German Edition: DOI: 10.1002/ange.201802753NanomaterialsInternational Edition: DOI: 10.1002/anie.201802753

Wood-Derived Ultrathin Carbon Nanofiber AerogelsSi-Cheng Li, Bi-Cheng Hu, Yan-Wei Ding, Hai-Wei Liang,* Chao Li, Zi-You Yu, Zhen-Yu Wu,Wen-Shuai Chen, and Shu-Hong Yu*

Abstract: Carbon aerogels with 3D networks of interconnectednanometer-sized particles exhibit fascinating physical proper-ties and show great application potential. Efficient andsustainable methods are required to produce high-performancecarbon aerogels on a large scale to boost their practicalapplications. An economical and sustainable method is nowdeveloped for the synthesis of ultrathin carbon nanofiber(CNF) aerogels from the wood-based nanofibrillated cellulose(NFC) aerogels via a catalytic pyrolysis process, whichguarantees high carbon residual and well maintenance of thenanofibrous morphology during thermal decomposition of theNFC aerogels. The wood-derived CNF aerogels exhibitexcellent electrical conductivity, a large surface area, andpotential as a binder-free electrode material for supercapaci-tors. The results suggest great promise in developing newfamilies of carbon aerogels based on the controlled pyrolysis ofeconomical and sustainable nanostructured precursors.

Carbon aerogels are widely used in renewable energyconversion and environment science as a result of theiroutstanding physical properties, such as extremely lowdensity, 3D interconnected porosity, high surface area, andlow thermal conductivity.[1] Particularly, the electrons canmove quickly along the 3D carbon skeleton of carbonaerogels, while the hierarchically porous structures provideboth of high surface areas and high accessibility to suchsurface.[2] These unique structural properties enable carbonaerogels very promising performance as heterogeneouscatalyst supports, adsorbents, and electrode materials insupercapacitors and batteries.[1a,b, 3] The classical synthetic

route to carbon aerogel materials involves a sol–gel chemistryprocess with the transformation of molecular precursors intohighly cross-linked organic gels (for example, phenolicresin).[3, 4] Upon carbonization in an inert atmosphere, thehighly cross-linked organic aerogels are converted into 3Dcarbon aerogels.[5]

The emerging of two kinds of carbon nanostructures,namely carbon nanotubes (CNTs) and graphene, and theirimpressive properties motivated a rapid expansion of thisfield with focus on translating the individual properties ofCNTs and graphene building units into 3D free-standingmacroscopic assemblies.[6] Considering the harmful andexpensive precursors or complex equipment involved in thesyntheses of these CNTs and graphene aerogels, the perfor-mance-to-cost ratio of these aerogels cannot compete withconventional phenolic resin-derived carbon aerogels, inparticular for energy and environment-related applications.[3]

To this end, it would be advantageous to develop moreefficient and economical routes to fabricate new nanocarbonaerogels, preferably based on renewable resources.[1c,7] Wehave reported a templating synthesis of carbonaceous nano-fiber aerogels based on hydrothermal carbonization ofglucose with ultrathin tellurium nanowires as templates,[8]

though the synthesis of high-cost tellurium template isarguably one drawback. Furthermore, we recently demon-strated the preparation of CNFs aerogels by direct pyrolysisof freeze-dried bacterial cellulose (BC) pellicles.[8,9] Althoughpromising of the BC-derived CNFs aerogels, the use of BC formaking carbon aerogels for practical applications is challeng-ing with respect to sustainability, as BC is normally producedusing glucose and mostly used in the field of food industry.[7a]

In this regard, the nanofibrillated cellulose (NFC) pro-duced by disintegration of plant cellulose that is the mostabundantly and sustainable biopolymer on the earth would bean ideal precursor for the synthesis of CNFs aerogels.[10] Theestimated global production capacity of nanocellulose in 2013was on the order of 600 metric tonnes, and the future globalmarket potential was estimated to be 35 million metrictonnes/year.[11] Despite of great efforts made by severalgroups, it is still an urgent challenge so far to prepare uniformCNFs aerogels from wood cellulose, as the thermal decom-position of cellulose happened at high temperature lead tosignificant weight loss and serious destroy of the nanofibrousmorphology.[12] Herein, we report a catalytic pyrolysis methodfor synthesis of CNFs aerogels from wood-derived NFC. Thecarbonization catalyst p-toluenesulfonic acid (TsOH) isdoped into the Wood-NFC aerogels before pyrolysis todramatically improve the carbon residual of Wood-NFC,which results in good maintenance of the nanofibrousmorphology and 3D network structure of Wood-NFC aero-gels during the thermal decomposition process. The prepared

[*] S.-C. Li, B.-C. Hu, Dr. Y.-W. Ding, Prof. H.-W. Liang, C. Li, Dr. Z.-Y. Yu,Dr. Z.-Y. Wu, Prof. S.-H. YuDivision of Nanomaterials & Chemistry, Hefei National ResearchCenter for Physical Sciences at the Microscale, CollaborativeInnovation Center of Suzhou Nano Science and Technology,Department of Chemistry, CAS Center for Excellence in Nanoscience,Hefei Science Center of CASUniversity of Science and Technology of ChinaHefei, Anhui 230026 (P. R. China)E-mail: hwliang@ustc.edu.cn

shyu@ustc.edu.cnHomepage: http://staff.ustc.edu.cn/~ yulab/

Prof. W.-S. ChenKey laboratory of Bio-based Material Science and Technology,Ministry of Education, Northeast Forestry UniversityHarbin 150040 (P. R. China)

Supporting information (including experimental details, character-ization of the samples, SEM and TEM images, the proposed pyrolysischemistry mechanism, electrochemical measurements, and equa-tions) and the ORCID identification number(s) for the author(s) ofthis article can be found under:https://doi.org/10.1002/anie.201802753.

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carbon aerogels consisting of uniform nanofibers with anaverage diameter of only 6 nm exhibit a high electricalconductivity of 710.9 S m�1, a large surface area (553–689 m2 g�1), and promising performance as a bind-freeelectrode material for supercapacitors.

The synthesis process of the wood-derived CNFs aerogelwas illustrated in Figure 1. The first step was the preparation

of a transparent Wood-NFC dispersion in water by TEMPO-mediated oxidation of wood cellulose pulp (never-driedeucalyptus pulp) at room temperature followed with mechan-ical disintergration using a household blender (steps i and ii inFigure 1).[10a] TEM observation of the Wood-NFC indicatedthat the cellulose pulps was converted totally into individualnanofibers with a length of a few micrometers and a uniformwidth of 3–5 nm (Figure 1; Supporting Information, Fig-ure S1). The high transmittance of the Wood-NFC dispersionfurther confirmed the successful nanofibrillation of cellulosepulps (Supporting Information, Figure S2). The second stepof the synthesis was to form a stiff and transparent Wood-NFC hydrogel by treating the Wood-NFC dispersion withhydrochloric acid (step iii in Figure 1).[13] Afterwards, thewater in the Wood-NFC hydrogel is exchanged with acetonedissolved with an organic acid, that is, para-toluenesulfonicacid (TsOH) as the pyrolysis catalyst, before undergoing CO2

critical-point-drying to yield the Wood-NFC/TsOH aerogel(steps iv and v in Figure 1). The amount of TsOH catalyst wasoptimized to be 10 wt% as indicated by the thermogravim-etry (TG) analysis (Supporting Information, Figure S3). Thescanning electron microscopy (SEM) images of the Wood-NFC/TsOH aerogel revealed a highly porous 3D nanofibrousnetwork structure (Supporting Information, Figure S4). Notethat the diameter of Wood-NFC increased to ca. 10 nm in theaerogel, indicating a slight aggregation of NFC during theCO2 critical-point-drying. The specific surface area of theNFC aerogels calculated by the Brunauer–Emmett–Teller(SBET) method was 215 m2 g�1 and much higher than those of

bacterial cellulose, tunicate cellulose, or microcrystal cellu-lose aerogels.[14] The last step was the pyrolysis of the Wood-NFC/TsOH aerogels under flowing inert gas at a hightemperature in the range of 700–1000 8C to form the finalCNFs aerogels (step vi in Figure 1). We also tried another twoorganic acids (diphenylphosphinic acid and trifluorometha-nesulfonic acid) as the carbonization catalysts to enhance thecarbon residue. They were all effective as carbonizationcatalysts, although TsOH was selected as the typical case inthe current study (Supporting Information, Table S1). Theprepared wood-derived CNFs carbon aerogels are referred toas CNFs-x, where x is the pyrolysis temperature. Forcomparison, the carbon materials were also prepared bypyrolysis of pure Wood-NFC aerogels (TsOH-free).

SEM observation of the wood-derived CNFs aerogelsrevealed that the highly uniform cellulose nanofibers retainedthe nanofibrous morphology very well during the pyrolysisprocess and were converted into interconnected ultrafinecarbon nanofibers (Figure 2a), instead of agglomerating intocarbon spheres or sheets.[12a,b] The average diameter of CNFs-800 is only 6 nm, as indicated by the statistical analysis fromTEM images (Figure 2b; Supporting Information, Figures S5,S6). High-resolution TEM (HRTEM) images showed thegraphite-like turbostratic carbon structure of the CNFs(Figure 2c). The dimension of Wood-NFC aerogel shranksignificantly by 50 % after pyrolysis at 800 8C, correspondingmore than 85% shrinking of the volume. Importantly, thecarbon residual of the Wood-NFC is as high as 26.3 wt % forCNFs-800 and much higher than reported values for nano-structured cellulose,[12b, 15] which is crucial for the maintenanceof 3D nanofibrous network of Wood-NFC during pyrolysis athigh temperature. In contrast, the carbon aerogels preparedby pyrolysis of pure Wood-NFC featured with stackednanosheets structure, indicating the destruction of te nano-fibrous network during the thermal decomposition of Wood-NFC without TsOH catalyst (Supporting Information, Fig-ure S7). The high carbon residual and significant shrinking ofthe volume resulted in an increased density from 20 mgcm�3

for the Wood-NFC aerogels to about 65–122 mg cm�3 for theCNFs aerogels, depending on the pyrolysis temperature.Increasing the pyrolysis temperature could remarkablyimprove the graphitization degree as well as the electricalconductivity (Figure 2d). Particularly, the electrical conduc-tivities of CNFs-800 and CNFs-1000 were 116 and 710 S m�1,respectively, which compares favorably with most CNTs andgraphene aerogels,[2, 6a–c,16] even though our wood-derivedCNFs aerogels have relatively high density. Additionally, thewood-derived CNFs aerogels were mechanically stable andexhibited a high compressive strength (Supporting Informa-tion, Figure S8).

Nitrogen (N2) adsorption–desorption measurements werecarried out to analyze the porous characteristics of the CNFsaerogels. All samples displayed a steep increase in adsorbedvolume at a relatively low partial pressure (P/P0 = 0� 0.01)and inconspicuous hysteresis loops at higher N2 pressures(Figure 2e), suggesting the existence of abundant microporeswith few mesopores. The SBET of the CNFs aerogels are 688,689, 610, and 553 m2 g�1 for CNFs-700, CNFs-800, CNFs-900,and CNFs-1000, respectively. These values are much higher

Figure 1. Illustration of the fabrication of wood-derived CNFs aerogels.i) TEMPO oxidation of soft wood pulp. ii) Mechanical disintegration ofTEMPO-oxidized soft wood pulp for preparing Wood-NFC. iii) HCl-treatment of Wood-NFC solution (0.7 wt%) to yield mechanicallystable Wood-NFC hydrogels. iv) Solvent exchange of the Wood-NFChydrogel with acetone dissolved with TsOH. v) CO2 critical-point-dryingor freeze-drying of the Wood-NFC/TsOH hydrogels. vi) Pyrolysis of theWood-NFC/TsOH aerogels in inert gas atmosphere to yield CNFsaerogel.

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than those of CNTs aerogels[6a,b] and comparable with those ofreduced graphene aerogels.[1c,6c,7a, 16b] The pore diameterdistribution in the microporous region for the CNFs aerogelswas between 0.2 to 0.9 nm (Supporting Information, Fig-ure S9). X-ray powder diffraction (XRD) patterns of theCNFs aerogels showed two broad diffraction peaks at around238 and 448 (Supporting Information, Figure S10), corre-sponding to the (002) and (101) crystallographic planes ofgraphitic carbon. The gradually increased intensity of thediffraction peak at 448 indicated that the graphitizationdegree increased with the pyrolysis temperature. Ramanspectra of the CNFs aerogels displayed two prominent peaksat 1350 and 1580 cm�1, corresponding to D and G band,respectively (Supporting Information, Figure S11). The ID/IG

value decreased from 1.00 to 0.87 gradually when thepyrolysis temperature increased from 700 to 1000 8C, furtherconfirming the increased graphitization degree of the CNFsaerogels. X-ray photoelectron spectra (XPS) and elementalanalysis (EA) confirmed that the CNFs aerogels werecomposed of C (> 92.0 wt %), O (< 7.5 wt%), and inappreci-able H (< 1.0 wt %) and S (< 1.0 wt %; Figure 2 f; SupportingInformation, Table S2). As expected, the C contents of theCNFs aerogels slight increased with the pyrolysis temper-atures.

Besides the supercritical drying, freeze-drying that iswidely used in a range of industrial applications[17] was alsoapplicable in the fabrication of CNFs aerogels. The key pointwas to partly exchange the water in Wood-NFC hydrogel withtert-butyl alcohol (TBA) before freeze-drying.[17, 18] For thefreeze-drying process with water, the large ice crystals grewand expelled the solute to their boundaries, leading to a sheet-like aggregates (Supporting Information, Figure S7 b).[12c,19]

Differently, small-sized needle-shaped crystals were formedwhen the TBA-containing solution was frozen,[18a, 20] whichavoided the formation of sheet-like aggregate structure andfinally resulting a highly porous 3D nanofibrous network

structure. SEM and TEM observations confirmed that theTBA-freeze-dried Wood-NFC aerogels as well as the corre-sponding carbon aerogels were also composed of 3D nano-fibrous network structure (Supporting Information, Fig-ure S12a,c,d). The BET surface area of TBA-freeze-driedWood-NFC aerogels (112 m2 g�1) was much higher than thatof directly freeze-dried Wood-NFC aerogels without TBAexchange (28 m2 g�1), but lower than that of supercritical-dried aerogels (215 m2 g�1). After pyrolysis of TBA-freeze-dried Wood-NFC aerogels at 800 8C, the obtained carbonaerogels also exhibited a high surface area of 626 m2 g�1

(Supporting Information, Figure S13). Besides TBA, anothercommon solvent, acetic acid, could also be used for freeze-drying to prepare Wood-NFC and CNFs aerogels (SupportingInformation, Figure S12b).

Furthermore, to demonstrate the universality of theorganic acid-assisted pyrolysis method, another more eco-nomical and sustainable wood-derived NFC that was pro-duced in large-scale from never-dried wood pulp by a highpressure homogenizer without the use of harsh chemi-cals,[10b, 12c] was also employed as precursor successfully forpreparing CNFs aerogels (Supporting Information, Fig-ure S14).

To understand the key role of TsOH in the successfulsynthesis of CNFs aerogels from Wood-NFC, the thermaldecomposition process of Wood-NFC and Wood-NFC/TsOHcomposite aerogels was studied by TG coupled with Fouriertransform infrared spectroscopy (TG-FTIR) and TG coupledwith gas chromatography–mass spectrometry (TG-GC-MS).Three degradation stages could be recognized for both Wood-NFC and Wood-NFC/TsOH (Figure 3a). In the case ofWood-NFC, the first degradation stage was from 20 8C toaround 200 8C, corresponding to the evaporation of a smallamount of moisture and the decomposition of carboxylicgroup.[21] The main degradation stage of an interval from200 8C to 400 8C (Figure 3a,b) was related to the thermal

Figure 2. a) SEM, b) TEM, and c) HRTEM images of the CNFs-800. d) The densities and electrical conductivities and e) nitrogen adsorption–desorption isotherms of the CNFs aerogels prepared at different pyrolysis temperatures. f) Element contents of the CNFs aerogels measured byelemental analysis.

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decomposition of cellulose, accompanied by the liberatationof volatile chemicals.[22] And the last stage, occurring in thetemperature range of 400–800 8C, was correlated with thearomatization of the remaining products that were mainlycomposed of four-carbon residue.[22b] For the case of Wood-NFC/TsOH, the main decomposition stage shifted to lowertemperature between 100 to 300 8C. Additionally, the temper-ature of maximum weight loss rate decreased from 332 8Cfor pure Wood-NFC to 236 8C for Wood-NFC/TsOH compo-site.

The TG-GC-MS spectrometric analysis of the releasedspecies during the decomposition of cellulose gave the totalion current (TIC) curves in Figure 3c. The TIC curves ofWood-NFC and Wood-NFC/TsOH were characterized byintense peaks at around 236 and 332 8C, agreeing well withDTG analysis (Figure 3b). GC spectra at the TIC peaksindicated the release of different volatile compounds with thepyrolysis of Wood-NFC and Wood-NFC/TsOH at the temper-ature of maximum weight loss rate (Figure 3d). GC-MSmeasurements revealed that the released compounds ofWood-NFC were levoglucosenone (LGO), levoglucosan(LG), and 1,4:3,6-dianhydro-a-d-glucopyranose (DGP),while the volatile pyrolysis product of Wood-NFC/TsOHwas exclusively LGO (Figure 3 d). The 3D TG-FTIR spectraof Wood-NFC and Wood-NFC/TsOH exhibited the evolvingof gas products during pyrolysis, as a function of bothwavenumber and temperature (Figure 3e,f), and reflectedthe concentration variation of the gas species. Clearly, moreH2O molecules released during the pyrolysis of Wood-NFC/TsOH at a lower pyrolysis temperature, indicating that TsOHcould enhance dehydration of cellulose at a lower temper-ature and therefore affect the subsequent pyrolysis chemistry.It is well known that the intramolecular hydrogen bonds in

cellulose result in b-1,4-glucan units forming tight aggregates,preventing the dehydration reaction. Thus, the dehydration ofcellulose should proceed in the presence of strong Brønstedacid catalysts such as sulfuric acid, which can decompose boththe strong hydrogen bonds and b-1,4-glycosidic bonds.[23] Asa kind of strong organic acid with Brønsted acid sites,[24]

TsOH can therefore catalyze the dehydration reaction ofcellulose efficiently.

Based on above TG-FTIR and TG-GC-MS analyses, weproposed a catalytic pyrolysis mechanism of the Wood-NFC/TsOH composite that involved three main steps (SupportingInformation, Figure S15). Briefly, TsOH advanced the start-ing temperature of cellulose decomposition and enhanced thedehydration substantially in the first step, which resulted inless hydroxy groups left on the dehydrated cellulose that wastherefore selectively converted into LGO in the secondstep.[22b] In contrast, the pure Wood-NFC without TsOH wasthermally converted into LG with high selectivity. Impor-tantly, LGO were converted into four-carbon residue bycleavage, which formed graphite-like layer carbons by thesubsequent aromatization in the third step, while LG was themain components of the volatile tar.[22] Therefore, the highercontent of LGO we detected by TG-GC-MS confirmed theTsOH-assisted thermal transformation process from Wood-NFC to CNFs. The formation of LGO during the pyrolysis ofWood-NFC was further confirmed by the solid 13C NMRmeasurements (Supporting Information, Figure S16).

With the unique structural advantages, that is, mechan-ically stable and porous 3D nanofibrous networks, largespecific surface area, and high electrical conductivity, thewood-derived CNFs aerogels would be potentially promisingfor electrochemical applications. As a proof-of-the-concept,we demonstrated the CNFs aerogels as binder-free electrodes

Figure 3. a) TGA and b) DTG curves of Wood-NFC and Wood-NFC/TsOH aerogels. c) TIC curves of Wood-NFC and Wood-NFC/TsOH in TG-MSmeasurement. d) Gas chromatograms of the pyrolysis of Wood-NFC and Wood-NFC/TsOH aerogels. e),f) FTIR spectra of the gas products fromthe pyrolysis of Wood-NFC (e) and Wood-NFC/ TsOH (f).

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for supercapacitors. Electrochemical properties of the CNFsaerogel supercapacitors were evaluated by a two-electrodesystem in a 2.0m H2SO4 aqueous electrolyte. The cyclicvoltammetry (CV) plots of CNFs-800 aerogel supercapacitorsat different scan rates displayed nearly rectangular shapeseven at a high scan rate of 500 mVs�1 (Supporting Informa-tion, Figure S17a), indicating an electric double layer capaci-tive behavior. Furthermore, the galvanostatic charge–dis-charge curves of CNFs aerogel supercapacitors were sym-metrical and linear even at a high current density, implyinga good capacitive peculiarity and ideal charge–dischargeability (Supporting Information, Figure S17b). Particularly,the CNFs-800 aerogel electrodes possessed a specific capaci-tance of 140 Fg�1 at 0.5 Ag�1 and maintained a high capaci-tance of 90 F g�1 at 20 Ag�1, corresponding a good capaci-tance retention ratio of 64 %, although a considerable capac-itance degradation was observed when the current densityfurther increased to 100 Ag�1 (Supporting Information, Fig-ure S18). The electrochemical impedance spectra analysisverified the low charge-transfer resistance of the CNFsaerogel electrodes (Supporting Information, Figure S19).The CNFs-1000 exhibited a much lower capacitance com-pared to CNFs-800 due to its relative low specific surface area(Supporting Information, Figure S20). Note that the capaci-tance of Wood-NFC/TsOH derived CNFs is more than twiceof that of pure Wood-NFC derived CNFs (SupportingInformation, Figure S21), indicating the superiority of theTsOH-assisted pyrolysis method. The specific capacitance ofCNFs-800-TBA is similar to that of CNFs-800, showing theapplicability of the TBA-freeze drying for preparing binder-free CNFs aerogel electrodes (Supporting Information, Fig-ure S22). Moreover, the electrochemical measurements inthree-electrode system also showed the potential of CNFsaerogel for supercapacitor applications (Supporting Informa-tion, Figures S21, S23). The evaluation of cycling stabilityrevealed a highly stable electrochemical performance ofCNFs aerogel supercapacitor (Supporting Information, Fig-ure S24). Based on the Ragone plot, the maximum powerdensity of the CNFs aerogel supercapacitor was estimated tobe 48.6 kWkg�1 (Supporting Information, Figure S25), whichis superior to most reported binder-free pure carbon-basedelectrical double-layer capacitors (Supporting Information,Table S3). The capacitor performance of the CNFs aerogelscould be further improved by doped with heterogeneousatoms or metal oxides.[25]

In summary, we have developed an efficient and sustain-able method for the fabrication of mechanically stable CNFsaerogels by engineering the thermal decomposition chemistryof Wood-NFC. The wood-derived CNFs aerogels possessedan electrically conductive 3D nanofibrous network structurewith a large specific surface area and exhibited promisingpotential as a binder-free electrode materials for supercapa-citors. Benefiting from the unique structural feature, addi-tional potentials of the CNFs aerogels would include a varietyof environment- and energy-related applications, such aswater purification, electrocatalysts supports, and recharge-able batteries. The catalytically thermal conversion of inex-pensive and earth-abundant precursors into high value-addedcarbon materials described in the present work shed new light

on the future development of renewable materials by greenchemistry.

Acknowledgements

We acknowledge the funding support from the NationalNatural Science Foundation of China (Grants 21431006,21761132008, 21671184), the Foundation for InnovativeResearch Groups of the National Natural Science Foundationof China (Grant 21521001), Key Research Program ofFrontier Sciences, CAS (Grant QYZDJ-SSW-SLH036), theNational Basic Research Program of China (Grant2014CB931800), and the Users with Excellence and ScientificResearch Grant of Hefei Science Center of CAS(2015HSCUE007), H.-W.L. is thankful for the support by“the Recruitment Program of Global Experts”.

Conflict of interest

The authors declare no conflict of interest.

Keywords: carbon nanofiber aerogels ·nanofibrillated cellulose · pyrolysis chemistry · supercapacitors ·wood

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Manuscript received: March 5, 2018Revised manuscript received: April 2, 2018Accepted manuscript online: April 23, 2018Version of record online: && &&, &&&&

AngewandteChemieCommunications

6 www.angewandte.org � 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim Angew. Chem. Int. Ed. 2018, 57, 1 – 7� �

These are not the final page numbers!

Communications

Nanomaterials

S.-C. Li, B.-C. Hu, Y.-W. Ding,H.-W. Liang,* C. Li, Z.-Y. Yu, Z.-Y. Wu,W.-S. Chen, S.-H. Yu* &&&&—&&&&

Wood-Derived Ultrathin CarbonNanofiber Aerogels

Nano-woodwork : An economical andsustainable method has now been devel-oped for the synthesis of ultrathin carbonnanofiber (CNF) aerogels by engineeringthe thermal decomposition chemistry ofnanofibrillated wood cellulose. This worksuggests great promise in developingnew families of carbon aerogels based onthe controlled pyrolysis of sustainablenanostructured precursors.

AngewandteChemieCommunications

7Angew. Chem. Int. Ed. 2018, 57, 1 – 7 � 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim www.angewandte.org

These are not the final page numbers! � �

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