A biomass derived porous carbon for broadband and lightweight microwave absorption

AbstractWith the continuous progress of science and technology, the traditional magnetic material is no longer able to meet the new complex electromagnetic (EM) environment due to its high bulk density. Therefore, the novel excellent EM absorber with the feature of thin thickness, low density, broad absorption bandwidth and strong absorption intensity is highly desired. Herein, we fabricated a porous carbon with ultrahigh porosity through a facile KOH activation from biomass waste pumpkin seed shell for lightweight EM wave absorption application. By optimizing the porous structures, the strong absorption intensity of −50.55 dB is achieved at thin thickness of 1.85 mm under low filler content of only 10 wt %. More interestingly, a broad frequency bandwidth of 7.4 GHz could cover the whole Ku band. These outstanding microwave absorption performances, couple with low cost ingredients and ease of fabrication process enable the porous carbon framework as the next generation promising candidate for lightweight and remarkable EM absorber.

Download Full-text

Preparation of N-Doped Carbon Nanosheets from Sewage Sludge for Adsorption Studies of Cr(VI) from Aqueous Solution

Nanomaterials ◽

10.3390/nano9020265 ◽

2019 ◽

Vol 9 (2) ◽

pp. 265 ◽

Cited By ~ 6

Author(s):

Yi Wang ◽

Weinan Zhao ◽

Wanlan Zheng ◽

Shuang Chen ◽

Jinsheng Zhao

Keyword(s):

Sewage Sludge ◽

Porous Carbon ◽

Removal Rate ◽

Low Cost ◽

Waste Water Treatment ◽

Grand Challenge ◽

Koh Activation ◽

Thermal Regeneration ◽

Carbon Nanosheets ◽

Pore Size Distributions

Porous activated carbon with specific morphology and structure are of particular importance for waste water treatment, especially for the adsorption of toxic hexavalent chromium Cr(VI). However, the scalable and cheap production of such absorbents still suffer a grand challenge. Herein, a new type of N-doped nanosheet was innovatively prepared from easily available and low-cost sewage sludge via a facile and recyclable KOH activation method. The N-doped porous carbon nanosheets (N-SAC) produced by introduction of KOH and dicyandiamide, which performed favourable features for metal ions adsorption (93.2% for Cr(VI)) due to its high specific surface area, tuneable pore size distributions and good hydrophilicity. Additionally, the capacity also remained high after two cycles of adsorption by thermal regeneration, with 90.8% removal rate. The DFT calculation also approved that the doping of N could optimize the Mulliken charges distribution and improve the HOMO energy and improve the adsorption ability of N-SAC. This original proposal may inspire new possibility of creating porous carbon absorbents in a recyclable method.

Download Full-text

Facile fabrication of hierarchical porous carbon based on extract separated from coal with outstanding electrochemical performance

RSC Advances ◽

10.1039/c7ra05437h ◽

2017 ◽

Vol 7 (54) ◽

pp. 33843-33850 ◽

Cited By ~ 9

Author(s):

Peng Chang ◽

Zhihong Qin

Keyword(s):

Electrochemical Performance ◽

Porous Carbon ◽

Low Cost ◽

Koh Activation ◽

Porous Carbons ◽

Hierarchical Porous Carbon ◽

Hierarchical Porous ◽

Hierarchical Porous Carbons ◽

Facile Fabrication

Herein, a novel kind of hierarchical porous carbons were directly synthesized from low-cost extracts of coal by coupling nano MgO template with in situ KOH activation strategy.

Download Full-text

Janus-like Fe3O4/PDA vesicles with broadening microwave absorption bandwidth

Journal of Materials Chemistry C ◽

10.1039/c8tc02556h ◽

2018 ◽

Vol 6 (29) ◽

pp. 7790-7796 ◽

Cited By ~ 19

Author(s):

Xiaofeng Shi ◽

Zhengwang Liu ◽

Wenbin You ◽

Xuebing Zhao ◽

Renchao Che

Keyword(s):

Microwave Absorption ◽

Coupling Effect ◽

Magnetic Coupling ◽

Strong Absorption ◽

Frequency Range ◽

Absorption Intensity ◽

Absorption Bandwidth ◽

Measured Frequency ◽

Measured Frequency Range ◽

Pda Vesicles

Fe3O4/PDA vesicle Janus nanospheres were successfully synthesized, and they exhibited an ultra-wide effective band as wide as 11.6 GHz, covering 73% of the whole measured frequency range (2–18 GHz), and a strong absorption intensity as high as −50.0 dB due to the asymmetric polarization and magnetic coupling effect.

Download Full-text

N, S, O Self-Doped Porous Carbon Nanoarchitectonics Derived from Pinecone with Outstanding Supercapacitance Performances

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2020.17459 ◽

2020 ◽

Vol 20 (5) ◽

pp. 2728-2735 ◽

Cited By ~ 7

Author(s):

Di Zhang ◽

Yanchun Xue ◽

Jiale Chen ◽

Xingmei Guo ◽

Dandan Yang ◽

...

Keyword(s):

Porous Carbon ◽

Electrode Materials ◽

Low Cost ◽

High Specific Capacitance ◽

High Specific Surface Area ◽

Koh Activation ◽

Double Layer Capacitor ◽

Symmetric Supercapacitor ◽

Biomass N ◽

One Step

Biomass-derived porous carbons are considered as one of the most promising electrode materials for supercapacitors due to their low-cost and natural abundance. In this work, pinecone is used to fabricate biomass N, S, O-doped porous carbon via one-step carbonization process with KOH activation. By optimizing the additive amount of KOH and calcination temperature, the asprepared product shows a high specific surface area and pore volume up to 1593.8 m2 g−1 and 0.8582 cm3 g−1, respectively. As an electric double-layer capacitor (EDLC) electrode, the N, S, O-doped porous carbon exhibits a high specific capacitance of 285 F g−1 at 0.5 A g−1 and good rate performance with a capacitance retention of 78.6% from 0.5 to 20 A g−1. Furthermore, the as-assembled symmetric supercapacitor with 6 mol L−1 KOH as electrolyte possesses a promising energy density of 6.34 Wh kg−1 and a power density of 250 W kg−1. Outstanding cycling stability was also demonstrated with 94.4% capacitance retention after 10,000 charge/discharge cycles at 1 A g−1.

Download Full-text

Self-Nitrogen-Doped Carbon Nanosheets Modification of Anodes for Improving Microbial Fuel Cells’ Performance

Catalysts ◽

10.3390/catal10040381 ◽

2020 ◽

Vol 10 (4) ◽

pp. 381

Author(s):

Xiaoye Xing ◽

Zhongliang Liu ◽

Wenwen Chen ◽

Xiaoge Lou ◽

Yanxia Li ◽

...

Keyword(s):

Fuel Cells ◽

Porous Carbon ◽

Microbial Fuel Cells ◽

Carbon Nanomaterials ◽

Low Cost ◽

Bet Surface Area ◽

Koh Activation ◽

Maximum Output ◽

Carbon Cloth ◽

Carbon Nanosheets

Dandelion seeds (DSs) have the advantages of high nitrogen content, low cost and easy availability and thus are ideal carbon precursors for fabricating carbon nanomaterials. Herein, this paper prepared a carbon nanosheet material by one-step carbonizing DSs with KOH activation (self-doped-nitrogen porous carbon nanosheets (N-CNS)) and without KOH activation (unactivated self-doped-nitrogen porous carbon nanosheets (N-UA-CNS)), which could dope nitrogen atoms directly into carbon materials without additional processes. Scanning electron microscopy(SEM) images and X-ray diffraction(XRD) patterns both showed that N-CNS was of macro-porous structure, and beneficial for microorganisms’ growth. The Brunauer Emmett Teller(BET) surface area of N-CNS was 2107.5 m2 g−1, which was much higher than that of N-UA-CNS. After carbon clothes were modified by the obtained materials, the internal resistance of both N-CNS-modified carbon cloth (N-CNS-CC) and N-UA-CNS-modified carbon cloth (N-UA-CNS-CC) was greatly reduced and was found to be only 2.7 Ω and 4.0 Ω, respectively which are all significantly smaller than that of blank carbon cloth (65.1 Ω). These electrodes were assembled in microbial fuel cells (MFCs) as anode, and the operation experiments showed that the N-CNS modification shortened start-up time, improved output stability and increased maximum output voltage significantly. The maximum power density of N-CNS-CC MFC was 1122.41 mW m−2 which was 1.3 times of that of N-UA-CNS-CC MFC and 1.6 times of that of CC MFC. The results demonstrated that N-CNS was an ideal modification material for fabricating MFC anodes with simple preparation process and low cost.

Download Full-text

Characterization and Preparation of Nano-porous Carbon Derived from Hemp Stems as Anode for Lithium-Ion Batteries

Nanoscale Research Letters ◽

10.1186/s11671-019-3161-1 ◽

2019 ◽

Vol 14 (1) ◽

Cited By ~ 4

Author(s):

Zhongxiang Guan ◽

Zhiping Guan ◽

Zhigang Li ◽

Junhui Liu ◽

Kaifeng Yu

Keyword(s):

Activated Carbon ◽

Lithium Ion Batteries ◽

Porous Carbon ◽

Low Cost ◽

Specific Capacity ◽

High Capacity ◽

Lithium Ion ◽

Reversible Capacity ◽

Biomass Waste ◽

Rapid Preparation

Abstract As a biomass waste, hemp stems have the advantages of low cost and abundance, and it is regarded as a promising anode material with a high specific capacity. In this paper, activated carbon derived from hemp stems is prepared by low-temperature carbonization and high-temperature activation. The results of characterizations show the activated carbon has more pores due to the advantages of natural porous structure of hemp stem. The aperture size is mainly microporous, and there are mesopores and macropores in the porous carbon. The porous carbon has an excellent reversible capacity of 495 mAh/g after 100 cycles at 0.2 °C as the anode of lithium-ion battery. Compared with the graphite electrode, the electrochemical property of activated carbon is significantly improved due to the reasonable distribution of pore size. The preparation of the activated carbon provides a new idea for low cost and rapid preparation of anode materials for high capacity lithium-ion batteries.

Download Full-text

Meso/Microporous Carbons from Conjugated Hyper-Crosslinked Polymers Based on Tetraphenylethene for High-Performance CO2 Capture and Supercapacitor

Molecules ◽

10.3390/molecules26030738 ◽

2021 ◽

Vol 26 (3) ◽

pp. 738

Author(s):

Mohamed Gamal Mohamed ◽

Mahmoud M. M. Ahmed ◽

Wei-Ting Du ◽

Shiao-Wei Kuo

Keyword(s):

Porous Carbon ◽

Carbon Materials ◽

Total Pore Volume ◽

Specific Area ◽

High Specific Capacitance ◽

Koh Activation ◽

Co2 Uptake ◽

Crosslinked Polymers ◽

Good Thermal Stability ◽

Porous Carbon Materials

In this study, we successfully synthesized two types of meso/microporous carbon materials through the carbonization and potassium hydroxide (KOH) activation for two different kinds of hyper-crosslinked polymers of TPE-CPOP1 and TPE-CPOP2, which were synthesized by using Friedel–Crafts reaction of tetraphenylethene (TPE) monomer with or without cyanuric chloride in the presence of AlCl3 as a catalyst. The resultant porous carbon materials exhibited the high specific area (up to 1100 m2 g−1), total pore volume, good thermal stability, and amorphous character based on thermogravimetric (TGA), N2 adsoprtion/desorption, and powder X-ray diffraction (PXRD) analyses. The as-prepared TPE-CPOP1 after thermal treatment at 800 °C (TPE-CPOP1-800) displayed excellent CO2 uptake performance (1.74 mmol g−1 at 298 K and 3.19 mmol g−1 at 273 K). Furthermore, this material possesses a high specific capacitance of 453 F g−1 at 5 mV s−1 comparable to others porous carbon materials with excellent columbic efficiencies for 10,000 cycle at 20 A g−1.

Download Full-text

Highly reversible aluminium-sulfur batteries through effective sulfur confinement with hierarchical porous carbon

Journal of Materials Chemistry A ◽

10.1039/d1ta01422f ◽

2021 ◽

Author(s):

Dian Zhang ◽

Xu Zhang ◽

Boya Wang ◽

Shiman He ◽

Shiqi Liu ◽

...

Keyword(s):

Energy Density ◽

Porous Carbon ◽

Low Cost ◽

Hierarchical Porous Carbon ◽

Hierarchical Porous ◽

Application Prospects

Aluminium-sulfur (Al-S) batteries possess high research merits and application prospects owing to their high theoretical energy density, high safety and low cost. However, the deficiency of outstanding cathodes severely limits...

Download Full-text