cedar is employed to construct supercapacitor electrode with high-rate performance by facile carbonization and KOH activation. The cedar demonstrates arranged pore structure and high specific surface area. The special pore structure is retained after carbonization. Furthermore, the carbonization temperature and carbonization process are explored. As the optimized, the wood-derived porous carbon electrode displays high specific capacitance of 108 F/g at a higher current rate of 15 A/g, implying its good rate capability. Moreover, after compounding MnO2, the specific capacitance of composite electrode delivers 162.4 F/g at 0.5 A/g. The assembled symmetric supercapacitor shows high energy density of 3.01 Wh/kg at the power density of 250 W/kg. This work offers an idea for developing clean and efficient new energy technologies with high-rate performance.
... During directional-freezing, the water in the hydrogel gradually turns into ice crystals and transitions from the bottom to the top [36]. As shown in Fig. 3a, pure CAs obtained by directional freezing exhibit continuous oriented pore structures [37,38], and the light-weight property of CAs are re ected from the illustration [39,40]. While the addition of BNWK and hybrid ller BNWK@Al 2 O 3 did not affect the vertical skeleton structure formed by ice crystals (Fig. 3b-f). ...
With the continuous innovation of electronic information technology, thermal interface materials, which mainly play the role of heat dissipation in microelectronic devices, will face great challenges. In this work, the boron nitride whiskers (BNWK)@Al 2 O 3 /cellulose aerogels (CA) obtained by electrostatic self-assembly one-dimensional BNWK and zero-dimensional nano-Al 2 O 3 combined with directional freezing of CA. The obtained BNWK@Al 2 O 3 /CA not only has a unique vertical network structure, but also exhibits exceptional compressive mechanical strength, especially when the mass ratio of BNWK/nano-Al 2 O 3 is 1:7, the compressive strength of BNWK@Al 2 O 3 (1:7)/CA reaches 97 kPa, based on the flexibility of the CA and the support of the rigid hybrid filler BNWK@Al 2 O 3 , the theoretical relaxation time of the composite is also as high as 25327 s. Furthermore, the thermal conductivity of the epoxy-based composite (BNWK@Al 2 O 3 /CA/EP) with a filler loading of 8.6 wt% is about 1.92 W/(m·K), which is 9.6 times that of pure EP, the excellent thermally conductive property is due to the accelerated phonon transport by the vertically arranged BNWK@Al 2 O 3 network structure. Hence, this work provides a new idea for developing a new generation of thermal interface materials.
... Nanocellulose (NC) is a mesoscopic material formed in the regeneration process of cellulose. NC including cellulose nanocrystals (CNCs) and cellulose nanofibrils (CNFs) has been widely used in the field of functional materials due to their unique morphology of nanostructures and many featuring advantages, like excellent mechanical properties, biodegradability, and environmental friendliness [13,14]. For example, CNFs prepared by TEMPO (2, 2, 6, 6-Tetramethylpiperidine-1-oxyl) mediated oxidized has plenty of hydroxyl groups and carboxyl groups on its surface, endowing CNFs with good stability and dispersibility without aggregation in water, and making it easy to combine with other polymers or nanoparticles to construct novel reinforced composite materials and hydrogels [15,16]. ...
... In general, cells encapsulated in three-dimensional are isotropic. However, many biological tissues, such as skeletal muscle, tendons, ligaments, and cardiac tissue, have an anisotropic cell 14 arrangement. Furthermore, some physiological functions also require a cellular anisotropy, like uniaxial muscle contraction requires coaxial alignment of muscle fibers. ...
Hydrogels prepared from natural polymer have attracted extensive attentions in biomedical fields such as drug delivery, wound healing, and regenerative medicine due to their good biocompatibility, degradability and flexibility. This review outlines the commonly used natural polymer in hydrogel preparation, including cellulose, chitosan, collagen/gelatin, alginate, hyaluronic acid and starch. The polymeric structure and process/synthesis of natural polymers are illustrated, and natural polymer-based hydrogels including the hydrogel formation and properties are elaborated. Subsequently, the biomedical application of hydrogels based on natural polymer in drug delivery, tissue regeneration, wound healing and other biomedical field is summarized. Finally, the future perspectives of natural polymers and hydrogels based on them are discussed. For natural polymer, novel technologies such as enzymatic and biological methods are developed to improve the structural properties and the development of new natural based polymers or natural polymer derivatives with high performance is still very important and challenging. For natural polymer-based hydrogels, novel hydrogel materials, like double-network hydrogel, multifunctional composite hydrogels and hydrogel microrobots are designed to meet the advanced requirements in biomedical application, and new strategies such as dual-crosslinking, microfluidic chip, micropatterning and 3D/4D bioprinting, have been explored to fabricate advanced hydrogel materials with designed properties for biomedical application. Overall, natural polymeric hydrogels have attracted increasing interests in biomedical application, and the development of novel natural polymer-based materials and new strategies/methods for hydrogel fabrication is badly desirable and still challenging.
... Among them, cellulose nanomaterials, for instance, cellulose nanofibers (CNFs), derived from cellulose, have attracted much attention for a wide range of applications including but not limited to those related to Pickering emulsions because of their high specific surface area, easy modification, and good biocompatibility, just to name a few [45][46][47]. In our previous work, FeCl 3 -catalyzed formic acid hydrolysis combined with high-pressure homogenization to produce CNFs from industrial kraft pulp was reported [48]. ...
... The FTIR spectra of the CNFs, PW, MF, and PCM microcapsules are shown in of ester groups, which is because the fact that FA could react with cellulose through esterification [45,53]. MF displays vibration at 3410, 1300-1500, 996, and 810 cm −1 , which are attributed to the N-H stretching vibrations of a secondary amine, the methylene C-H bending vibration, the C-H out of plane deformations, and bending vibration of triazine ring, respectively [42]. ...
Phase change materials (PCMs) possess remarkable capability to store and release substantial amounts of energy during the processes of melting and crystallization across a wide temperature range, thus holding great promise in applications related to temperature regulation and thermal energy storage. Herein, to effectively address PCM leakage and enhance thermal conduction, PCM microcapsules with melamine–formaldehyde resin (MF) shell were prepared using in situ polymerization of Pickering emulsions stabilized by cellulose nanofibrils (CNFs). CNFs were selected as the stabilizers for the Pickering emulsions and as reinforcing nanofillers for the MF shell, owing to their excellent emulsifying capability, high mechanical strength, and sustainable nature. Paraffin wax (PW) was utilized as the PCM material. The resulting PCM microcapsules with MF resin shells and PW core had a diameter ranging from 2 to 4 µm. Results showed that microcapsule with the core–shell ratio of 2 (Micro-2.0) exhibited the highest latent heat of crystallization and latent heat of fusion, measuring approximately 128.40 J/g and 120.23 J/g, respectively. The encapsulation efficiency of Micro-2.0 was determined to be approximately 79.84%.
... The current common water purification methods, including UV irradiation, chlorination, and ozone oxidation, still have limitations, such as low oxidation capacity, high energy consumption, and secondary pollution [7][8][9]. To this end, researchers constantly develop a variety of water purification methods [10-13. ...
Antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) have become hot topics in the field of water purification. In this paper, graphite carbon nitride (g-C3N4) and black phosphorus quantum dots (BPQDs) were used as raw materials to fabricate a non-metallic heterojunction composite photocatalyst (H-g-C3N4/BPQDs) by hydrothermal impregnation, high-temperature calcination, and ice-assisted ultrasound. The H-g-C3N4/BPQDs was used to remove antibiotics and biological pollution from water under visible light irradiation. Based on the porous structure and high specific surface area of H-g-C3N4, the obtained type II heterojunction structure promoted the absorption of visible light, accelerated the interfacial charge transfer, and inhibited the recombination of photogenerated electron–hole pairs. Under visible light irradiation, the degrading efficiency of TC by H-g-C3N4 /BPQDs exceeded 91% in 30 min, and E. coli K12 M1655 can be completely inactivated in 4 h. In addition, the maximum inactivation rate of H-g-C3N4 /BPQDs for E. coli HB101(RP4) was 99.99% in 4 h, and the degradation efficiency of RP4 was more than 85%. This study provides not only a new idea for the design of green g-C3N4-based non-metallic heterojunction photocatalysts but also a broad prospect for the application of g-C3N4-based photocatalysts for the removal of ARGs in water treatment.
