Amino-Functionalized High Entropy Lanthanide-Organic Frameworks with Dual Acid-Base Sites for Efficient CO2 Cycloaddition

A high-entropy lanthanide-based metal-organic framework (HE-LnMOF), integrating five distinct lanthanide ions (Eu 3 ⁺, Tb 3 ⁺, Gd 3 ⁺, Dy 3 ⁺, Ho 3 ⁺) and 2-aminoterephthalic acid (H 2 N-BDC) ligands, was solvothermally synthesized for efficient catalytic conversion of CO 2 into cyclic carbonates. Structural analyses confirmed the homogeneous distribution of lanthanide ions within the framework, inducing lattice distortion while preserving crystallinity. The material features uncoordinated amino groups acting as base sites and unsaturated metal centers serving as Lewis acid sites, synergistically enhancing CO 2 adsorption and activation. HE-LnMOF demonstrated superior catalytic performance for converting CO 2 into cyclic carbonates compared to monometallic Ln-MOF analogs. In situ DRIFTS studies revealed intensified carbonate intermediate signals, corroborating the role of cooperative acid-base sites in accelerating the reaction. This work demonstrates the potential of high-entropy design in MOFs to amplify catalytic efficiency and stability, offering a sustainable pathway for CO 2 utilization.