Separating acetylene from carbon dioxide is highly challenging but important due to their similar physical properties and molecular dimensions. Capturing carbon dioxide from acetylene by virtue of CO2-selective absorbents can directly produce pure acetylene but rarely realized. Here, we report highly efficient electrostatically-driven CO2/C2H2 separation in an ultramicroporous cadmium-nitroprusside (Cd-NP) with compact pore space and complementary electrostatic potential well fitting for CO2, thus enabling molecular quadrupole moment recognition towards CO2 over C2H2 with significant sieving effect. This material shows high CO2/C2H2 uptake ratio of (6.0) as well as remarkable CO2/C2H2selectivity of 85 under ambient condition with modest CO2 adsorption heat (28.8 kJ mol−1), which is superior to other CO2-selective absorbents. Neutron powder diffraction experiments and molecular simulations reveal that the electrostatic potential compatibility between pore structure and CO2 allows it to be trapped in a head-on orientation towards the Cd center, whereas the diffusion of C2H2 is electrostatically forbidden. Dynamic breakthrough experiments have validated the separation performance of this compound for CO2/C2H2 separation.
Angewandte Chemie-International Edition
Porous material, gas separation, carbon dioxide, electrostatic potential, nitroprusside
, Cui, H.
, Wu, H.
, Lin, R.
, Zhou, W.
and Chen, B.
Electrostatically Driven Selective Adsorption of Carbon Dioxide over Acetylene in an Ultramicroporous Material, Angewandte Chemie-International Edition
(Accessed March 2, 2024)