Tuning MOF CO₂ Adsorption Properties via Cation Exchange

The pore volume and BET surface area of bio-MOF-1 (a), Zn(8)(ad)(4)(BPDC)(6)O.2Me(2)NH(2), is systematically modified via postsynthetic cation exchange with either tetramethylammonium, tetraethylammonium, or tetrabutylammonium cations to yield Zn(8)(ad)(4)(BPDC)(6)O.2Me(4)N (b), Zn(8)(ad)(4)(BPDC)(6)O.2Et(4)N (c), and Zn(8)(ad)(4)(BPDC)(6)O.2Bu(4)N (d), respectively. The impact that pore volume and BET surface area have on CO(2) capacity is evaluated, and it is found that materials with intermediate porosity (b and c) have the largest CO(2) capacities under the conditions studied.