Synthesis of a novel carbon microsphere with multi-cavity mesoporous structure for CO2 adsorption.

Porous carbon microspheres are widely regarded as a superior CO2 adsorbent due to their exceptional efficiency and affordability. However, better adsorption performance is very attractive for porous carbon microspheres. And modification of the pore structure is one of the effective strategies. In this study, multi-cavity mesoporous carbon microspheres were successfully synthesized by the synergistic method of soft and hard templates, during which a phenolic resin with superior thermal stability was employed as the carbon precursor and a mixture of silica sol and F108 as the mesoporous template. Carbon microspheres with multi-cavity mesoporous structures were prepared, and all the samples showed highly even mesopores, with diameters around 12 nm. The diameter of these microspheres decreased from 396.8 nm to about 182.5 nm with the increase of silica sol. After CO2 activation, these novel carbon microspheres (APCF0.5-S1.75) demonstrated high specific surface area (983.3 m2/g) and remarkable CO2 uptake of 4.93 mmol/g at 0 °C and1 bar. This could be attributed to the unique multi-cavity structure, which offers uniform mesoporous pore channels, minimal CO2 transport of and a greater number of active sites for CO2 adsorption.