Facile Synthesis of Carbon-Encapsulated Ni Nanoparticles Embedded

Oct 22, 2018 - State Key Laboratory of Metastable Materials Science & Technology and Key Laboratory for Microstructural Material Physics of Hebei Prov...
0 downloads 0 Views 1MB Size
Subscriber access provided by Kaohsiung Medical University

Article

Facile synthesis of carbon encapsulated Ni nanoparticles embedded into porous graphite sheets as high-performance microwave absorber Xia Du, Bochong Wang, Congpu Mu, Fusheng Wen, Jianyong Xiang, Anmin Nie, and Zhongyuan Liu ACS Sustainable Chem. Eng., Just Accepted Manuscript • DOI: 10.1021/ acssuschemeng.8b02944 • Publication Date (Web): 22 Oct 2018 Downloaded from http://pubs.acs.org on October 22, 2018

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 30 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

Facile synthesis of carbon encapsulated Ni nanoparticles embedded into porous graphite sheets as high-performance microwave absorber

Xia Dua,Bochong Wanga*, Congpu Mua, Fusheng Wena*, Jianyong Xianga, Anmin Niea and Zhongyuan Liua*

a

State Key Laboratory of Metastable Materials Science & Technology and Key

Laboratory for Microstructural Material Physics of Hebei Province, Yanshan University, Qinhuangdao 066004, People’s Republic of China

*Correspondence: [email protected]; [email protected]; [email protected]

1

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

Abstract The Ni@C nanohybrids were prepared by a unique and efficient method of annealing the organic carbon compound and metal nitrate. Morphology detection demonstrated the Ni nanoparticles were uniformly encapsulated into the carbon network. The microwave absorption of 10 wt% Ni@C nanohybrids with paraffin matrix was measured over the range of 1-18 GHz. The complex permittivity was adjusted by changing the carbon proportions due to the superior conductivity of graphite. The minimum RL value of -56 dB was obtained at 15.8 GHz with a thickness of 1.8 mm and the effective absorption bandwidth (RL≤-10 dB) was 5.4 GHz. Therefore, the Ni@C nanohybrids have great potential to be utilized as a high-efficiency and lightweight microwave absorber.

Key words: Nickel particles, porous carbon, reflection loss, microwave absorption, quarter-wavelength matching model

2

ACS Paragon Plus Environment

Page 2 of 30

Page 3 of 30 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 With the development of electric technology, electron devices are widely used and the electromagnetic radiation has become a central problem that harms the living environment and human health. Therefore, it is urgent to explore high-efficiency microwave absorbers with lightweight for solving the electromagnetic pollution. In the past decade, extensive efforts have been devoted to develop the high-performance microwave absorbing materials.1-7 Because of the high dielectric loss and low specific weight, carbonaceous materials become one of the most important microwave absorbers, such as porous carbon, graphene and carbon nanotubes.8-12 Specially, porous carbon has attracted much attention due to its extraordinary electrical conductivity, thermal stability, high specific surface area, facile fabricability and low cost.13-15 Meanwhile, the heterogeneous interfaces inside porous carbon deriving from the special porous microstructure are greatly beneficial to the multiple reflections of electromagnetic waves that will enhance the microwave absorption performance. For example, Liu synthesized graphene oxide/poly(vinyl alcohol) composite by thermal reduction. The minimum reflection loss reached -43.5 dB at 12.19 GHz with a thickness of 3.5 mm, and the effective bandwidth (below -10 dB) reached up to 7.47 GHz.16 As we know, the microwave absorbers with single composition and simple structure are unable to meet the strict requirements of thin thickness, lightweight, broad bandwidth and strong absorption.17-21 One valid way is to unite magnetic and carbonaceous materials 3

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

forming encapsulated structures that can equilibrate the electromagnetic parameters. Previous research results manifested that porous carbon/metal nanoparticles possessed superior microwave absorption performances, such as Fe/C/PPy,22 Co3O4/C/PGC,23 Fe3O4-NG,24 Ni/C,25 Co/C,26 CoNi/C,27 Fe3O4/C.28 However, the effects of the loading quality of metal nanoparticles and the structure of carbon/metal composites on microwave absorption were not full analyzed. In order to understand the microwave absorption mechanism and optimize the absorption property, it is quite necessary to systematically study the carbon encapsulated metal nanoparticle composites by changing the particle size and concentration. In this work, the Ni@C nanohybrids were synthesized by calcining the mixture of organic carbon compound and metal nitrate. The Ni nanoparticles with different size were uniformly dispersed in carbon matrix. Meanwhile, microwave absorption performances of Ni@C nanohybrids were systematically investigated and the absorption mechanisms were discussed.

Experimental section The Ni@C nanohybrids were synthesized by a unique annealing process that is graphically illustrated in Figure 1. Typically, Ni(NO3)2•6H2O (4 g), glucose (4 g, 8 g, 12 g, 16 g, 20 g) and anhydrous sodium carbonate (30 g) were dissolved in moderate deionized water and stirred to form homogenous solution. The anhydrous sodium carbonate was served as carrier and dispersant of the reaction to facilitate the uniformity 4

ACS Paragon Plus Environment

Page 4 of 30

Page 5 of 30 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

and nucleation of mixture. Then, the solution was bathed in water at 85 ℃ until all solvent evaporated to yield the as-precursor. The products were denoted as Ni@C1-1, Ni@C1-2, Ni@C1-3, Ni@C1-4 and Ni@C1-5 in accordance with different mass ratio of Ni(NO3)2•6H2O and glucose (1:1, 1:2, 1:3,1:4 and 1:5), respectively.

The composition

and element dispersion state of Ni@C 1-1, 1-3 and 1-5 precursors were measured by SEM and selected area elemental mapping, as shown in Figure S1, S2 and S3, respectively. It was clear shown that all elements were uniformly distributed in the precursors. By increasing the proportion of glucose, the precursor become smooth paste and the content of C element also increased. The grinded as-precursor was calcined in a tube furnace at 750 ℃ for 2 h under Ar atmosphere. After cooling to room temperature, the obtained powder was washed with deionized water to rinse anhydrous sodium carbonate and then dried in a vacuum oven at 60 ℃ for 12 h. The structure and morphology of Ni@C nanohybrids were investigated by scanning electron microscope (SEM, S-4800 Hitachi, Japan) and transmission electron microscopy (TEM, JEM-2010 JEOL, Japan). XRD patterns were preformed on a Rigaku SmartLab X-ray diffractometer with Cu Kα radiation (1.5406 Å). The graphitization degree of carbon matrix was researched by Raman spectroscopy with a laser radiation of 532 nm (Horiba Jobin Yvon Lab RAM). For characterizing the microwave absorption property, the toroidal samples (Φouter=7.0 mm, Φinner=3.04 mm) were prepared by mixing 10 wt% Ni@C nanohybrid with paraffin. The electromagnetic parameters (complex permittivity and complex permeability) were measured by a vector network analyzer (VNA) in the 5

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

frequency from 1 GHz to 18 GHz.

Results and discussion The XRD patterns of Ni@C samples with different ratio are presented in Figure 2a.The characteristic diffraction peaks locate at 44.5°, 51.8° and 76.4° corresponding to the (111), (200) and (220) planes of fcc Ni, respectively. In addition, the small peaks around 26° indicate the existence of carbon, resulting from the carbonization of glucose at high temperature.29 Meanwhile, the further investigation of carbon was examined by Raman spectra. As shown in Figure 2b, all Ni@C samples exhibit two peaks centering at 1345cm-1 and 1575cm-1, corresponding to D-band and G-band of carbon.30 The D-band corresponds to the vibration of sp3 defects and the disorder sites and the G-band relates to the in-plane sp2 hybridization vibration. Generally, the intensity ratio of two peaks (ID/IG) can be employed to figure out the disorder degree of carbon-based materials. The lower ratio manifests a higher degree of graphitization.31 In the Ni@C nanohybrid system, the ID/IG values are less than 1.0, which imply the successful carbonization of organic compounds in Ni@C nanocapsules. Furthermore, the peaks located around 2700 cm-1 relate to 2D-band in carbon. The intensity of 2D-band is much lower than the one of G-band which is consistent with the property of graphene foam. The porous properties of samples were investigated by niteogen adsorption-deposition isotherms and the corresponding pore-size distributions, as shown in Figure 2c and d. The isotherms display obvious hysteresis loop in the range of 0.4-1.0 P/P0, indicating the existence of 6

ACS Paragon Plus Environment

Page 6 of 30

Page 7 of 30 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

mesopores.32 The pore distributions of nanohybrids show an apparent peak in 4 nm derived from carbonization. Furthermore, the BET surface areas of Ni@C nanohybrids with different carbon proportions are 33.7 m2g-1, 145.8 m2g-1, 310.93 m2g-1, 292.6 m2g-1 and 382.3 m2g-1, respectively, which are larger than those of carbon-encapsulated nanoparticles in the previous work33, indicating the porous Ni@C nanohybrids were successfully prepared by a facile carbonization-annealing method. The achieved composites possess chemical bonds existing on the surface, benefiting the formation of interfacial polarization34 and exhibit high specific surface areas, facilitating microwave dissipation.35,36 The morphological and structural evolutions of porous Ni@C nanohybrids with different carbon proportions were analyzed by SEM and HRTEM. From Figure 3 a, d, g, j, m, the Ni nanoparticles show a little agglomeration under relatively high concentration and the particle size changes from 300 nm to 50 nm. By increasing the carbon proportion, Ni nanoparticles are uniformly wrapped in the porous carbon network without any agglomeration and the carbon shows a two-dimensional flake porous nanostructure with nearly transparent under TEM observation, seen in Figure 3 c, f, i, l, o. The size of Ni nanoparticles becomes smaller under higher carbon proportion, around 20 nm. The composition and element dispersion state of Ni@C 1-1, 1-3 and 1-5 nanohybrids were measured by SEM and selected area elemental mapping, as shown in Figure S4, S5 and S6, respectively. Clearly, the diameter of Ni particles decreases with increasing carbon proportion. The elemental mapping shows that C element and Ni element uniformly 7

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

distribute in the nanohybrids. The C element increases and the Ni element decreases with decreasing the ratio of Ni@C. From the HRTEM images in Figure 3, the interplanner spacings of Ni nanoparticles and carbon are 0.20 nm and 0.34 nm, corresponding to the (111) crystal planes of Ni and (002) crystal planes of carbon, respectively. These results are consistent with the XRD results in Figure 2a. The electromagnetic parameters of 10 wt% Ni@C nanohybrids mixed with the paraffin matrix were measured by vector network analyze between 1 GHz and 18 GHz at room temperature. Figure 4a,b display the complex permittivity and permeability with real parts (ε′ and μ′) and imaginary parts (ε″ and μ″). The real parts represent the energy storage and the imaginary parts imply the dissipation capabilities. In Figure 4a, it is obvious that the complex permittivity increases with the increasing carbon proportion, which is due to the high electrical conductivity of carbon material. Generally, the porous state of carbon material introduces many defects and dangling bonds that can act as polarization centers under magnetic field, leading to the intensive interfacial polarization in all samples. Considering the frequency effect, the permittivity values present a decreasing trend from 1 to 10 GHz and then gradually stabilize from 10 to 18 GHz. Because of the nonmagnetic carbon material, the permeability values of Ni@C composites are only determined by the content of Ni. Therefore, the values of μ′ and μ″ (Figure 4b) are approximately stable for all the samples, regardless of the carbon proportion and frequency, which is comptible with other research works.37-39 The dielectric loss and magnetic loss properties of the Ni@C composites are respectively 8

ACS Paragon Plus Environment

Page 8 of 30

Page 9 of 30 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

assessed by the dielectric loss tangent (tanδe = ε″/ε′) and magnetic loss tangent (tanδm = μ″/μ′) on the microwave frequency, as displayed in Figure 4c,d. It is found that the Ni@C 1-5 sample possess the largest tanδe values indicating the largest dielectric loss ability. This result is relevant to the interfacial polarization which derives from the heterogeneous interface between carbon and Ni nanoparticles inducing the accumulation of the space charges at the interfaces.40 In addition, the tanδm values are much smaller than the tanδe values and have less fluctuation with carbon proportion. The attenuation constant α plays an important role in the microwave attenuation, which represents the damping characteristics of materials. It can be figured up by the following formula:41



2 f  c



                   

r r  r r 

2

r

r

r

r

r

r

r

r

2

(1)

where c is the velocity of light, f is the frequency, εr′ and εr″ are complex permittivity, μr′ and μr″ are complex permeability. As shown in Figure 5, the attenuation constant values of all the samples express an upward trend in the whole frequency range, implying the high-frequency electromagnetic wave is more readily dissipated inside the absorbents and the Ni@C 1-5 sample keeps the largest value that is consistent with the analysis of the complex permittivity in Figure 4a. Generally, the lager attenuation constant means the better microwave absorption ability, but Ni@C 1-3 sample exhibit optimal RL value due to the cancellation of electromagnetic wave, which are explained by the quarter-wavelength matching model in the following. 9

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

Page 10 of 30

The microwave absorption performances can be achieved via computing the measured electromagnetic parameters on the basis of transmission line theory and the equations are described as follows: 1/2

    2 fd  1/2  Z in  Z 0  r  tanh  j    r  r     c    r 

RL  20 log

Z in  Z 0 Z in  Z 0

(2)

(3)

where Z0 represents the impendence of the air, Zin stands for the input impendence of composites, f is the microwave frequency, d is the thickness and c refers to the velocity of light. Figure 6 plots the reflection loss (RL) curves of 10 wt% Ni@C composites with different carbon proportions versus frequency at different thickness. Under low carbon concentration (Ni@C 1-1), permittivity value and attenuation constant are small that leads to a poor RL. The microwave absorption performance gradually improves with increasing carbon content. Clearly, Ni@C 1-3 sample has the best absorption performance. The minimum RL value achieves -56 dB at 15.8 GHz with a thickness of 1.8 mm. The effective absorption bandwidth (RL≤-10 dB) is 5.4 GHz. The RL performance of Ni@C 1-3 composite are compared with other carbon-based composites, which are summarized and shown in Table S1 in the Supporting Information. Meanwhile, the impedance matching characteristic is very important for the microwave absorption. The impedance characteristic of absorber should approach the one of free space, resulting in zero reflection at the interface. The frequency dependence of |Zin/Z0| for Ni@C 1-3, 1-4 and 1-5 nanohybrids are shown in Figure S7. The relationship between peak 10

ACS Paragon Plus Environment

Page 11 of 30 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

frequency and |Zin/Z0| at a certain thickness is indicated by the blue dash lines. Take the Ni@C 1-3 nanohybrids for example, when the thickness is 1.8 mm, the black line in Figure S7a, the minimum RL value is -56 dB under 15.8 GHz; at the same time, the value of |Zin/Z0| is very close to 1 at the same frequency point. For other nanohybrids, Ni@C 1-4 and 1-5, the values of |Zin/Z0| are lower than 1 through the whole frequency range. Then, the minimum RL frequency point is corresponding to the largest |Zin/Z0| value, shown in Figure S7d and S7f. To further investigate the microwave absorption property and mechanism of Ni@C composite, the microwave reflection loss at different thickness for Ni@C 1-3 are shown in Figure 7a. The minimum RL frequency and thickness satisfy the quarter-wavelength criteria, as the following equation: 42,43

tm 

n nc  m  4 4 f m  r r

(n=1, 3, 5 …)

(4)

The matching relation between absorber thickness and frequency can be interpreted by the quarter-wavelength (𝜆 4) matching model, seen in Figure 7b. When the sample thickness increases from 1.6 mm to 3.0 mm, the absorption peaks move from high frequency to low frequency region. The RL values below -20 dB appear from 8.1 GHz to 18 GHz, corresponding to the thickness from 1.6 mm to 3.0 mm. In general, RL values lower than -20 dB indicate 99% of microwave energy is absorbed, which means the absorber is available for the particular application. Therefore, the Ni@C composite displays excellent microwave absorption performance with a low metal content under a 11

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

small matching thickness. Consequently, it is promising to be a high efficiency and lightweight microwave absorber.

Conclusions In this work, Ni@C nanohybrids were successfully fabricated via annealing the mixture of organic carbon compound and metal nitrate. Morphology detection demonstrated the nanohybrids consist of the interconnected carbon network and the encapsulated nanoparticles, differing from the previous scattered carbon-wrapped samples. The microwave absorption of 10 wt% Ni@C composites was measured over the range of 1-18GHz. The complex permittivity can be adjusted by changing the carbon proportions due to the superior conductivity. The Ni@C 1-3 composite exhibited the optimal absorption intensity owing to the dielectric loss induced by carbon layer, the function of microstructure and the impedance matching. The minimum RL value of -56 dB was obtained at 15.8 GHz with a thickness of 1.8 mm and the effective absorption bandwidth (RL≤-10 dB) was 5.4 GHz. Therefore, the Ni@C nanohybrids have the potential to be a high-efficiency and lightweight microwave absorber in actual applications.

Supporting Information The Supporting Information is available free of charge on the ACS Publications website: The SEM images and the selected area elemental mapping of of Ni@C 1-1, 1-3 and 1-5 12

ACS Paragon Plus Environment

Page 12 of 30

Page 13 of 30 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

precursor; The SEM images and the selected area elemental mapping of of Ni@C 1-1, 1-3 and 1-5 nanohybrids; The frequency dependence of RL and the modulus of normalized input impendence |Zin/Z0| for the Ni@C 1-3, 1-4 and 1-5 nanohybrids; Microwave absorption performance of some Ni/C composites.

Acknowledgments This work is supported by the National Natural Science Foundation of China (Grant No. 51571172, 51732010, 51571171), Natural Science Foundation for Distinguished Young Scholars of Hebei Province (Grant No. E2017203095), Natural Science Foundation for Excellent Young Scholars of Hebei Province (Grant No. E2018203380).

References (1) Huang, Y. X.; Zhang, H. Y.; Zeng, G. X.; Li, Z. H.; Zhang, D. F.; Zhu, H. P.; Xie, R.F.; Zheng, L. M.; Zhu, J. H. The microwave absorption properties of carbon-encapsulated nickel nanoparticles/silicone resin flexible absorbing material. J. Alloys Comp. 2016, 682, 138-143, DOI 10.1016/j.jallcom.2016.04.289. (2) Tian, X.; Meng, F. B.; Meng, F. C.; Chen, X. N.; Guo,Y. F.; Wang, Y.; Zhu, W. J.; Zhou, Z. W. Synergistic Enhancement of Microwave Absorption Using Hybridized Polyaniline@helical CNTs with Dual Chirality. ACS Appl. Mater. Interfaces. 2017, 9, 15711−15718, DOI 10.1021/acsami.7b02607. (3) Zhou, C.; Geng, S.; Xu, X. W.; Wang, T. H.; Zhang, L. Q.; Tian, X. J.; Yang, F.; 13

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

Page 14 of 30

Yang, H. T.; Li, Y. F. Lightweight hollow carbon nanospheres with tunable sizes towards enhancement

in

microwave

absorption.

Carbon.

2016,

108,

234-241,

DOI

10.1016/j.carbon.2016.07.015. (4) Ruan, W. J.; Mu, C. P.; Wang, B. C.; Nie, A. M.; Zhang, C.; D, X.; Xiang, J.Y.; Wen, F. S.; Liu, Z. Y.; Metal-organic framework derived cobalt phosphosulfide with ultrahigh microwave absorption properties. Nanotechnology. 2018, 29(40) , 405703, DOI 10.1088/1361-6528/aad39b. (5) Wang, F.; Wu, L.; Zhou, J.; Jiang, Z.; Shen, B. Chemoselectivity-Induced Multiple Interfaces in MWCNT/Fe3O4@ZnO Heterotrimers for Whole X-Band Microwave Absorption. Nanoscale. 2014, 6, 12298−12302, DOI 10.1039/c4nr03040k. (6) Wu, H.; Wu, G.; Ren, Y.; Yang, L.; Wang, L.; Li, X. Co2+/Co3+ Ratio Dependence of Electromagnetic Wave Absorption in Hierarchical NiCo2O4-CoNiO2 Hybrids. J. Mater. Chem. C. 2015, 3, 7677−7690, DOI 10.1039/c5tc01716e. (7) Han, M.; Yin, X.; Kong, L.; Li, M.; Duan, W.; Zhang, L.; Cheng, L. Graphene-Wrapped ZnO Hollow Spheres with Enhanced Electromagnetic Wave Absorption

Properties.

J.

Mater.

Chem.

A.

2014,

2,16403−16409,

DOI

10.1039/c4ta03033h. (8) Yang, R. L.; Wang, B. C.; Xiang, J. Y.; Mu, C. P.; Zhang, C.; Wen, F. S.; Wang, C.; Su, C.; Liu, Z. Y. Fabrication of NiCo2‑Anchored Graphene Nanosheets by Liquid-Phase Exfoliation for Excellent Microwave Absorbers. ACS Appl. Mater. Interfaces. 2017, 9, 12673-22679, DOI 10.1021/acsami.6b16144. 14

ACS Paragon Plus Environment

Page 15 of 30 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

(9) Cao, M. S.; Wang, X. X.; Cao, W. Q.; Fang, X. Y.; Wen, B.; Yuan, J. Thermally Driven Transport and Relaxation Switching Self-Powered Electromagnetic Energy Conversion. Small, 2018, 14, 1800987, DOI 10.1002/smll.201800987. (10) Qiu, S.; Lyu H. L.; Liu, J. R.; Liu, Y. Z.; Wu, N. N.; Liu, W. Facile Synthesis of Porous Nickel/Carbon Composite Microspheres with Enhanced Electromagnetic Wave Absorption by Magnetic and Dielectric Losses. ACS Appl. Mater. Interfaces. 2016, 8, 20258−20266, DOI 10.1021/acsami.6b03159. (11) Zhou, N.; An, Q. D.; Xiao, Z. Y.; Zhai, S. R.; Shi, Z. Rational Design of Superior Microwave Shielding Composites Employing Synergy of Encapsulating Character of Alginate Hydrogels and Task-Specific Components (Ni NPs, Fe3O4/CNTs). ACS Sustainable Chem. Eng. 2017, 5, 5394−5407, DOI 10.1021/acssuschemeng.7b00711. (12) Wen, B.; Cao, M. S.; Lu, M. M.; C, W. Q.; Shi, H. L.; Liu, J.; Wang, X. X.; Jin, H. B.; Fang, X. Y.; Wang, W. Z.; Yuan, J. Reduced Graphene Oxides: Light-Weight and High-Efficiency Electromagnetic Interference Shielding at Elevated Temperatures. Adv, Mater. 2014, 26, 3484-3489, DOI 10.1002/adma.201400108. (13) Schedin, F.; Geim, A. K.; Morozov, S. V.; Hill, E. W.; Blake, P.; Katsnelson M. I.; Novoselov, K. S. Detection of Individual Gas Molecules Absorbed on Graphene. Nat. Mater. 2007, 6,652–655, DOI 10.1038/nmat1967. (14) Q, X.; Wang, L. X.; Zhu, H. L.; Guan, Y. K.; Zhang, Q. T. Lightweight and efficient microwave absorbing materials based on walnut shell-derived nano-porous carbon. Nanoscale. 2017, 9, 7408–7418, DOI 10.1039/c7nr02628e. 15

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

Page 16 of 30

(15) Dai, S. S.; Cheng, Y.; Quan, B.; Liang, X. H.; Liu, W.; Yang, Z. H.; Ji, G. B.; Du, Y. W. Porous-carbon-based Mo2C nanocomposites as excellent microwave absorber: a new exploration. Nanoscale. 2018, 10, 6945-6953, DOI 10.1039/c8nr01244j. (16) Liu, W. W.; Li, H.; Zeng, Q. P.; Duan, H. N.; Guo, Y. P.; Liu, C. Y.; Liu, H. Z. Fabrication

of

ultralight

three-dimensional

graphene

networks

with

strong

electromagnetic wave absorption properties. J. Mater. Chem. A. 2015, 3, 3739–3747, DOI 10.1039/c4ta06091a. (17) Tong, G. X.; Liu, F. T.; Wu, W. H.; Du, F. F.; Guan, J. G. Rambutan-Like Ni/MWCNT Heterostructures: Easy Synthesis, Formation Mechanism, and Controlled Static Magnetic and Microwave Electromagnetic Characteristics. J. Mater. Chem. A 2014, 2,7373−7382, DOI 10.1039/c4ta00117f.

(18) Wang, L.; Huang, Y.; Sun, X.; Huang, H. J.; Liu, P. B.; Zong, M.; Wang , Y. Synthesis and microwave absorption enhancement of graphene@Fe3O4@SiO2@NiO nanosheet

hierarchical

structures.

Nanoscale.

2014,

6,

3157–3164,

DOI

10.1039/C3nr05313j.

(19) Li, G.; Xie, T. S.; Yang, S. L.; Jin, J. H.; Jiang, J. M. Microwave Absorption Enhancement of Porous Carbon Fibers Compared with Carbon Nanofibers. J. Phys. Chem. C. 2012, 116, 9196-9201, DOI 10.1021/jp300050u.

16

ACS Paragon Plus Environment

Page 17 of 30 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

(20) Qi, X.; Xu, J.; Zhong, W.; Du, Y. Synthesis of High Purity Chain-Like Carbon Nanospheres in Ultrahigh Yield, and Their Microwave Absorption Properties. RSC Adv. 2015, 5, 16010−16016, DOI 10.1039/c4ra09321f.

(21) Wang, H.; Dai, Y. Y; Geng, D. Y.; Ma, S.; Li, D.; An, J.; He, J.; Zhang, Z. D.; CoxNi100−x nanoparticles encapsulated by curved graphite layers: controlled in situ metal-catalytic preparation and broadband microwave absorption. Nanoscale. 2015, 7, 17312-17319, DOI 10.1039/c5nr03745j.

(22) Jiang, L. W.; Wang, Z.H.; Geng, D. Y.; Wang, Y.; An, J.; He, J.; Li, D.; Liu, W.; Zhang, Z. D. Carbon-Encapsulated Fe Nanoparticles Embedded in Organic Polypyrrole Polymer as a High Performance Microwave Absorber. J. Phys. Chem. C 2016, 120, 28320−28329, DOI 10.1021/acs.jpcc.6b09445. (23) Wen, F. S.; Hou, H.; Xiang, J. Y.; Zhang, X. Y.; Su, Z. B.; Yuan, S. J.; Liu, Z. Y. Fabrication of carbon encapsulated Co3O4 nanoparticles embedded in porous graphitic carbon nanosheets for microwave absorber. Carbon. 2015, 89, 372-377, DOI 10.1016/j.carbon.2015.03.057. (24) Wang, X. X.; Ma, T.; Shu, J. C.; Cao, M. S. Confinedly tailoring Fe3O4 clusters-NG to tune electromagnetic parameters and microwave absorption with broadened bandwidth. Chem. Eng. J. 2018, 332, 321-330, DOI 10.1016/j.cej.2017.09.101. (25) Wang, H.; Dai, Y. Y.; Gong, W. J.; Geng, D. Y.; Han, Z.; Li, D.; Yang, T.; Ma, S.; Liu, W.; Zhang, Z. D. Optimal electromagnetic-wave absorption by enhanced dipole 17

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

polarization in Ni/C nanocapsules. Appl. Phys. Lett. 2012, 101, 083116, DOI 10.1063/1.4747811. (26) Zhang, D. F.; Xu, F. X.; Lin, J.; Yang, Z. D.; Zhang, M. Electromagnetic characteristics and microwave absorption properties of carbon-encapsulated cobalt nanoparticles in 2–18 GHz frequency range. Carbon. 2014, 80, 103-111, DOI 10.1016/j.carbon.2014.08.044. (27) Wang, H.; Dai, Y. Y.; Gong, W. J.; Geng, D. Y.; Ma, S.; Li, D.; Liu, W.; Zhang, Z. D. Broadband microwave absorption of CoNi@C nanocapsules enhanced by dual dielectric relaxation and multiple magnetic resonances. Appl. Phys. Lett. 2013, 102, 223113, DOI 10.1063/1.4809675. (28) Chen, Y.; Cao, J. M.; Li, Y.; Li, Z. Y.; Zhao, H. Q.; Ji, G. B.; Du, Y. W. The Outside-In Approach To Construct Fe3O4Nanocrystals/Mesoporous Carbon Hollow Spheres Core−Shell Hybrids toward Microwave Absorption. ACS Sustainable Chem. Eng. 2018, 6, 1427−1435, DOI 10.1021/acssuschemeng.7b03846. (29) Lei, Z. M.; Zhai, S. R.; Lv, J. L.; Fan, Y.; An, Q. D.; Xiao, Z. Y. Sodium alginate-based magnetic carbonaceous biosorbents for highly efficient Cr (VI) removal from water. RSC Adv. 2015, 5, 77932−77941, DOI 10.1039/c5ra13226f. (30) Zhu, J.; Li, K.; Xiao, M.; Liu, C.; Wu, Z.; Ge, J.; Xing, W. Significantly Enhanced Oxygen Reduction Reaction Performance of N-doped carbon by Heterogeneous Sulfur Incorporation: Synergistic Effect Between the Two Dopants in Metal-free Catalysts. J. Mater. Chem. A. 2016, 4, 7422−7429, DOI 10.1039/c6ta02419j. 18

ACS Paragon Plus Environment

Page 18 of 30

Page 19 of 30 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

(31) Huang, Y.; Wang, Y.; Li, Z.; Yang, Z.; Shen, C.; He, C. Effect of Pore Morphology on the Dielectric Properties of Porous Carbons for Microwave Absorption Applications. J. Phys. Chem. C. 2014, 118,26027−26032, DOI 10.1021/jp506999k. (32) Tshavhungwe, A. M.; Layh, M.; Coville, N. J. Cobalt Ion Incorporation Into Periodic Mesoporous Organosilica Materials Synthesized by Co-condensation of 1,2-Bistrimethoxysilylethane with 3-Glycidoxypropyltriethoxysilane. J. Sol-Gel. Technol. 20114, 29. 167-177, DOI 10.1023/b:jsst.0000023847.51893. (33) Xie, X. B.; Pang, Y.; Kikuchi, H.; Liu, T. The Synergistic Effects of Carbon Coating and Micropore Structure on The Microwave Absorption Properties of Co/CoO Nanoparticles.

Phys.

Chem.

Chem.

Phys.

2016,

18,

30507−30514,

DOI

10.1039/c6cp05099a. (34) Han, M.; Yin, X.; Kong, L.; Li, M.; Duan, W.; Zhang, L.; Cheng, L. Graphene-Wrapped ZnO Hollow Spheres With Enhanced Electromagnetic Wave Absorption

Properties.

J.

Mater.

Chem.

A

2014,

2,16403−16409,

DOI

10.1039/c4ta03033h. (35) Liu, wei.; Shao, Q. W.; Ji, G. B.; Liang, X. H.; Cheng, Y.; Quan, B.; Du, Y. W. Metal-organic-frameworks derived porous carbon-wrapped Ni composites with optimized impedance matching as excellent lightweight electromagnetic wave absorber. Chem. Eng. J. 2017, 313, 734-744, DOI 10.1016/j.cej.2016.12.117. (36) Zhao, B.; Fan, B. B.; Xu, Y. W.; Shao, G.; Wang, X. D.; Zhao, W. Y.; Zhang, R. Preparation of honeycomb SnO2 foams and configuration dependent microwave 19

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

Page 20 of 30

absorption features. ACS Appl. Mater. Interfaces. 2015, 7 (47), 26217−26225, DOI 10.1021/acsami.5b08383. (37) Zhang, C.; Wang, B. C.; Xiang, J. Y.; Su, C.; Wen, F. S.; Liu, Z. Y. Microwave Absorption Properties of CoS2 Nanocrystals Embedded into Reduced Graphene Oxide). ACS Appl. Mater. Interfaces. 2017, 9, 28868−28875, DOI 10.1088/1361-6528/aa9a2a. (38) Mu, C.; Song, J.; Wang, B.; Wen, F.; Zhang, C.; Wang, C.; Liu, Z.; Xiang, J. Facile-Synthesized Carbonaceous Photonic Crystals/Magnetic Particle Nanohybrids With Heterostructure as an Excellent Microwave Absorber. J. Alloy. Comp. 2018, 741, 814-820, DOI 10.1016/j.jallcom.2018.01.180. (39)

Mu,

C.;

Song,

J.; Wang, B.;

Zhang, C.;

Xiang,

J.;

Wen, F.;

Liu, Z.

Two Dimensional Materials and One Dimensional Carbon Nanotubes Composites for Mi crowave Absorption.

Nanotechnology.

2018,

29,

025704,DOI

10.1088/1361-6528/aa9a2a. (40) Li, D.; Liao, H. Y.; Hiroaki Kikuchi, Liu, T. Microporous Co@C Nanoparticles Prepared by Dealloying Co Al@C Precursors: Achieving Strong Wideband Microwave Absorption via Controlling Carbon Shell Thickness. ACS Appl. Mater. Interfaces. 2017, 9, 44704-44714, DOI 10.1021/acsami.7b13538. (41) Zhang, X. M.; Ji, G. B.; Liu, W.; Quan, B.; Liang, X. H.; Shang,C. M.; Cheng, Y.; Du, Y. W. Thermal conversion of an Fe3O4@metal-organic framework: a new method for an efficient Fe-Co/nanoporous carbon microwave absorbing material. Nanoscale. 2015, 7, 12932−12942, DOI 10.1039/c5nr03176a. 20

ACS Paragon Plus Environment

Page 21 of 30 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

(42) Wang, B.; Wei, J.; Yang, Y.; Wang, T.; Li, F. Investigation on peak frequency of the microwave absorption for carbonyl iron/epoxy resin composite, J. Magn. Magn. Mater. 2011, 323, 1101-1103, DOI 10.1016/j.jmmm.2010.12.028. (43) Xiang, J.; Li, J.; Zhang, X.; Ye, Q.; Xu, J.; Shen, X. Magnetic Carbon Nanofibers Containing

Uniformly

Dispersed

Fe/Co/Ni

Nanoparticles

as

Stable

and

High-Performance Electromagnetic Wave Absorbers. J. Mater. Chem. A. 2014, 2, 16905−16914, DOI 10.1039/c4ta03732d.

Figure 1. Schematic illustration for the synthesis of Ni@C nanohybrids.

21

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

22

ACS Paragon Plus Environment

Page 22 of 30

Page 23 of 30 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

Figure 2. (a) XRD patterns, (b) Raman spectra, (c) The nitrogen adsorption-deposition isotherms and (d) The corresponding BJH pore-size distribution of Ni@C nanohybrids with different carbon proportions.

23

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 3. (a,d,g,j,m) SEM images, (b,e,h,k,n) TEM images and (c,f,i,l,o) HR-TEM images of Ni@C 1-1, Ni@C 1-2, Ni@C 1-3, Ni@C 1-4 and Ni@C 1-5, respectively.

24

ACS Paragon Plus Environment

Page 24 of 30

Page 25 of 30 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

Figure 4. Frequency dependence of (a) real part and imaginary part of permittivity; (b) real part and imaginary part of permeability; (c) dielectric loss tangent and (d) magnetic loss tangent of Ni@C composites with different carbon proportions.

25

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 5. Attenuation constant of Ni@C composites with different carbon proportions.

26

ACS Paragon Plus Environment

Page 26 of 30

Page 27 of 30 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

27

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 6. Color map of reflection loss of Ni@C composites with different carbon proportions: (a) Ni@C 1-1, (b) Ni@C 1-2, (c) Ni@C 1-3, (d) Ni@C 1-4 and (e) Ni@C 1-5.

28

ACS Paragon Plus Environment

Page 28 of 30

Page 29 of 30 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

Figure 7. (a) Dependence of reflection loss on frequency at different thickness for Ni@C 1-3 composite; (b) Dependence of λ/4 thickness on frequency for Ni@C 1-3 composite.

29

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

Table of Contents

Brief synopsis of TOC Schematic illustration of Ni@C 1-3 nanohybrid and its TEM image. The excellent microwave absorption performance of Ni@C 1-3 nanocomposite.

30

ACS Paragon Plus Environment

Page 30 of 30