Novel Straw-Derived Carbon Materials for Electromagnetic

Biomass resources are growing in concern in electromagnetic interference (EMI) shielding due to the advantages of low-cost, sustainability, and unique...
2 downloads 0 Views 1MB Size
Subscriber access provided by UNIV OF WESTERN ONTARIO

Article

Novel Straw-derived Carbon Materials for Electromagnetic Interference Shielding: A Waste-to-Wealth and Sustainable Initiative Xiaohui Ma, Bin Shen, Lihua Zhang, Zeping Chen, Yinfeng Liu, Wentao Zhai, and Wenge Zheng ACS Sustainable Chem. Eng., Just Accepted Manuscript • DOI: 10.1021/ acssuschemeng.9b01288 • Publication Date (Web): 30 Apr 2019 Downloaded from http://pubs.acs.org on May 6, 2019

Just Accepted “Just Accepted” manuscripts have been peer-reviewed and accepted for publication. They are posted online prior to technical editing, formatting for publication and author proofing. The American Chemical Society provides “Just Accepted” as a service to the research community to expedite the dissemination of scientific material as soon as possible after acceptance. “Just Accepted” manuscripts appear in full in PDF format accompanied by an HTML abstract. “Just Accepted” manuscripts have been fully peer reviewed, but should not be considered the official version of record. They are citable by the Digital Object Identifier (DOI®). “Just Accepted” is an optional service offered to authors. Therefore, the “Just Accepted” Web site may not include all articles that will be published in the journal. After a manuscript is technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Note that technical editing may introduce minor changes to the manuscript text and/or graphics which could affect content, and all legal disclaimers and ethical guidelines that apply to the journal pertain. ACS cannot be held responsible for errors or consequences arising from the use of information contained in these “Just Accepted” manuscripts.

is published by the American Chemical Society. 1155 Sixteenth Street N.W., Washington, DC 20036 Published by American Chemical Society. Copyright © American Chemical Society. However, no copyright claim is made to original U.S. Government works, or works produced by employees of any Commonwealth realm Crown government in the course of their duties.

Page 1 of 16 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Sustainable Chemistry & Engineering

Novel Straw-derived Carbon Materials for Electromagnetic Interference Shielding: A Waste-to-Wealth and Sustainable Initiative Xiaohui Ma,† ‡1 Bin Shen, ‡*1 Lihua Zhang, ‡ Zeping Chen, † ‡ Yinfeng Liu, † Wentao Zhai, ‡* and Wenge Zheng ‡ † School of Materials Science and Engineering, Shanghai University, Shanghai, 200444, China ‡ Ningbo Key Lab of Polymer Materials, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, No. 1219 Zhongguan West Road, Ningbo, Zhejiang province, 315201, China

Abstract: Biomass resources are getting growing concerns in electromagnetic interference (EMI) shielding due to the advantages of low-cost, sustainability and unique structural feature. From the perspective of “waste to wealth” and sustainable development, novel straw-derived hollow porous carbon-tube arrays (SCAs) have been fabricated through direct carbonization of wheat straw followed by orderly assembly for the first time. The resultant SCAs with increased SC diameter of ~1.7-3.3 mm showed not only low apparent density of ~72-33 mg/cm3 due to the presence of arrayed hollow macrostructure, but also high EMI SE of ~57.7-44.0 dB coming from both the strong EM reflection and conductive dissipation, as well as hierarchical internal multiple reflections. After the further construction of ultralight graphene aerogel (GA) in their hollow interior, the GA/SCAs with slightly increased density of only ~78-39 mg/cm3 exhibited obvious SE enhancement of ~66.1-70.6 dB compared to those of neat SCAs. In addition, the performance comparison between our SCAs and other previously reported carbon foams also revealed the more advanced configuration of hollow porous carbon-tube array for lightweight and high-performance EMI shielding application. KEYWORDS: Wheat straw; Waste to wealth; Hollow porous carbon-tube arrays; *

Corresponding authors: E-mail: [email protected] (B. Shen), [email protected] (W.T. Zhai).

1

These authors contributed equally to this work.

ACS Paragon Plus Environment

ACS Sustainable Chemistry & Engineering 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Graphene aerogel; Electromagnetic interference shielding;

ACS Paragon Plus Environment

Page 2 of 16

Page 3 of 16 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Sustainable Chemistry & Engineering

Introduction In order to solve the increasingly prominent electromagnetism jam resulting from the rapid development of modern military and electronics, exploring electromagnetic interference (EMI) shields that can effectively cut off the transmission of EM waves is of great significance.1-4 In recent years, macroscopic carbon architectures (MCAs), which are mainly fabricated via the self-assembling of carbon nanomaterials or chemical vapor deposition method, have been greatly investigated as high-efficiency EMI shields,5-12 since the outstanding electrical properties of carbon nanomaterials, such as carbon nanotubes (CNTs) and graphene,13 can be maximally utilized through the construction of such configurations, thereby endowing the MCAs or their polymerreinforced composites with high EMI shielding effectiveness (SE) even at low density or with ultrathin thickness owing to their excellent electrical conductivity. Nevertheless, the MCA fabrication process usually include the use of various chemicals or expensive precursors, or the generation of waste water or solvents, which not only restrict their massive production, but also is non-environmentally friendly. Moreover, the reported structure of MCAs almost limited to foam (aerogel) or film, possibly due to the limited fabrication method, hindering the exploration of novel excellent EMI shields. Biomass resources are getting growing concerns in many fields, since the materials derived from biomass have the advantages of low-cost, nontoxicity, sustainability and renewability, as well as unique structural feature coming from the naturally optimized structures of biomass.14-16 Straw are agricultural biomass wastes that cannot be used but must be disposed of, and the global straw production has reached more than 700 million tons each year.17 In China, the Thirteen Five-Year Plan (2016-2020) requires to improve the comprehensive utilization of straw, and strengthen the prohibition of burning which can cause serious air pollution and harm human health. Therefore, the conversion of straw wastes into more worthy products is assuredly more meaningful in comparison with other valuable biomass, such as wood, from the perspective of “waste to wealth” and green development. Until now, the straw wastes have been converted into various derivatives,17-22 such as feed, organic fertilizer, ethanol, building materials, and activated carbon, etc. Since possessing natural optimized porous microstructure and ACS Paragon Plus Environment

ACS Sustainable Chemistry & Engineering 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

hollow macrostructure for transport of ions and moisture (Figure S1), they are believed to be a promising sustainable raw material for the fabrication of novel MCAs with unique configuration for high-performance EMI shielding. Herein, novel straw-derived hollow porous carbon-tube arrays (abbreviated as SCAs) have been fabricated through direct carbonization of wheat straw followed by orderly assembly. The resultant SCAs with increased SC diameter of ~1.7-3.3 mm showed not only low apparent density of ~72-33 mg/cm3 owing to the presence of arrayed hollow macrostructure, but also high EMI SE of ~57.7-44.0 dB. After the further construction of ultralight graphene aerogel (GA) in their hollow interior, the GA/SCAs with slightly increased density of only ~78-39 mg/cm3 exhibited obvious SE enhancement of ~66.1-70.6 dB in comparison with those of neat SCAs. The comparison of shielding performance between our SCAs and other previously reported carbon foams also revealed the more advanced configuration of hollow porous carbon-tube array for lightweight and high-performance EMI shielding application.

Experimental Section Material preparation The raw wheat straw was bought from Taobao E-Shop, and the SC materials were fabricated by pyrolyzing the wheat straw in flowing high-purity nitrogen at different carbonization temperature (CT) of ~600, 1000, and 1500 oC with a heating rate of ~5 oC/min.

Once the setting temperature was reached, they were annealed for another one

hour and then naturally cooled to around 50 oC under the same nitrogen flow. The SC samples with different outer diameter, but similar thickness of annular wall, were fabricated though choosing different parts of wheat straw. To fabricate graphene aerogel (GA)/SC hybrid, aqueous suspension of graphene oxide (GO) was first injected into a wheat straw from its lower port by syringe (as shown in Figure S1), so that all the air inside the hollow macrostructure could be replaced by GO suspension completely. Then, the upper end of the wheat straw is sealed by plasticine. Since the pressure of the liquid in the hollow macrostructure is less than the atmospheric pressure, the GO suspension would not drain out after removing the ACS Paragon Plus Environment

Page 4 of 16

Page 5 of 16 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Sustainable Chemistry & Engineering

syringe. Finally, both ends of the wheat straw were sealed with paraffin, and after being frozen for one night, the paraffin was removed and the GO-filled wheat straw was freeze-dried for one day to get GO-aerogel modified wheat straw, and the GA/SC hybrid could be obtained after being further carbonized at the temperature of 1500 °C in high-purity nitrogen flow. Material characterizations Scanning electron microscopy (SEM) were performed with a Hitachi S-4800 field emission at an accelerating voltage of 4 kV. The SEM samples for the SC and GA/SC materials were freeze-fractured with liquid nitrogen. Since the raw wheat straw has a certain toughness, it cannot be freeze-fractured in liquid nitrogen after many attempts. Finally, the SEM samples for the raw wheat straw were prepared by slowly cutting using a sharp blade. Raman spectra was motivated with a laser of 532 nm and recorded with Labram spectrometer in the range of 600-3500 cm-1. The S parameters including S11, S22, S12, and S21 were measured by vector network analyzer (VNA) named Rohde & Schwarz ZVA67 using the wave-guide (WR-90 with cross section of 22.86 × 10.16 mm2) in the X-band (8-12 GHz). The SE absorption (SEA) and SE reflection (SER), as well as reflection (R) coefficient and absorption (A) coefficient, were evaluated on the basis of the S parameters according to the equations as follows:23 𝑅 = |𝑆11|2, 𝑇 = |𝑆21|2, 𝐴 = 1 ― 𝑅 ― 𝑇

(1)

SE𝑅(dB) = ―10log (1 ― 𝑅), SE𝐴(dB) = ―10log (𝑇 (1 ― 𝑅)) SE𝑇(dB) = 10log

( ) = 𝑆𝐸 𝑃𝐼

𝑃𝑇

𝑅

+ 𝑆𝐸𝐴

(2)

(3)

where PI is the incident power and PT is the transmitted power. Before the measurement, a Through-Reflection-Line (TRL) calibration was implemented to reduce the system errors and minimize the background noise. The samples were cut into pieces with the same size as the cross-section of the waveguide, and the small gap between the sample and the waveguide walls was controlled within 0.5 mm by carefully cutting the samples, which was less than 5% of the short side of the waveguide. The SC diameter was measured by micrometer, and the sample density was calculated from their mass and volume based on more than ten specimens. ACS Paragon Plus Environment

ACS Sustainable Chemistry & Engineering 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Results and discussion As shown in Figure 1A, the color of raw wheat straw was golden yellow in the appearance (the structure of raw wheat straw is shown in Figure S2), and the SC sample turned into carbon black and occurred ~30% volume shrinkage due to the pyrolysis of cellulose into heteroaromatic biochar.24 SEM observation of the SC sample indicated that a millimeter-scaled hollow macrostructure was observed in its transversal section, and inside the annular wall, it was consisted of many well-organized closed microcellular cells sized at tens of microns with gradient arrangement, which built a hierarchical porous structure (Figure 1B). There could also been seen interesting smiley patterns (marked by a circle) in some certain regions where much smaller cells appeared around the large cells. SEM images in Figure 1C further revealed the regular oriented cylindrical shapes of microcellular cells along the longitudinal section, with length of hundreds of microns, suggesting the anisotropic characteristic. Furthermore, unlike the smooth inner surface, many mouth-like pores appeared on the outer surface of the annular wall (Figure 1D), which should originate from the gas exchange stomates in the straw plants due to the natural growth.

Figure 1. (A) Optical photos showing the appearance of raw wheat straw and the SC samples. (B-D) SEM images exhibiting the morphology of the transversal cross-section

ACS Paragon Plus Environment

Page 6 of 16

Page 7 of 16 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Sustainable Chemistry & Engineering

(B), longitudinal cross-section (C), and outer surface (D) for the SC sample with the carbonization temperature of 1500 oC. To construct novel configuration for superior EMI shielding, the SC samples with very similar diameter were orderly assembled into array structures (Figure 2A), and then was packaged with paraffin for the measurements of EMI SE. Since the size of wheat straw gradually decreases from the root to the top, the SC samples with different outer diameter of ~1.7±0.1, ~2.6±0.1 and ~3.3±0.1 mm were also fabricated though choosing different parts of wheat straw (Figure 2B), and the corresponding SCAs were named as S-SCA, M-SCA, and L-SCA. Figure 2C displayed the measured SE curves in the X-band. When increasing the CT from 600 to 1500 oC, the average SE total of SSCA improved significantly from ~11.6 dB to ~42.2 and ~57.7 dB because of both improved SE absorption and SE reflection (Figure 2D), possibly due to their enhanced electrical properties (the electrical conductivity of the SC samples is difficult to test due to their hierarchical structure), which can be indirectly seen from their increased sp2 carbon domains as confirmed by Raman spectra in Figure S3 (their ID/IG ratio decreased from ~2.63 to ~2.17 and ~1.53 with the elevated CT).23 Moreover, the increased R and decreased A coefficient (Figure 2E) indicated that the improved SE value for the SCA sample with elevated CT mainly resulted from the enhancement of microwave reflection, and though the absorption of microwaves penetrating the SCA has been improved, the total microwave absorption for the SCA sample with the elevated CT was reduced. The absorption ability of the SCA sample with high CT was slower compared with that of as thin as possible structures for practical applications like CVD graphene and other carbon films reported in some works.25 The high EMI SE of the SCAs should come from not only strong EM reflection and conductive dissipation induced by high electrical conductivity,23 but also hierarchical multiple reflections and scattering of the microwaves in the saw-tooth arc-shaped peaks (Figure 2A),26 annular wall, arrayed hollow macrostructure, as well as numerous microcellular cells (Figure 3).2, 10, 27, 28

ACS Paragon Plus Environment

ACS Sustainable Chemistry & Engineering 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Figure 2. (A) Schematic illustrating the array structure of the SCAs, as well as the sawtooth arc-shaped peaks and arrayed hollow macrostructure. (B) SEM images showing the SC samples with different outer diameter. (C) SE total, (D) SEA-SER contributions and (E) R-A coefficients in the X-band of the SCAs with elevated CT. (F) SE total, (G) SEA-SER contributions and (H) R-A coefficients in the X-band of the SCAs with increased SC diameter.

Figure 3. Schematic illustrating the internal multiple reflections of the microwaves in the annular wall, arrayed hollow macrostructure, and numerous microcellular cells.

ACS Paragon Plus Environment

Page 8 of 16

Page 9 of 16 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Sustainable Chemistry & Engineering

Furthermore, the different SC diameter should inevitably influence the shielding performance of the SCAs. Using the CT of 1500 oC as an example, the average SE total reduced from ~57.7 dB for S-SCA to ~50.8 and ~44.0 dB for M-SCA and L-SCA due to the reduced SE absorption and SE reflection (Figure 2F-2G), indicating that the SE value is followed by the law of reducing with increasing the SC diameter. As marked in Figure 2A, the interface of the SCAs is very similar with the 3D saw-tooth structure mentioned in our previous work.26 Though the electrical properties and interface area remains nearly constant for the SCA with increased SC diameter, those deeper sawtooth arc-shaped peaks may induce more internal multiple reflections (or possible constructive interference) of the incident microwaves for dissipation by absorption,7, 26, 29

thereby reducing the value of SE reflection. Besides, the decreased number of hollow

carbon-tube for the SCA with increased SC diameter may also result in the reduction of multiple reflections of the microwaves penetrating its arrayed hollow macrostructure (Figure 3),2, 10, 27, 28 which is stronger than that enhanced by deeper saw-tooth structure, thus leading to the weakening of SE absorption. Further calculation of R-A coefficients of the SCAs with increased SC diameter (Figure 2H) suggested the weakening of their microwave reflection, but the enhancement of their total microwave absorption.

Figure 4. (A) Schematic illustrating the fabrication process of GA/SC hybrid. (B-D) SEM images showing the morphology of the transversal cross-section (B), longitudinal cross-section (C), and inner surface (D) for the GA/SC hybrid.

ACS Paragon Plus Environment

ACS Sustainable Chemistry & Engineering 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

On the other hand, the hollow macrostructure of the SC samples also provides a space for further modification of the materials to improve the shielding performance. As a demonstration, a graphene aerogel (GA) network was constructed within the SC sample through the procedures as shown in Figure 4A, where GO suspension (3 mg/ml) was first injected into a wheat straw, and subsequently the GO-filled wheat straw was freeze-dried and then carbonized at 1500 °C in an inert atmosphere to obtain GA/SC hybrid. SEM observation of both transversal and longitudinal sections in Figure 4B-4D confirmed that, except for possessing the anisotropic porous microstructure similar with neat SC sample, the as-fabricated GA/SC hybrid had an interconnected macroporous graphene network with pore size of hundreds of microns in its hollow interior. At higher magnification, it can be seen that the pore walls were composed of thin layers of stacked graphene sheets and the physical cross-links of the network were formed by the partial overlapping of the graphene layers. To investigate the EMI SE, the GA/SC hybrids with outer diameter of ~1.7±0.1, ~2.6±0.1 and ~3.3±0.1 mm were also assembled into the same array structure, and the result was exhibited in Figure 5A. As expected, the modification with GA network significantly improved the average SE total to ~66.1, ~70.6, and ~69.8 dB for SGA/SCA, M-GA/SCA, and L-GA/SCA, showing average increment around ~15%, ~39%, and ~59% in comparison with those of neat SCAs, respectively. However, thanks to the ultralow GA density, the apparent density of S-GA/SCA, M-GA/SCA, and L-GA/SCA only increased from ~72, ~43 and ~33 to ~78, ~48 and ~39 mg/cm3, indicating the realization of obvious SE enhancement without obviously increasing the sample density. The increased value of SE absorption and almost the same SE reflection (Figure 5B) strongly suggested that such obvious SE enhancement should attribute to the enhanced dissipation of microwaves penetrating the GA/SCA material. It is because that the inside GA network with highly porous characteristic could dissipate more microwaves by the conduction and relaxation loss as well as internal multiple reflections.9,

10, 27, 30

Moreover, the interfaces between the inner surface of SC and

graphene sheets of GA could also induce effective interfacial polarization,31 thereby further improving the absorption ability. In addition, the GA/SCA with increased SC

ACS Paragon Plus Environment

Page 10 of 16

Page 11 of 16 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Sustainable Chemistry & Engineering

diameter can accommodate larger volumes of GA network, thereby exhibiting stronger SE enhancement.

Figure 5. (A) SE total and (B) SEA-SER contributions in the X-band of the GA/SCAs comparison to neat SCAs with the same SC diameter. (C) The performance comparison between the SCAs (or GA/SCAs) and previously reported (wood, sugarcane)-derived carbon foams, as well as other carbon-based foams. The performance comparison between the SCAs and previously reported (wood, sugarcane)-derived homogeneous carbon foams (WDC or SDC), which possessed similar anisotropic porous carbon structure, was further conducted in Figure 5C. As seen, the high EMI SE together with their low density resulting from the presence of hollow macrostructure in the SC materials endows the S-SCA, M-SCA and L-SCA with ideal specific SE (SSE, defined as SE total divided by density) of ~800, ~1180 and 1335 dB/(g/cm3). The value was higher that of WDC (~330-460 dB/(g/cm3) at a density of ~120 mg/cm3 and a thickness of ~1.5-4.5 mm),14 or SDC (~790-370 dB/(g/cm3) at a density of ~54-121 mg/cm3 but a much larger thickness of ~10 mm),15 suggesting that our SCAs could offer higher shielding efficiency at a lower density possibly owing to the hierarchical multiple reflections induced by the saw-tooth arc-shaped peaks and arrayed hollow macrostructure, indicating the more advanced configuration of hollow ACS Paragon Plus Environment

ACS Sustainable Chemistry & Engineering 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

porous carbon-tube arrays for superior and lightweight EMI shielding. Moreover, the S-GA/SCA, M-GA/SCA, and L-GA/SCA exhibited enhanced SSE of ~850, ~1470 and ~1780 dB/(g/cm3), which was also higher than that of WDC@G@AgNWs or most of carbon foams with similar sample thickness. More excellent SSE was also reported in GGF, CNT-MLGEP and GLDC possibly due to the much higher electrical properties or much more enhanced interfacial polarization,10, 27, 31-40 but the simple fabrication process of SCAs and its waste-to-wealth and sustainable characteristic suggested its highly competitiveness for practical application like other lightweight EMI shielding materials.41-43

Conclusions In this work, the SC materials with hollow macrostructure and anisotropic porous characteristic were fabricated through direct carbonization of wheat straw. After being orderly assembled into array structure, the novel SCA configuration could be obtained and the resultant SCAs with increased SC diameter of ~1.7-3.3 mm showed not only low density of ~72-33 mg/cm3 due to the presence of arrayed hollow macrostructure, but also high EMI SE of ~57.7-44.0 dB coming from both the strong EM reflection and conductive dissipation, as well as hierarchical internal multiple reflections. The further construction of ultralight GA network in their hollow interior could endow the resultant GA/SCAs with slightly increased density of only ~78-39 mg/cm3 but improved EMI SE of ~66.1-70.6 dB compared to those of neat SCAs, indicating the realization of obvious SE enhancement without obviously increasing the sample density. Furthermore, the performance comparison between our SCAs and other previously reported carbon foams also revealed the more advanced configuration of hollow porous carbon-tube array for lightweight and high-performance EMI shielding application.

Acknowledgements The authors would like to acknowledge Dr. Da Yi from Zhejiang University for valuable discussion. This work was supported by National Natural Science Foundation

ACS Paragon Plus Environment

Page 12 of 16

Page 13 of 16 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Sustainable Chemistry & Engineering

of China (51603218, 51573202), and Natural Science Foundation of Ningbo (2018A610004).

Supporting Information The Supporting Information is available free of charge on the ACS Publications website. Schematic illustrating the fabrication process of the GO-filled wheat straw (Figure S1), SEM images exhibiting the morphology of raw wheat straw (Figure S2), and Raman spectra of the SCAs with elevated carbonization temperature (Figure S3).

References (1) Shahzad, F.; Alhabeb, M.; Hatter, C. B.; Anasori, B.; Man Hong, S.; Koo, C. M.; Gogotsi, Y. Electromagnetic interference shielding with 2D transition metal carbides (MXenes). Science 2016, 353 (6304), 1137. (2) Liu, J.; Zhang, H. B.; Sun, R.; Liu, Y.; Liu, Z.; Zhou, A.; Yu, Z. Z. Hydrophobic, Flexible, and Lightweight MXene Foams for High‐Performance Electromagnetic‐Interference Shielding. Adv. Mater. 2017, 29 (38), 1702367. (3) Sun, R.; Zhang, H. B.; Liu, J.; Xie, X.; Yang, R.; Li, Y.; Hong, S.; Yu, Z. Z. Highly Conductive Transition Metal Carbide/Carbonitride(MXene)@polystyrene Nanocomposites Fabricated by Electrostatic Assembly for Highly Efficient Electromagnetic Interference Shielding. Adv. Funct. Mater. 2017, 27 (45), 1702807. (4) Wen, B.; Cao, M.; Lu, M.; Cao, W.; Shi, H.; Liu, J.; Wang, X.; Jin, H.; Fang, X.; Wang, W.; Yuan, J. Reduced Graphene Oxides: Light-Weight and High-Efficiency Electromagnetic Interference Shielding at Elevated Temperatures. Adv. Mater. 2014, 26 (21), 3484-3489. (5) Shen, B.; Zhai, W.; Zheng, W. Ultrathin Flexible Graphene Film: An Excellent Thermal Conducting Material with Efficient EMI Shielding. Adv. Funct. Mater. 2014, 24 (28), 4542-4548. (6) Paliotta, L.; De Bellis, G.; Tamburrano, A.; Marra, F.; Rinaldi, A.; Balijepalli, S. K.; Kaciulis, S.; Sarto, M. S. Highly conductive multilayer-graphene paper as a flexible lightweight electromagnetic shield. Carbon 2015, 89, 260-271. (7) Song, W.-L.; Fan, L.-Z.; Cao, M.-S.; Lu, M.-M.; Wang, C.-Y.; Wang, J.; Chen, T.-T.; Li, Y.; Hou, Z.-L.; Liu, J.; Sun, Y.-P. Facile fabrication of ultrathin graphene papers for effective electromagnetic shielding. J. Mater. Chem C 2014, 2 (25), 50575064. (8) Li, X.-H.; Li, X.; Liao, K.-N.; Min, P.; Liu, T.; Dasari, A.; Yu, Z.-Z. Thermally Annealed Anisotropic Graphene Aerogels and Their Electrically Conductive Epoxy Composites with Excellent Electromagnetic Interference Shielding Efficiencies. ACS Appl. Mater. Interfaces 2016, 8 (48), 33230-33239. (9) Chen, Z.; Xu, C.; Ma, C.; Ren, W.; Cheng, H.-M. Lightweight and Flexible

ACS Paragon Plus Environment

ACS Sustainable Chemistry & Engineering 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Graphene Foam Composites for High-Performance Electromagnetic Interference Shielding. Adv. Mater. 2013, 25 (9), 1296-1300. (10) Liu, J.; Liu, Y.; Zhang, H.-B.; Dai, Y.; Liu, Z.; Yu, Z.-Z. Superelastic and multifunctional graphene-based aerogels by interfacial reinforcement with graphitized carbon at high temperatures. Carbon 2018, 132, 95-103. (11) Jin Gyu, P.; Jeffrey, L.; Qunfeng, C.; Jianwen, B.; Jesse, S.; Richard, L.; Ben, W.; Chuck, Z.; James, S. B.; Leslie, K.; Percy, F.; David, D. Electromagnetic interference shielding properties of carbon nanotube buckypaper composites. Nanotechnology 2009, 20 (41), 415702. (12) Chen, Y.; Zhang, H.-B.; Yang, Y.; Wang, M.; Cao, A.; Yu, Z.-Z. HighPerformance Epoxy Nanocomposites Reinforced with Three-Dimensional Carbon Nanotube Sponge for Electromagnetic Interference Shielding. Adv. Funct. Mater. 2016, 26 (3), 447-455. (13) Zhu, Y.; Murali, S.; Cai, W.; Li, X.; Suk, J. W.; Potts, J. R.; Ruoff, R. S. Graphene and Graphene Oxide: Synthesis, Properties, and Applications. Adv. Mater. 2010, 22 (35), 3906-3924. (14) Yuan, Y.; Sun, X.; Yang, M.; Xu, F.; Lin, Z.; Zhao, X.; Ding, Y.; Li, J.; Yin, W.; Peng, Q.; He, X.; Li, Y. Stiff, Thermally Stable and Highly Anisotropic Wood-Derived Carbon Composite Monoliths for Electromagnetic Interference Shielding. ACS Applied Materials & Interfaces 2017, 9 (25), 21371-21381. (15) Li, Y.-Q.; Samad, Y. A.; Polychronopoulou, K.; Liao, K. Lightweight and Highly Conductive Aerogel-like Carbon from Sugarcane with Superior Mechanical and EMI Shielding Properties. ACS Sustain. Chem. Eng. 2015, 3 (7), 1419-1427. (16) Xi, J.; Zhou, E.; Liu, Y.; Gao, W.; Ying, J.; Chen, Z.; Gao, C. Wood-based straightway channel structure for high performance microwave absorption. Carbon 2017, 124, 492-498. (17) Sangon, S.; Hunt, A. J.; Attard, T. M.; Mengchang, P.; Ngernyen, Y.; Supanchaiyamat, N. Valorisation of waste rice straw for the production of highly effective carbon based adsorbents for dyes removal. J. Clean. Prod. 2018, 172, 11281139. (18) Zhu, L.; Shen, F.; Smith, R. L.; Yan, L.; Li, L.; Qi, X. Black liquor-derived porous carbons from rice straw for high-performance supercapacitors. Chem. Eng. J. 2017, 316, 770-777. (19) Bai, X.; Wang, G.; Sun, Y.; Yu, Y.; Liu, J.; Wang, D.; Wang, Z. Effects of combined pretreatment with rod-milled and torrefaction on physicochemical and fuel characteristics of wheat straw. Bioresour. Technol. 2018, 267, 38-45. (20) Dong, L.; Cao, G.; Zhao, L.; Liu, B.; Ren, N. Alkali/urea pretreatment of rice straw at low temperature for enhanced biological hydrogen production. Bioresour. Technol. 2018, 267, 71-76. (21) Yin, X.; Lawrence, M.; Maskell, D.; Chang, W.-S. Construction and monitoring of experimental straw bale building in northeast China. Constr. Build. Mater. 2018, 183, 46-57. (22) Hussain, N.; Singh, A.; Saha, S.; Venkata Satish Kumar, M.; Bhattacharyya, P.; Bhattacharya, S. S. Excellent N-fixing and P-solubilizing traits in earthworm gutisolated bacteria: A vermicompost based assessment with vegetable market waste and

ACS Paragon Plus Environment

Page 14 of 16

Page 15 of 16 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

ACS Sustainable Chemistry & Engineering

rice straw feed mixtures. Bioresour. Technol. 2016, 222, 165-174. (23) Chen, Z.; Yi, D.; Shen, B.; Zhang, L.; Ma, X.; Pang, Y.; Liu, L.; Wei, X.; Zheng, W. Semi-transparent biomass-derived macroscopic carbon grids for efficient and tunable electromagnetic shielding. Carbon 2018, 139, 271-278. (24) Yuan, Y.; Ding, Y.; Wang, C.; Xu, F.; Lin, Z.; Qin, Y.; Li, Y.; Yang, M.; He, X.; Peng, Q.; Li, Y. Multifunctional Stiff Carbon Foam Derived from Bread. ACS Appl. Mater. Interfaces 2016, 8 (26), 16852-16861. (25) Kuzhir, P. P.; Paddubskaya, A. G.; Volynets, N. I.; Batrakov, K. G.; Kaplas, T.; Lamberti, P.; Kotsilkova, R.; Lambin, P. Main principles of passive devices based on graphene and carbon films in microwave-THz frequency range. J. Nanophoton. 2017, 11 (3), 032504. (26) Shen, B.; Li, Y.; Yi, D.; Zhai, W.; Wei, X.; Zheng, W. Strong flexible polymer/graphene composite films with 3D saw-tooth folding for enhanced and tunable electromagnetic shielding. Carbon 2017, 113 (Supplement C), 55-62. (27) Shen, B.; Li, Y.; Yi, D.; Zhai, W.; Wei, X.; Zheng, W. Microcellular graphene foam for improved broadband electromagnetic interference shielding. Carbon 2016, 102, 154-160. (28) Zhang, Y.; Huang, Y.; Zhang, T.; Chang, H.; Xiao, P.; Chen, H.; Huang, Z.; Chen, Y. Broadband and Tunable High-Performance Microwave Absorption of an Ultralight and Highly Compressible Graphene Foam. Adv. Mater. 2015, 27 (12), 2049-2053. (29) Liu, X.; Starr, T.; Starr, A. F.; Padilla, W. J. Infrared Spatial and Frequency Selective Metamaterial with Near-Unity Absorbance. Phys. Rev. Lett. 2010, 104 (20), 207403. (30) Shen, B.; Li, Y.; Zhai, W.; Zheng, W. Compressible Graphene-Coated Polymer Foams with Ultralow Density for Adjustable Electromagnetic Interference (EMI) Shielding. ACS Appl. Mater. Interfaces 2016, 8 (12), 8050-8057. (31) Zeng, Z.; Wang, C.; Zhang, Y.; Wang, P.; Seyed Shahabadi, S. I.; Pei, Y.; Chen, M.; Lu, X. Ultralight and Highly Elastic Graphene/Lignin-Derived Carbon Nanocomposite Aerogels with Ultrahigh Electromagnetic Interference Shielding Performance. ACS Appl. Mater. Interfaces 2018, 10 (9), 8205-8213. (32) Moglie, F.; Micheli, D.; Laurenzi, S.; Marchetti, M.; Mariani Primiani, V. Electromagnetic shielding performance of carbon foams. Carbon 2012, 50 (5), 19721980. (33) Zhang, L.; Liu, M.; Roy, S.; Chu, E. K.; See, K. Y.; Hu, X. Phthalonitrile-Based Carbon Foam with High Specific Mechanical Strength and Superior Electromagnetic Interference Shielding Performance. ACS Appl. Mater. Interfaces 2016, 8 (11), 74227430. (34) Song, W.-L.; Guan, X.-T.; Fan, L.-Z.; Cao, W.-Q.; Wang, C.-Y.; Cao, M.-S. Tuning three-dimensional textures with graphene aerogels for ultra-light flexible graphene/texture composites of effective electromagnetic shielding. Carbon 2015, 93, 151-160. (35) Kumar, R.; Dhakate, S. R.; Saini, P.; Mathur, R. B. Improved electromagnetic interference shielding effectiveness of light weight carbon foam by ferrocene accumulation. RSC Adv. 2013, 3 (13), 4145-4151. (36) Kumar, R.; Dhakate, S. R.; Gupta, T.; Saini, P.; Singh, B. P.; Mathur, R. B.

ACS Paragon Plus Environment

ACS Sustainable Chemistry & Engineering 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60

Effective improvement of the properties of light weight carbon foam by decoration with multi-wall carbon nanotubes. J. Mater. Chem. A 2013, 1 (18), 5727-5735. (37) Hong, X.; Chung, D. D. L. Carbon nanofiber mats for electromagnetic interference shielding. Carbon 2017, 111, 529-537. (38) Liu, C.; Ye, S.; Feng, J. The Preparation of Compressible and Fire-Resistant Sponge-Supported Reduced Graphene Oxide Aerogel for Electromagnetic Interference Shielding. Chem-Asian J. 2016, 11 (18), 2586-2593. (39) Crespo, M.; González, M.; Elías, A. L.; Pulickal Rajukumar, L.; Baselga, J.; Terrones, M.; Pozuelo, J. Ultra-light carbon nanotube sponge as an efficient electromagnetic shielding material in the GHz range. Phys. Status Solidi RRL 2014, 8 (8), 698-704. (40) Song, Q.; Ye, F.; Yin, X.; Li, W.; Li, H.; Liu, Y.; Li, K.; Xie, K.; Li, X.; Fu, Q.; Cheng, L.; Zhang, L.; Wei, B. Carbon Nanotube-Multilayered Graphene Edge Plane Core–Shell Hybrid Foams for Ultrahigh-Performance Electromagnetic-Interference Shielding. Adv. Mater. 2017, 29 (31), 1701583. (41) Zhang, K. L; Cheng, X. D.; Zhang, Y. J.; Chen, M.; Chen, H.; Yang, Y,; Song, W. L.; Fang, D. Weather-Manipulated Smart Broadband Electromagnetic Metamaterials. ACS Appl. Mater. Interfaces 2018, 10(47), 40815-40823. (42) Wang, Y.; Cheng, X. D.; Song, W. L.; Ma, C. J.; Bian, X. M.; Chen, M. Hydrosensitive sandwich structures for self-tunable smart electromagnetic shielding. Chem. Eng. J. 2018, 344, 342-352. (43) Cui, C. H.; Yan, D. X.; Pang, H.; Jia, L. C.; Xu, X.; Yang, S.; Xu, J. Z.; Li, Z. M. A high heat-resistance bioplastic foam with efficient electromagnetic interference shielding. Chem. Eng. J. 2017, 323, 29-36.

TOC Novel hollow porous carbon-tube arrays are derived from straw wastes for excellent EMI shielding from the perspective of sustainable development.

ACS Paragon Plus Environment

Page 16 of 16