Iron Modified Graphitized Carbon Aerogels for Sustainable Energy Applications

2013 ◽  
Vol 1491 ◽  
Author(s):  
Praveen Kolla ◽  
Kimberly Kerce ◽  
Yong Zhao ◽  
Joseph Houk ◽  
Yahaya Normah ◽  
...  
Keyword(s):  
Carbon Aerogel ◽  
Reduction Reaction ◽  
Carbon Aerogels ◽  
Nitride Phase ◽  
Iron Nitride ◽  
Graphene Layers ◽  
Energy Applications ◽  
Heat Treated ◽  
Structure Morphology ◽  
Iron Phase

ABSTRACTMesoporous carbon aerogel has been impregnated with iron (10 and 15 wt. %) as a catalyst for graphitization by wet incipient method. The iron modified and non-modified carbon aerogels were heat treated at 900°C, 1200°C, and 1400°C in argon. The crystal structure, morphology, and electro catalytic activity of the resulting nano-composites have been studied. It was found that, the degree of graphitization was proportional to the concentration of Iron phase and the ratio of iron to iron nitride phase in the heat-treated samples. In carbon aerogel sample sintered at 1200°C with 15 wt. % of iron phase, mesoporosity in the range of 3-4 nm and microporosity (< 2nm) was significantly improved by graphitization without affecting the Carbon Aerogels mesoporosity in 10-30 nm range. In this case of 15 wt. % iron doped samples, HRTEM analysis confirms the presence of uniformly distributed ∼43.5nm iron nanoparticles surrounded by graphene layers. Correspondingly, improved graphitization and presence of iron nitride resulted in 3.65 electron assisted oxygen reduction reaction.

Fe ultra-small particles anchored on carbon aerogels to enhance the oxygen reduction reaction in Zn-air batteries

2021 ◽  
Author(s):  
Jinjin Shi ◽  
Xinxin Shu ◽  
Chensheng Xiang ◽  
Hong Li ◽  
Yang Li ◽  
...  
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Active Sites ◽  
Carbon Aerogel ◽  
Reduction Reaction ◽  
Superior Performance ◽  
Carbon Aerogels ◽  
Small Particles

The Fe–N4–O–Fe–N4 moiety as active sites in ultra-small Fe particles anchored on carbon aerogel exhibited superior performance towards the oxygen reduction reaction.

Single iron atoms stabilized by microporous defects of biomass-derived carbon aerogels as high-performance cathode electrocatalysts for aluminum–air batteries

2019 ◽  
Vol 7 (36) ◽  
pp. 20840-20846 ◽  
Author(s):  
Ting He ◽  
Yaqian Zhang ◽  
Yang Chen ◽  
Zhenzhu Zhang ◽  
Haiyan Wang ◽  
...  
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
High Performance ◽  
Carbon Aerogel ◽  
Reduction Reaction ◽  
Alkaline Media ◽  
Single Atom ◽  
Carbon Aerogels ◽  
Cathode Catalyst ◽  
Hierarchical Porosity

Biomass-derived carbon aerogel with hierarchical porosity and FeN4 single atom sites outperforms platinum towards the oxygen reduction reaction in alkaline media and can be used as the cathode catalyst for aluminium–air batteries.

Facile solution synthesis of FeNx atom clusters supported on nitrogen-enriched graphene carbon aerogels with superb electrocatalytic performance toward the oxygen reduction reaction

2019 ◽  
Vol 7 (44) ◽  
pp. 25557-25566 ◽  
Author(s):  
Min Hong ◽  
Jianhang Nie ◽  
Xiaohua Zhang ◽  
Pengfei Zhang ◽  
Qin Meng ◽  
...  
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Specific Activity ◽  
Carbon Aerogel ◽  
Reduction Reaction ◽  
Alkaline Media ◽  
High Mass ◽  
Carbon Aerogels ◽  
Solution Synthesis ◽  
Atom Clusters

FeNx atom clusters anchored on N-enriched graphene carbon aerogel exhibited high mass specific activity (840 mA mgFe−1 at 0.80 V), positive E1/2 (0.90 V vs. RHE), excellent durability and strong tolerance to methanol and SCN− in alkaline media.

scholarly journals ZIF-67-aerogel-derived N-doped carbon nanotubes encapsulated with Co nanoparticles as efficient electrocatalysts

2021 ◽  
Vol 2085 (1) ◽  
pp. 012030
Author(s):  
Yan Li ◽  
Heng-Guo Wang
Keyword(s):  
Carbon Nanotubes ◽  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
Future Development ◽  
Carbon Aerogel ◽  
Reduction Reaction ◽  
Growth Strategy ◽  
Energy Applications ◽  
Co Nanoparticles

Abstract Electrocatalyst for oxygen reduction reaction (ORR) are essential for metal-air batteries. Herein, we design a self-catalyzed growth strategy for in-situ encapsulation of Co nanoparticles with N-doped carbon nanotubes (NCNT) on carbon aerogel (CA) (Co/NCNT/CA-1000). Using the zeolite imidazole framework (ZIF-67) as the cobalt source can catalyze the graphitization of melamine and facilitate the growth of NCNTs on the CA. Thanks to its unique structure, the Co/NCNT/CA-1000 exhibits favourable ORR properties (E1/2 = 0.80 V). This work offers an effective method for preparing high-active Co-based electrocatalysts and provides a foundation for the future development of electrochemical energy applications.

scholarly journals Environmentally Friendly and Multifunctional Shaddock Peel-Based Carbon Aerogel for Thermal-Insulation and Microwave Absorption

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Weihua Gu ◽  
Jiaqi Sheng ◽  
Qianqian Huang ◽  
Gehuan Wang ◽  
Jiabin Chen ◽  
...  
Keyword(s):  
Microwave Absorption ◽  
Thermal Insulation ◽  
Freeze Drying ◽  
Thermal Infrared ◽  
Carbon Aerogel ◽  
Carbon Aerogels ◽  
List Type ◽  
Drying Method ◽  
Cross Sectional ◽  
Compression Resistance

Highlights The eco-friendly shaddock peel-derived carbon aerogels were prepared by a freeze-drying method. Multiple functions such as thermal insulation, compression resistance and microwave absorption can be integrated into one material-carbon aerogel. Novel computer simulation technology strategy was selected to simulate significant radar cross-sectional reduction values under real far field condition. . Abstract Eco-friendly electromagnetic wave absorbing materials with excellent thermal infrared stealth property, heat-insulating ability and compression resistance are highly attractive in practical applications. Meeting the aforesaid requirements simultaneously is a formidable challenge. Herein, ultra-light carbon aerogels were fabricated via fresh shaddock peel by facile freeze-drying method and calcination process, forming porous network architecture. With the heating platform temperature of 70 °C, the upper surface temperatures of the as-prepared carbon aerogel present a slow upward trend. The color of the sample surface in thermal infrared images is similar to that of the surroundings. With the maximum compressive stress of 2.435 kPa, the carbon aerogels can provide favorable endurance. The shaddock peel-based carbon aerogels possess the minimum reflection loss value (RLmin) of − 29.50 dB in X band. Meanwhile, the effective absorption bandwidth covers 5.80 GHz at a relatively thin thickness of only 1.7 mm. With the detection theta of 0°, the maximum radar cross-sectional (RCS) reduction values of 16.28 dB m2 can be achieved. Theoretical simulations of RCS have aroused extensive interest owing to their ingenious design and time-saving feature. This work paves the way for preparing multi-functional microwave absorbers derived from biomass raw materials under the guidance of RCS simulations.

Ultramicroporous carbon aerogels encapsulating sulfur as the cathode for lithium–sulfur batteries

2021 ◽  
Author(s):  
Maryam Nojabaee ◽  
Brigitta Sievert ◽  
Marina Schwan ◽  
Jessica Schettler ◽  
Frieder Warth ◽  
...  
Keyword(s):  
Carbon Aerogel ◽  
Composite Cathode ◽  
Microporous Carbon ◽  
Carbon Aerogels ◽  
Lithium Sulfur Batteries ◽  
Lithium Sulfur

In the presented study, a sulfur infiltrated ultra-microporous carbon aerogel as a composite cathode for lithium sulfur batteries is developed and investigated.

scholarly journals Design Engineering, Synthesis Protocols, and Energy Applications of MOF-Derived Electrocatalysts

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Amr Radwan ◽  
Huihui Jin ◽  
Daping He ◽  
Shichun Mu
Keyword(s):  
Electronic Conductivity ◽  
Reduction Reaction ◽  
Design Engineering ◽  
High Porosity ◽  
Hydrogen Fuel ◽  
Fuel Production ◽  
Active Centers ◽  
Energy Applications ◽  
The Core ◽  
Metal Organic

AbstractThe core reactions for fuel cells, rechargeable metal–air batteries, and hydrogen fuel production are the oxygen reduction reaction (ORR), oxygen evolution reaction (OER), and hydrogen evolution reaction (HER), which are heavily dependent on the efficiency of electrocatalysts. Enormous attempts have previously been devoted in non-noble electrocatalysts born out of metal–organic frameworks (MOFs) for ORR, OER, and HER applications, due to the following advantageous reasons: (i) The significant porosity eases the electrolyte diffusion; (ii) the supreme catalyst–electrolyte contact area enhances the diffusion efficiency; and (iii) the electronic conductivity can be extensively increased owing to the unique construction block subunits for MOFs-derived electrocatalysis. Herein, the recent progress of MOFs-derived electrocatalysts including synthesis protocols, design engineering, DFT calculations roles, and energy applications is discussed and reviewed. It can be concluded that the elevated ORR, OER, and HER performances are attributed to an advantageously well-designed high-porosity structure, significant surface area, and plentiful active centers. Furthermore, the perspectives of MOF-derived electrocatalysts for the ORR, OER, and HER are presented.

scholarly journals Phase Stability of Iron Nitride Fe4N at High Pressure—Pressure-Dependent Evolution of Phase Equilibria in the Fe–N System

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3963
Author(s):  
Marius Holger Wetzel ◽  
Tina Trixy Rabending ◽  
Martin Friák ◽  
Monika Všianská ◽  
Mojmír Šob ◽  
...  
Keyword(s):  
High Pressure ◽  
Phase Equilibria ◽  
Phase Stability ◽  
Polymorphic Transition ◽  
Ex Situ ◽  
Stable Phase ◽  
Iron Nitride ◽  
Phase System ◽  
Target Composition ◽  
Heat Treated

Although the general instability of the iron nitride γ′-Fe4N with respect to other phases at high pressure is well established, the actual type of phase transitions and equilibrium conditions of their occurrence are, as of yet, poorly investigated. In the present study, samples of γ′-Fe4N and mixtures of α Fe and γ′-Fe4N powders have been heat-treated at temperatures between 250 and 1000 °C and pressures between 2 and 8 GPa in a multi-anvil press, in order to investigate phase equilibria involving the γ′ phase. Samples heat-treated at high-pressure conditions, were quenched, subsequently decompressed, and then analysed ex situ. Microstructure analysis is used to derive implications on the phase transformations during the heat treatments. Further, it is confirmed that the Fe–N phases in the target composition range are quenchable. Thus, phase proportions and chemical composition of the phases, determined from ex situ X-ray diffraction data, allowed conclusions about the phase equilibria at high-pressure conditions. Further, evidence for the low-temperature eutectoid decomposition γ′→α+ε′ is presented for the first time. From the observed equilibria, a P–T projection of the univariant equilibria in the Fe-rich portion of the Fe–N system is derived, which features a quadruple point at 5 GPa and 375 °C, above which γ′-Fe4N is thermodynamically unstable. The experimental work is supplemented by ab initio calculations in order to discuss the relative phase stability and energy landscape in the Fe–N system, from the ground state to conditions accessible in the multi-anvil experiments. It is concluded that γ′-Fe4N, which is unstable with respect to other phases at 0 K (at any pressure), has to be entropically stabilised in order to occur as stable phase system. In view of the frequently reported metastable retention of the γ′ phase during room temperature compression experiments, energetic and kinetic aspects of the polymorphic transition γ′⇌ε′ are discussed.

scholarly journals Nanostructured LiFe5O8 by a Biogenic Method for Applications from Electronics to Medicine

Nanomaterials ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 193
Author(s):  
Silvia Soreto Teixeira ◽  
Manuel P. F. Graça ◽  
José Lucas ◽  
Manuel Almeida Valente ◽  
Paula I. P. Soares ◽  
...  
Keyword(s):  
Spinel Ferrite ◽  
Sol Gel ◽  
Reaction Medium ◽  
Magnetic Hyperthermia ◽  
Magnetic Characteristics ◽  
Secondary Phases ◽  
Heat Treated ◽  
Structure Morphology ◽  
Sol Gel Process ◽  
Crystallite Sizes

The physical properties of the cubic and ferrimagnetic spinel ferrite LiFe5O8 has made it an attractive material for electronic and medical applications. In this work, LiFe5O8 nanosized crystallites were synthesized by a novel and eco-friendly sol-gel process, by using powder coconut water as a mediated reaction medium. The dried powders were heat-treated (HT) at temperatures between 400 and 1000 °C, and their structure, morphology, electrical and magnetic characteristics, cytotoxicity, and magnetic hyperthermia assays were performed. The heat treatment of the LiFe5O8 powder tunes the crystallite sizes between 50 nm and 200 nm. When increasing the temperature of the HT, secondary phases start to form. The dielectric analysis revealed, at 300 K and 10 kHz, an increase of ε′ (≈10 up to ≈14) with a tanδ almost constant (≈0.3) with the increase of the HT temperature. The cytotoxicity results reveal, for concentrations below 2.5 mg/mL, that all samples have a non-cytotoxicity property. The sample heat-treated at 1000 °C, which revealed hysteresis and magnetic saturation of 73 emu g−1 at 300 K, showed a heating profile adequate for magnetic hyperthermia applications, showing the potential for biomedical applications.

scholarly journals Light-induced levitation of ultralight carbon aerogels via temperature control

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Reo Yanagi ◽  
Ren Takemoto ◽  
Kenta Ono ◽  
Tomonaga Ueno
Keyword(s):  
Carbon Nanotubes ◽  
Heat Capacity ◽  
Porous Materials ◽  
Temperature Control ◽  
Light Absorption ◽  
Carbon Aerogel ◽  
Carbon Aerogels ◽  
Halogen Lamp ◽  
Absorption Properties ◽  
Air Density

AbstractWe demonstrate that ultralight carbon aerogels with skeletal densities lesser than the air density can levitate in air, based on Archimedes' principle, when heated with light. Porous materials, such as aerogels, facilitate the fabrication of materials with density less than that of air. However, their apparent density increases because of the air inside the materials, and therefore, they cannot levitate in air under normal conditions. Ultralight carbon aerogels, fabricated using carbon nanotubes, have excellent light absorption properties and can be quickly heated by a lamp owing to their small heat capacity. In this study, an ultralight carbon aerogel was heated with a halogen lamp and levitated in air by expanding the air inside as well as selectively reducing its density. We also show that the levitation of the ultralight carbon aerogel can be easily controlled by turning the lamp on and off. These findings are expected to be useful for various applications of aerogels, such as in communication and transportation through the sky.

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