Constructing a carboxyl-rich angstrom-level trap in a metal-organic framework for the selective capture of lithium.

A metal-organic-framework-based ion trap was designed via tailoring linker functionality as well as free -COOH density. The mixed-linker UiO-66-H 2 /H 4 exhibits higher adsorption for Li + ions than H 4 -free UiO-66-H 2 because the H 4 linker provides an additional -COOH group in the local region.