scholarly journals Carbons as Catalysts in Thermo-Catalytic Hydrocarbon Decomposition: A Review

2020 ◽  
Vol 6 (2) ◽  
pp. 23
Author(s):  
Randy Vander Wal ◽  
Mpila Makiesse Nkiawete
Keyword(s):  
Energy Storage ◽  
Active Sites ◽  
Fossil Fuel ◽  
Carbon Materials ◽  
Carbon Deposition ◽  
Catalytic Decomposition ◽  
Solid Carbon ◽  
Thermocatalytic Decomposition ◽  
Forms Of Carbon ◽  
Decarbonization Process

Thermo-catalytic decomposition is well-suited for the generation of hydrogen from natural gas. In a decarbonization process for fossil fuel—pre-combustion—solid carbon is produced, with potential commercial uses including energy storage. Metal catalysts have the disadvantages of coking and deactivation, whereas carbon materials as catalysts offer resistance to deactivation and poisoning. Many forms of carbon have been tested with varied characterization techniques providing insights into the catalyzed carbon deposition. The breadth of studies testing carbon materials motivated this review. Thermocatalytic decomposition (TCD) rates and active duration vary widely across carbons tested. Regeneration remains rarely investigated but does appear necessary in a cyclic TCD–partial oxidation sequence. Presently, studies making fundamental connections between active sites and deposit nanostructures are few.

scholarly journals Review on Carbon/Polyaniline Hybrids: Design and Synthesis for Supercapacitor

Molecules ◽  
2019 ◽  
Vol 24 (12) ◽  
pp. 2263 ◽  
Author(s):  
Xiaoning Wang ◽  
Dan Wu ◽  
Xinhui Song ◽  
Wei Du ◽  
Xiangjin Zhao ◽  
...  
Keyword(s):  
Energy Storage ◽  
Hybrid Materials ◽  
Active Sites ◽  
High Performance ◽  
Electrode Materials ◽  
Carbon Materials ◽  
Low Cost ◽  
Specific Capacity ◽  
Chemical Properties ◽  
Combine Carbon

Polyaniline has been widely used in high-performance pseudocapacitors, due to its low cost, easy synthesis, and high theoretical specific capacitance. However, the poor mechanical properties of polyaniline restrict its further development. Compared with polyaniline, functionalized carbon materials have excellent physical and chemical properties, such as porous structures, excellent specific surface area, good conductivity, and accessibility to active sites. However, it should not be neglected that the specific capacity of carbon materials is usually unsatisfactory. There is an effective strategy to combine carbon materials with polyaniline by a hybridization approach to achieve a positive synergistic effect. After that, the energy storage performance of carbon/polyaniline hybridization material has been significantly improved, making it a promising and important electrode material for supercapacitors. To date, significant progress has been made in the synthesis of various carbon/polyaniline binary composite electrode materials. In this review, the corresponding properties and applications of polyaniline and carbon hybrid materials in the energy storage field are briefly reviewed. According to the classification of different types of functionalized carbon materials, this article focuses on the recent progress in carbon/polyaniline hybrid materials, and further analyzes their corresponding properties to provide guidance for the design, synthesis, and component optimization for high-performance supercapacitors.

scholarly journals Catalytic Decomposition of Ethanol over Bimetallic Nico Catalysts for Carbon Nanotube Synthesis

2020 ◽  
Author(s):  
Anand Kumar ◽  
Anchu Ashok
Keyword(s):  
Active Sites ◽  
Carbon Deposition ◽  
Catalytic Decomposition ◽  
Decomposition Reaction ◽  
Coke Deposition ◽  
Particle Analysis ◽  
Multiwalled Carbon ◽  
Ethanol Decomposition ◽  
Co Nanoparticles ◽  
Carbon Nanotube Synthesis

In this work we investigate the use of NiCo bimetal/oxide as catalyst for hydrogen production from ethanol, with a focus on the deactivation pattern and the nature of the observed carbon deposition. It is well known that sintering and coke deposition during decomposition reaction significantly reduces the activity of the catalysts at higher temperature, by blocking the active sites of the catalysts. During ethanol decomposition reaction, the cleavage of C-C bond produces adsorbed *CH4 and *CO species that further decompose to form carbonaceous compounds. FTIR in-situ analysis was conducted between 50 to 400°C for all the catalysts to understand the reaction mechanism and product selectivity. Cobalt was found to be selective for aldehyde and acetate, whereas bimetallic Ni-Co was selective for the formation of CO at 400°C along with aldehyde. Complete conversion of ethanol was observed at 350°C and 420°C for NiCo and Cobalt respectively indicating an improvement in the rate of conversion when Ni was added to cobalt. The crystallinity, morphology and particle analysis of the used catalyst after reaction were studied using XRD, SEM and TEM respectively. The XRD shows the complete phase change of porous NiCoO2 to NiCo alloy and SEM indicates the presence of fibrous structure on the surface with 91.7 % of carbon while keeping 1:1 ratio of Ni and Co after the reaction. The detailed analysis of carbon structure using HRTEM-STEM shows the simultaneous growth of carbon nano fibers (CNFs) and multiwalled carbon nanotubes (MWCNTs) that were favored on larger and smaller crystallites respectively. Analysis of carbon formation on individual Co catalyst and bimetallic NiCo catalyst shows a clear difference in the initiation pattern of carbon deposition. Metallic Co nanoparticles were found to be more mobile where Co disperses along the catalysts surface, whereas NiCo nanoparticles were relatively less mobile, and maintained their structure.

scholarly journals Research Progress on Applications of Polyaniline (PANI) for Electrochemical Energy Storage and Conversion

Materials ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 548 ◽  
Author(s):  
Zhihua Li ◽  
Liangjun Gong
Keyword(s):  
Fuel Cells ◽  
Energy Storage ◽  
Composite Structures ◽  
Active Sites ◽  
Carbon Materials ◽  
Rechargeable Batteries ◽  
Electrochemical Energy Storage ◽  
Research Progress ◽  
Energy Storage And Conversion ◽  
Electrochemical Energy

Conducting polyaniline (PANI) with high conductivity, ease of synthesis, high flexibility, low cost, environmental friendliness and unique redox properties has been extensively applied in electrochemical energy storage and conversion technologies including supercapacitors, rechargeable batteries and fuel cells. Pure PANI exhibits inferior stability as supercapacitive electrode, and can not meet the ever-increasing demand for more stable molecular structure, higher power/energy density and more N-active sites. The combination of PANI and other active materials like carbon materials, metal compounds and other conducting polymers (CPs) can make up for these disadvantages as supercapacitive electrode. As for rechargeable batteries and fuel cells, recent research related to PANI mainly focus on PANI modified composite electrodes and supported composite electrocatalysts respectively. In various PANI based composite structures, PANI usually acts as a conductive layer and network, and the resultant PANI based composites with various unique structures have demonstrated superior electrochemical performance in supercapacitors, rechargeable batteries and fuel cells due to the synergistic effect. Additionally, PANI derived N-doped carbon materials also have been widely used as metal-free electrocatalysts for fuel cells, which is also involved in this review. In the end, we give a brief outline of future advances and research directions on PANI.

scholarly journals Catalytic Decomposition of 2% Methanol in Methane over Metallic Catalyst by Fixed-Bed Catalytic Reactor

Energies ◽  
2021 ◽  
Vol 14 (8) ◽  
pp. 2220
Author(s):  
Ali Awad ◽  
Israr Ahmed ◽  
Danial Qadir ◽  
Muhammad Saad Khan ◽  
Alamin Idris
Keyword(s):  
Nickel Oxide ◽  
Active Sites ◽  
Carbon Nanofiber ◽  
Fixed Bed ◽  
Interaction Strength ◽  
Catalytic Decomposition ◽  
Catalytic Performance ◽  
Temperature Program Reduction ◽  
Impregnation Method ◽  
Forms Of Carbon

The structure and performance of promoted Ni/Al2O3 with Cu via thermocatalytic decomposition (TCD) of CH4 mixture (2% CH3OH) were studied. Mesoporous Cat-1 and Cat-2 were synthesized by the impregnation method. The corresponding peaks of nickel oxide and copper oxide in the XRD showed the presence of nickel and copper oxides as a mixed alloy in the calcined catalyst. Temperature program reduction (TPR) showed that Cu enhanced the reducibility of the catalyst as the peak of nickel oxide shifted toward a lower temperature due to the interaction strength of the metal particles and support. The impregnation of 10% Cu on Cat-1 drastically improved the catalytic performance and exhibited 68% CH4 conversion, and endured its activity for 6 h compared with Cat-1, which deactivated after 4 h. The investigation of the spent carbon showed that various forms of carbon were obtained as a by-product of TCD, including graphene fiber (GF), carbon nanofiber (CNF), and multi-wall carbon nanofibers (MWCNFs) on the active sites of Cat-2 and Cat-1, following various kinds of growth mechanisms. The presence of the D and G bands in the Raman spectroscopy confirmed the mixture of amorphous and crystalline morphology of the deposited carbon.

Core-shell nanostructured Zn-Co-O@CoS arrays for high-performance hybrid supercapacitors

2021 ◽  
Author(s):  
Yi He ◽  
Lei Xie ◽  
Shixiang Ding ◽  
Yujia Long ◽  
Xinyi Zhou ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Energy Storage ◽  
Active Sites ◽  
High Performance ◽  
Electronic Conductivity ◽  
Wide Distribution ◽  
Energy Storage Materials ◽  
Core Shell ◽  
Storage Materials ◽  
Hybrid Supercapacitors

Although the zinc oxide (ZnO) with wide distribution is one of the most attractive energy storage materials, the low electronic conductivity and insufficient active sites of bulk ZnO increase the...

scholarly journals High Capacity and Fast Kinetics of Potassium-Ion Batteries Boosted by Nitrogen-Doped Mesoporous Carbon Spheres

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Jiefeng Zheng ◽  
Yuanji Wu ◽  
Yong Tong ◽  
Xi Liu ◽  
Yingjuan Sun ◽  
...  
Keyword(s):  
Mesoporous Carbon ◽  
Active Sites ◽  
Carbon Materials ◽  
Potassium Ion ◽  
High Rate ◽  
Electrochemical Performances ◽  
Carbon Spheres ◽  
Fast Kinetics ◽  
Nitrogen Doped ◽  
Economic Price

AbstractIn view of rich potassium resources and their working potential, potassium-ion batteries (PIBs) are deemed as next generation rechargeable batteries. Owing to carbon materials with the preponderance of durability and economic price, they are widely employed in PIBs anode materials. Currently, porosity design and heteroatom doping as efficacious improvement strategies have been applied to the structural design of carbon materials to improve their electrochemical performances. Herein, nitrogen-doped mesoporous carbon spheres (MCS) are synthesized by a facile hard template method. The MCS demonstrate larger interlayer spacing in a short range, high specific surface area, abundant mesoporous structures and active sites, enhancing K-ion migration and diffusion. Furthermore, we screen out the pyrolysis temperature of 900 °C and the pore diameter of 7 nm as optimized conditions for MCS to improve performances. In detail, the optimized MCS-7-900 electrode achieves high rate capacity (107.9 mAh g−1 at 5000 mA g−1) and stably brings about 3600 cycles at 1000 mA g−1. According to electrochemical kinetic analysis, the capacitive-controlled effects play dominant roles in total storage mechanism. Additionally, the full-cell equipped MCS-7-900 as anode is successfully constructed to evaluate the practicality of MCS.

scholarly journals Carbons Formed in Methane Thermal and Thermocatalytic Decomposition Processes: Properties and Applications

2021 ◽  
Vol 7 (3) ◽  
pp. 50
Author(s):  
Emmi Välimäki ◽  
Lasse Yli-Varo ◽  
Henrik Romar ◽  
Ulla Lassi
Keyword(s):  
Thermal Decomposition ◽  
Hydrogen Production ◽  
Energy Systems ◽  
Hydrogen Gas ◽  
Solid Carbon ◽  
Hydrogen Economy ◽  
Decomposition Processes ◽  
Different Types ◽  
Decomposition Of Methane ◽  
Thermocatalytic Decomposition

The hydrogen economy will play a key role in future energy systems. Several thermal and catalytic methods for hydrogen production have been presented. In this review, methane thermocatalytic and thermal decomposition into hydrogen gas and solid carbon are considered. These processes, known as the thermal decomposition of methane (TDM) and thermocatalytic decomposition (TCD) of methane, respectively, appear to have the greatest potential for hydrogen production. In particular, the focus is on the different types and properties of carbons formed during the decomposition processes. The applications for carbons are also investigated.

Cyano Groups: New Active Sites of Porous Carbon Materials Achieving a Superior K-ion Storage

Carbon ◽  
2021 ◽  
Author(s):  
Xiang Gao ◽  
Wei Liu ◽  
Tianqi Wang ◽  
Jingrou Dai ◽  
Yuanyuan Pan ◽  
...  
Keyword(s):  
Porous Carbon ◽  
Active Sites ◽  
Carbon Materials ◽  
Porous Carbon Materials ◽  
Ion Storage ◽  
Cyano Groups
Sign in / Sign up

Export Citation Format

Share Document