Design of Highly Nitrogen-Doped, Two-Dimensional Hierarchical Porous Carbons with Superior Performance for Selective Capture of CO₂ and SO₂

Nitrogen-doped porous carbons show great application potentials in the areas of heterogeneous catalysis, adsorption, and separation. Nevertheless, the design and synthesis of nitrogen-doped porous carbons with controllable structural characteristics (e.g., hierarchical porosity and effective nitrogen sites) were usually complex and high cost. We demonstrate here a class of 2D, nitrogen-doped hierarchical porous carbons (GC-xs) synthesized from one-step, solvent-free carbonization of the mixture containing glucose biomass and g-C₃N₄. The resulting GC-xs possess large BET surface areas (474–748 m²/g), abundant 2D hierarchical porosity, and high contents of nitrogen sites (11.6–16.3 wt %) with tunable pyridinic characteristics (∼62.6%). The developed GC-xs were demonstrated to act as high-efficient adsorbents for the selective capture of acid gases such as SO₂ and CO₂, which exhibit impressive capacities for selective capture of CO₂ (∼3.1 mmol/g, at 0 °C, 1.0 bar) and SO₂ (∼11.7 mmol/g at 25 °C, 1.0 bar). The GC-xs also exhibit exceptionally high IAST selectivity for CO₂/N₂ (0.10/0.90) at 1 bar (340–490 at 0 °C and 423–489 at 25 °C) and SO₂/N₂ (0.10/0.90) at 1 bar (1431–1601 at 25 °C and 1502–1803 at 50 °C) in comparison with many reported porous adsorbents. The preparation of GC-xs provides a new concept to the design of 2D, highly nitrogen-doped porous carbons with high performance and enhanced selectivity for the capture of CO₂ and SO₂ from flue gas.