Thermoregulated Phase-Transition Synthesis of Two-Dimensional Carbon Nanoplates Rich in sp2 Carbon and Unimodal Ultramicropores for Kinetic Gas Separation.

The development of highly selective, chemically stable and moisture-resistant adsorbents is a key milestone for gas separation. Porous carbons featured with random orientation and cross-linking of turbostratic nanodomains usually have a wide distribution of micropores. Here we have developed a thermoregulated phase-transition-assisted synthesis of carbon nanoplates with more than 80 % sp2 carbon, unimodal ultramicropore and a controllable thickness. The thin structure allows oriented growth of carbon crystallites, and stacking of crystallites in nearly parallel orientation are responsible for the single size of the micropores. When used for gas separation from CH4 , carbon nanoplates exhibit high uptakes (5.2, 5.3 and 5.1 mmol g-1 ) and selectivities (7, 71 and 386) for CO2 , C2 H6 and C3 H8 under ambient conditions. The dynamic adsorption capacities are close to equilibrium uptakes of single components, further demonstrating superiority of carbon nanoplates in terms of selectivity and sorption kinetics.