Metal heteroatom (Mg, Cu and Co) and porous carbon co-doped MIL-101 composites with superior acetone capture capacity

Abstract

The development of highly active and stable adsorbents for volatile organic compounds (VOCs) capture is an efficient solution to address global problems in atmospheric pollution and environmental health. Herein, a metal–organic framework derived adsorbent consisting of metal heteroatom (Mg, Cu and Co) and porous carbon supported on MIL-101 framework is designed to enable high affinity for adsorbing acetone. The doped metal heteroatoms are homogeneously dispersed in the MIL-101/PC octahedron. The modification of doped metal heteroatoms improves the acetone adsorption capacity of the MIL-101/PC composite at low relative pressure. Importantly, the optimized 20%Mg@MIL-101/PC composite not only shows higher surface area (3838 m2 g−1) and pore volume (2.24 mL g−1) than MIL-101/PC, but also creates stronger active adsorption sites for acetone. As a consequence, the acetone adsorption capacity of 20%Mg@MIL-101/PC reaches 1309 mg g−1 at 288 K and 18 bar, and the saturated adsorption capacity decreases by only 12% over 10 adsorption–desorption consecutive cycles. Consequently, quantum chemistry calculation method is performed to better understand the microscopic adsorption behavior of acetone. The results of density functional theory (DFT) calculation show that the introduction of Mg can significantly improve the dipole moment of MIL-101 core and reduce its gap band energy, thus enhancing the electrostatic interaction with acetone molecule.