Waste Biomass Based Carbon Aerogels Prepared by Hydrothermal-carbonization and Their Ethanol Cracking Performance for H2 Production

Biomass occupies a significant proportion of municipal solid waste. For the high-value processing of waste biomass, a hydrothermal-carbonization method was chosen because of the advantages of effective and mild conditions. Four typical types of waste biomass (banana peel, mangosteen peel, orange peel, and pomelo peel) were used in this work to prepare high-value carbon aerogels (CA) via hydrothermal-carbonization treatment for cracking ethanol. Four kinds of CA all had good performances in the ethanol cracking reaction and improved the yield of H2 from 21 wt% to about 40 wt%. The banana peel-based carbon aerogel (BPCA) showed the best performance in the reaction; it cracked ethanol and obtained 41.86 wt% of H2. The mechanism of ethanol cracking by CA was revealed: On one hand, the self-cracking of ethanol was improved due to the extension of residence time, which benefited from the abundant pores in CA. On the other hand, the heterogeneous reaction occurred on the surface of CA where the inorganic components, mainly Ca, Mg, and K, can promote the bond-breaking and reorganization in ethanol. The CO2 in byproducts was also fixed by Ca and Mg, improving the positive cracking reaction.

Enhanced capacitive performance by improving the graphitized structure in carbon aerogel microspheres

Herein, good electrical conductivity and high specific surface area carbon aerogel (CA) microspheres were synthesized by a facile and economical route using a high temperature carbonization and CO₂ activation method. The electroconductive graphitized structure of the CA microspheres could be easily improved by increasing the carbonization temperature. Then the CA microspheres were activated with CO₂ to increase the specific surface area of the electrode material for electric double layer capacitors (EDLC). The sample carbonized at 1500 °C for 0.5 h and CO₂ activated at 950 °C for 8 h showed an acceptable specific surface area and excellent cycle performance and rate capability for EDLC: 98% of the initial value of the capacitance was retained after 10 000 cycles, a specific capacitance of 121 F g⁻¹ at 0.2 A g⁻¹ and 101 F g⁻¹ at 2 A g⁻¹.

Carbon aerogels (CAs) microspheres with good electrical conductivity and high specific surface area were synthesized by high temperature carbonization and CO₂ activation method, which exhibit an enhanced capacitive performance in supercapacitors.

Interplay between porous texture and surface-active sites for efficient oxygen reduction reactions in N-inherited carbon

Nitrogen-doped porous carbon materials have excellent ORR activities due to their synergistic effects caused by the electron-accepting ability of the adjacent sp² bonded carbon atoms leading to the redistribution of charge density.