Mechanochemical-Assisted Defect Engineering: Enhanced Post-Synthetic Metal Exchange in MOFs

Abstract

The post-synthesis metal exchange (PSME) strategy receives substantial attention in the construction of heterometallic mental-organic frameworks (MOFs). However, traditional PSME methods encounter challenges such as prolonged solvothermal incubation and difficulties in introducing secondary metal elements. Thus, developing a rapid, sustainable, and scaled-up PSME approach for MOFs is essential. Herein, we present a mechanochemical-assisted defect engineering strategy that accelerates the PSME process (mechano-PSME). Characterization techniques demonstrate that this strategy swiftly overcomes the energy barriers of the parent MOFs, resulting in the formation of an abundance of defects. This creates an optimal environment for incorporating heterometallics, thus facilitating rapid, batch PSME of MOFs. The experimental results clearly validate the effectiveness of mechano-PSME in producing bimetallic Zr/Hf-based UiO-66, a process challenging to achieve under solvothermal conditions. Additionally, the Zr/Hf-based UiO-66 exhibits improved acidic functionality and exceptional catalytic efficiency in the esterification of levulinic acid. This research paves the way for the sustainable development of functional materials and outlines an ambitious blueprint for innovating multifunctional materials.