Hierarchical porous carbon activated by CaCO3 from pigskin collagen for CO2 and H2 adsorption

Abstract

Porous carbon materials have drawn a great attention due to the remarkable pore structure, high specific surface area, large pore volume, excellent property of adsorption and separation. Biomass based carbon was widely concerned because of low cost, environmentally friendly and sustainability. We successfully prepared nitrogen-doped porous carbons by carbonizing collagen and CaCO3 farrago at different temperatures without any further activation. The as-prepared sample at 900 °C shows a large specific surface area of 2799 m2 g−1 and a high pore volume of 1.91 cm3 g−1. And the sample at 600 °C shows a relatively high nitrogen content and a large amount of narrow micropores (<0.7 nm), which endows this sample moderate CO2 adsorption capacity (1.27 mmol g−1 at 298 K under 0.15 bar, 4.4 mmol g−1 at 298 K under 1 bar and 5.3 mmol g−1 at 273 K under 1 bar). The maximum hydrogen uptake of 2.49 wt% at 77 K under 1.13 bar can be observed when carbonization temperature goes to 800 °C. The CO2 uptake is influenced by narrow micropore (<0.7 nm) volume, meanwhile CO2 uptake is improved by high nitrogen content. And specific surface area and total pore volume make important roles for hydrogen uptake. Small mesopores of size between 2 and 3 nm also contribute to hydrogen adsorption. These results prove that collagen based porous carbon is a desirable candidate for industrially CO2 capture and H2 storage.