Highly porous carbon derived from hydrothermal-pyrolysis synergistic carbonization of biomass for enhanced CO2 capture

Highly porous carbon adsorbent is much desired to diminish greenhouse effect caused by CO2 emission and benefit for subsequent carbon cycle. Herein, a low-cost and environment-friendly carbonization strategy was reported for preparation of highly porous carbon derived from biomass. Such carbonization is a synergistic process with hydrothermal treatment coupled with a subsequent pyrolysis using sugarcane as biomass. The obtained hydrothermal-pyrolysis derived porous carbon (HPC) has a BET surface area of 938 m2/g, which is much higher than that of carbon produced through direct pyrolysis (PC, 528 m2/g). During the hydrothermal carbonization pretreatment, highly thermostable aromatic skeletons are formed and converted to carbon skeletons in the post-pyrolysis process, leading to formation of highly stable micropores and higher surface area. Further, HPC shows remarkable adsorption ability of CO2 (2.8 mmol/g, 25 °C, 1 bar), higher than that of PC (2.1 mmol/g). In addition, the HPC exhibits high CO2/N2 adsorption selectivity and recyclability, demonstrating its potential application in CO2 capture. This work not only gives new light for tailoring carbon materials with highly porous structure but also provides novel adsorbent for CO2 adsorption. [Display omitted] •An environment-friendly strategy was developed to prepare biomass derived highly porous carbon materials.•The obtained hydrothermal-pyrolysis carbon (HPC) showed improved porosity and enhanced CO2 adsorption capacity.•Highly thermostable skeletons formed in hydrothermal pretreatment leads to highly stable micropores and higher surface area.