High CO 2 /CH 4 Selectivity of a Flexible Copper(II) Porous Coordination Polymer under Humid Conditions

The development of highly efficient CO 2 separation materials is very important for environmental preservation and energy conservation. Crystalline porous coordination polymers (PCPs)/metal–organic frameworks are one of a number of promising types of porous materials for CO 2 separation because of their controllable pore size, shape and surface function. Simultaneously, the unique structural flexibility of PCPs affords both high CO 2 selectivity and inexpensive regeneration. However, this family of materials suffers from the coexistence of water that destroys the framework of PCPs and its adsorption in the pores is greater than that of CO 2 , which results in a deterioration in CO 2 ‐separation performance. Herein, a flexible and hydrophobic Cu II PCP that is stable towards water has been designed and synthesised. This PCP has extremely high adsorption selectivity for CO 2 over CH 4 , derived from its structural flexibility. Furthermore, the obtained water‐tolerant flexible PCP, under CO 2 /CH 4 mixed‐gas conditions, exhibits highly selective CO 2 adsorption over CH 4 , even in the presence of water.