Microporous carbon nanoflakes derived from biomass cork waste for CO2 capture

Porous structure design is considered to be a promising strategy for the development of effective sorbents for CO2 capture. Herein, a series of carbon nanoflakes with large surface area (up to 2380 m(2)/g) and high micropore volume (up to 0.896 m(3)/g) were synthesized from a renewable precursor, cork dust waste, to capture CO2 at atmospheric pressure. The nanoflakes exhibited superior CO2 uptake performance at 1 bar with the maximum capacity of 7.82 and 4.27 mmol/g at 0 and 25 degrees C, respectively, in sharp contrast to previously reported porous carbon materials. The existence of large numbers of narrow micropores with the pore width less than 0.86 nmand 0.70 nm play a critical role in the CO2 uptake at 0 and 25 degrees C, respectively. Moreover, the CNFs exhibited good recyclability and high selectivity for CO2 uptake from the mixture of CO2 and N-2. By taking advantage of the unique hollow honeycomb cell, the three-layered cell wall structure, as well as the unique chemical composition of a cork precursor, such delicate microporous carbon nanoflakes were able to be achieved by simple thermal pretreatment combined with chemical activation. This bioinspired precursor-synthesis route poses a great potential for the facile production of porous carbons for a variety of diverse applications including CO2 capture. (C) 2020 Elsevier B.V. All rights reserved.