scholarly journals Nitrogen Doped Superactivated Carbons Prepared at Mild Conditions as Electrodes for Supercapacitors in Organic Electrolyte

2020 ◽  
Vol 6 (3) ◽  
pp. 56
Author(s):  
María José Mostazo-López ◽  
Ramiro Ruiz-Rosas ◽  
Tomomi Tagaya ◽  
Yoshikiyo Hatakeyama ◽  
Soshi Shiraishi ◽  
...  
Keyword(s):  
Surface Chemistry ◽  
Activated Carbons ◽  
Inert Atmosphere ◽  
Electrochemical Stability ◽  
Organic Electrolyte ◽  
Thermal Treatments ◽  
Nitrogen Doped ◽  
Chemical Treatments ◽  
Double Layer Capacitor ◽  
Nitrogen Functionalization

Nitrogen functionalization of a highly microporous activated carbon (SBET > 3000 m2/g), to be used as electrode of electric double layer capacitor (EDLC), was carried out by different methods based on organic chemistry protocols at low temperature and selective thermal post-treatments under inert atmosphere. The combination of both methods allowed the production of carbon materials with very similar surface area (2400–3000 m2/g) and different surface chemistry. The nitrogen functionalization by chemical methods produce the attachment of 4 at. % N (XPS) by consumption of oxygen functional groups. The thermal treatments rearrange the surface chemistry by decreasing and converting both nitrogen and oxygen moieties. The effect of surface chemistry on the performance of these materials as electrodes for symmetric supercapacitors was analyzed in organic electrolyte (1M TEMABF4/propylene carbonate). The devices showed high gravimetric capacitance (37–40 F/g) and gravimetric energy density (31–37 Wh/kg). The electrochemical stability of the EDLC was evaluated by a floating test under severe conditions of voltage and temperature. The results evidence an improvement of the durability of nitrogen-doped activated carbons modified by chemical treatments due to the decrease of detrimental oxygen functionalities and the generation of nitrogen groups with higher electrochemical stability.

scholarly journals Nitrogen-Doped Superporous Activated Carbons as Electrocatalysts for the Oxygen Reduction Reaction

Materials ◽  
2019 ◽  
Vol 12 (8) ◽  
pp. 1346 ◽  
Author(s):  
María José Mostazo-López ◽  
David Salinas-Torres ◽  
Ramiro Ruiz-Rosas ◽  
Emilia Morallón ◽  
Diego Cazorla-Amorós
Keyword(s):  
Oxygen Reduction Reaction ◽  
Oxygen Reduction ◽  
High Temperatures ◽  
Photoelectron Spectroscopy ◽  
Activated Carbons ◽  
Inert Atmosphere ◽  
Reduction Reaction ◽  
Treatment Temperature ◽  
Onset Potential ◽  
Nitrogen Functionalization

Nitrogen-containing superporous activated carbons were prepared by chemical polymerization of aniline and nitrogen functionalization by organic routes. The resulting N-doped carbon materials were carbonized at high temperatures (600–800 °C) in inert atmosphere. X-ray Photoelectron Spectroscopy (XPS) revealed that nitrogen amount ranges from 1 to 4 at.% and the nature of the nitrogen groups depends on the treatment temperature. All samples were assessed as electrocatalysts for the oxygen reduction reaction (ORR) in alkaline solution (0.1 M KOH) in order to understand the role of well-developed microporosity as well as the different nitrogen functionalities on the electrocatalytic performance in ORR. It was observed that nitrogen groups generated at high temperatures were highly selective towards the water formation. Among the investigated samples, polyaniline-derived activated carbon carbonized at 800 °C displayed the best performance (onset potential of 0.88 V versus RHE and an electron transfer number of 3.4), which was attributed to the highest concentration of N–C–O sites.

scholarly journals Analysis of the Effect of Conditions of Preparation of Nitrogen-Doped Activated Carbons Derived from Lotus Leaves by Activation with Sodium Amide on the Formation of Their Porous Structure

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1540
Author(s):  
Mirosław Kwiatkowski ◽  
Xin Hu
Keyword(s):  
Porous Structure ◽  
Activated Carbons ◽  
Structure Parameters ◽  
Mass Ratio ◽  
Nitrogen Doped ◽  
Adsorption Analysis ◽  
Lotus Leaves ◽  
The Impact ◽  
Sodium Amide ◽  
Numerical Clustering

This paper presents results of the analysis of the impact of activation temperature and mass ratio of activator to carbonized precursor R on the porous structure of nitrogen-doped activated carbons derived from lotus leaves by carbonization and chemical activation with sodium amide NaNH2. The analyses were carried out via the new numerical clustering-based adsorption analysis (LBET) method applied to nitrogen adsorption isotherms at −195.8 °C. On the basis of the results obtained it was shown that the amount of activator, as compared to activation temperatures, has a significantly greater influence on the formation of the porous structure of activated carbons. As shown in the study, the optimum values of the porous structure parameters are obtained for a mass ratio of R = 2. At a mass ratio of R = 3, a significant decrease in the values of the porous structure parameters was observed, indicating uncontrolled wall firing between adjacent micropores. The conducted analyses confirmed the validity of the new numerical clustering-based adsorption analysis (LBET) method, as it turned out that nitrogen-doped activated carbons prepared from lotus leaves are characterized by a high share of micropores and a significant degree of surface heterogeneity in most of the samples studied, which may, to some extent, undermine the reliability of the results obtained using classical methods of structure analysis that assume only a homogeneous pore structure.

Revisiting the Effect of Surface Chemistry on Adsorption of Water on Activated Carbons

1999 ◽  
Vol 103 (19) ◽  
pp. 3877-3884 ◽  
Author(s):  
Issa I. Salame ◽  
Andrey Bagreev ◽  
Teresa J. Bandosz
Keyword(s):  
Surface Chemistry ◽  
Activated Carbons ◽  
Adsorption Of Water ◽  
Effect Of Surface

Review: In-Water Systems to Reactively Manage Biofouling in Sea Chests and Internal Pipework

2017 ◽  
Vol 51 (2) ◽  
pp. 89-104 ◽  
Author(s):  
Abraham Growcott ◽  
Daniel Kluza ◽  
Eugene Georgiades
Keyword(s):  
Structural Complexity ◽  
Marine Species ◽  
Short Exposure ◽  
Thermal Treatments ◽  
Thermal Systems ◽  
Major Pathway ◽  
Chemical Treatments ◽  
Regulatory Constraints ◽  
Time Frames ◽  
Temperature Water

AbstractSea chests are cavities built into a vessel's hull to aid the efficiency of pumping seawater into internal pipework systems. Sea chests and internal pipework are known hotspots for the accumulation of biofouling, and vessel biofouling is a major pathway for the introduction and spread of nonindigenous marine species. The use of preventive strategies to minimize biofouling within sea chests and internal pipework is difficult due to their structural complexity; therefore, reactive methods to manage the associated biosecurity risk are required. This review examines the efficacy, environmental considerations, and cost of different systems to reactively manage sea chest and internal pipework biofouling within operationally realistic time frames (<3 days) and identifies those that warrant further investigation. Physical removal systems with recapture capability should be developed for accessible areas (e.g., grates), as such systems provide an operational benefit to the vessel. For internal and inaccessible surfaces, the development of thermal systems, particularly steam systems, is encouraged as they offer broad-spectrum efficacy at obtainable temperatures and require relatively short exposure periods. Compared to chemical treatments, thermal treatments are less influenced by environmental variables (e.g., temperature, water chemistry) and regulatory constraints.

scholarly journals Monolithic resorcinol–formaldehyde alcogels and their corresponding nitrogen-doped activated carbons

2020 ◽  
Vol 95 (3) ◽  
pp. 719-732
Author(s):  
Romain Civioc ◽  
Marco Lattuada ◽  
Matthias M. Koebel ◽  
Sandra Galmarini
Keyword(s):  
Activated Carbons ◽  
Resorcinol Formaldehyde ◽  
Nitrogen Doped
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