Electrically Heatable Graphene Aerogels as Nanoparticle Supports in Adsorptive Desulfurization and High‐Pressure CO₂ Capture

Abstract

Reduced-graphene-oxide (rGO) aerogels provide highly stabilising, multifunctional, porous supports for hydrotalcite-derived nanoparticles, such as MgAl-mixed-metal-oxides (MgAl-MMO), in two commercially important sorption applications. Aerogel-supported MgAl-MMO nanoparticles show remarkable enhancements in adsorptive desulfurization performance compared to unsupported nanoparticle powders, including substantial increases in organosulfur uptake capacity (>100% increase), sorption kinetics (>30-fold), and nanoparticle regeneration stability (>3 times). Enhancements in organosulfur capacity are also observed for aerogelsupported NiAl-and CuAl-metal-nanoparticles. Importantly, the electrical conductivity of the rGO aerogel network adds completely new functionality by enabling accurate and stable nanoparticle temperature control via direct electrical heating of the graphitic support. Support-mediated resistive heating allows for thermal nanoparticle recycling at much faster heating rates (>700 °C•min −1) and substantially reduced energy consumption, compared to conventional, external heating. For the first time, the CO 2 adsorption performance of MgAl-MMO/rGO hybrid aerogels is assessed under elevated-temperature and high-CO 2-pressure conditions relevant for pre-combustion carbon capture and hydrogen generation technologies. The total CO 2 capacity of the aerogel-supported MgAl-MMO nanoparticles is more than double that of the unsupported nanoparticles and reaches 2.36 mmol•CO 2 g −1 ads (at p CO2 = 8 bar, T = 300 °C), outperforming other high-pressure CO 2 adsorbents.

Two-dimensional material-based functional aerogels for treating hazards in the environment: synthesis, functional tailoring, applications, and sustainability analysis

“…It has been proved that graphene aerogels combined with NB compounds, 147 chitosan, 148 hydrotalcite derived NPs, 149 and ionic liquids 150 can effectively capture CO 2 . As shown in Fig.…”

“…8a and b, Xia et al synthesized MgAl-mixed metal oxide/GO composite aerogel (MgAl-MMO/RGO composite aerogel) which can efficiently adsorb CO 2 through a simple three-step manufacturing process. 149 In the first step, LDH are attached to GO under the attraction of electrostatic interaction, and then LDH/ GO hydrogels are formed with the help of molds and polymer additives. In the second step, LDH/GO hydrogel is transformed into LDH/GO aerogel with macroporous structure by unidirectional freezing and freeze-drying.…”

Light-induced levitation of ultralight carbon aerogels via temperature control

“…Aerogels 1 and metallic microlattices 2 , 3 are typical lightweight materials with large specific surface areas. As a result, they are attracting attention as structural materials as well as adsorbents 4 , 5 , energy storage materials 6 , catalyst support materials 7 , and thermal insulators 8 . To the best of our knowledge, the lightest material reported thus far is a ceramic aerogel with a density of 0.10 mg cm −3 9 .…”

Tuning the Electrical and Solar Thermal Heating Efficiencies of Nanocarbon Aerogels

“…direct resistive Joule-heating has been employed to thermally regenerate functional graphene and CNT aerogels at temperatures between 100-400 °C for highly sensitive gas sensing 6 and adsorptive fuel desulfurization. 3,4 Meanwhile, Joule-heating was also successfully employed for precise temperature control of Ag/Co3O4/Carbon hybrid aerogel catalysts, used for efficient catalytic formaldehyde oxidation at 90 o C. 15 Direct electro-thermal heating of interconnected 3D nanocarbon networks has also been exploited for polymer curing [16][17][18] and for the detection of structural damage in polymer nanocomposites through thermal IR imaging. 19 Joule-heating has also been proven as an energy efficient approach to induce heating in graphene-wrapped polymeric sponges in order to thermally enhance their performance as crude-oil clean-up agents.…”

“…Nanocarbon aerogels have been widely explored as high-performance functional materials in sorption, catalysis, fuel purification, , energy storage, and sensing . Recently, nanocarbon-based aerogels have also shown great promise for desalination and solar steam evaporation applications, , which are important for the development of new clean water technologies.…”