Biomass-Based N-Rich Porous Carbon Materials for CO 2 Capture and in-situ Conversion.

Capturing CO 2 and subsequently converting into valuable chemicals has attracted extensive attention. Herein, a series of biomass-based N-rich porous carbon materials with high specific surface area and pore volume were prepared using biomass waste soybean dregs as precursors. The nitrogen content was up to 4 % with different forms in the carbon skeleton such as pyridine-N, pyrrole-N. The synergistic effect of ultra-micropore (pore size <0.7 nm) and N-containing groups endowed the materials with a high CO 2 adsorption capacity, reaching 6.3 and 3.6 mmol g -1 at 0 and 25 °C under atmospheric pressure, respectively. In addition, the sufficient interaction between N-containing groups and CO 2 was demonstrated by solid-state nuclear magnetic resonance spectroscopy, and the captured CO 2 was possibly activated in the form of carbamate, which is conducive to subsequent conversion. Therefore, the supported catalyst with the as-synthetic porous carbon material as the carrier and Zn II as catalytic sites was prepared and successfully applied for carboxylative cyclization of propargylic amine with CO 2 to afford the 3-benzyl-5-methyleneoxazolidin-2-one. The results showed that CO 2 capture and in-situ conversion work effectively to produce highly value-added chemicals. In this process, the captured CO 2 could be activated and fixed into chemicals in mild conditions. More importantly, the energy consumption in CO 2 desorption and adsorbent regeneration could be avoided. The valorization of both solid waste and CO 2 to valuable chemicals provides an elegant strategy of killing three birds with one stone.