Renewable Nitrogen‐Doped Hydrothermal Carbons Derived from Microalgae

Abstract

Nitrogen‐doped carbon materials are synthesized via an effective, sustainable, and green one‐step route based on the hydrothermal carbonization of microalgae with high nitrogen content (ca. 11 wt %). The addition of the monosaccharide glucose to the reaction mixture is found to be advantageous, enhancing the fixation of nitrogen in the synthesized carbons, resulting in materials possessing nitrogen content in excess of 7 wt %, and leading to promising reaction yields. Increasing the amount of glucose leads to a higher nitrogen retention in the carbons, which suggests co‐condensation of the microalgae and glucose‐derived degradation/hydrolysis products via Maillard‐type cascade reactions, yielding nitrogen‐containing aromatic heterocycles (e.g., pyrroles) as confirmed by several analytical techniques. Increasing the HTC processing temperature leads to a further aromatization of the chemical structure of the HTC carbon and the formation of increasingly more condensed nitrogen‐containing functional motifs (i.e., pyridinic and quaternary nitrogen).

Coralline‐Like N‐Doped Hierarchically Porous Carbon Derived from Enteromorpha as a Host Matrix for Lithium‐Sulfur Battery

“…Scheme shows a scheme for the synthesis of CNHPC from enteromorpha. The washed and dried enteromorpha was first mixed with glucose solution for 18 h. The glucose was added to improve the yield and aid N‐doping of carbon . After that the mixed solution was hydrothermally carbonized at 180 °C for 24 h, followed by activation with KOH (KOH/carbon=4:1, by weight) at different temperatures (700 and 800 °C) for 1 h under N 2 atmosphere to obtain CNHPC.…”

“…The washed and dried enteromorphaw as first mixed with glucose solution for 18 h. The glucosew as added to improve the yield and aid N-doping of carbon. [22] After that the mixed solution was hydrothermally carbonized at 180 8C for 24 h, followed by activation with KOH (KOH/carbon = 4:1, by weight) at different temperatures (700 and 800 8C) for 1h under N 2 atmosphere to obtain CNHPC. Direct cabonizationo f enteromorphai ni nN 2 was found to give al ow yield of carbon and low content of nitrogen doping.…”

Hydrothermal conversion of biomass waste to activated carbon with high porosity: A review

“…Carbonization temperature is dependent on the type of starting materials and its decomposition temperature; a range of 150 to 350°C is typically employed [2,[10][11][12][13][14][15]. Hydrothermal carbonization results in efficient hydrolysis and dehydration of biomass and bestows the hydrochar with high OFG (oxygenated functional groups) content which makes it an effective precursor for the production of chemically activated carbon [8,16].…”

High Performance N‐Doped Carbon Electrodes Obtained via Hydrothermal Carbonization of Macroalgae for Supercapacitor Applications

“…reported carbons from cyanobacteria pyrolysis with surface area of 2184 m 2 /g, showing a specific capacitance of 222 F/g at 5 A/g in 6 M KOH. Several studies reported the hydrothermal synthesis of microalgae‐derived N‐doped carbons,,,,, exhibiting remarkable electrochemical storage performance, attributed to both their high porosity and to the N‐species inherent from the high protein fraction present in microalgae. Macroalgae, an important member of the marine biomass, has also been reported to possess interesting energy storage properties.…”