High‐Entropy Metal‐Organic Frameworks (HEMOFs): A New Frontier in Materials Design for CO2 Utilization

High‐entropy materials (HEMs) emerged as promising candidates for a diverse array of chemical transformations, including CO2 utilization. However, traditional HEMs catalysts are nonporous, limiting their activity to surface sites. Designing HEMs with intrinsic porosity can open the door toward enhanced reactivity while maintaining the many benefits of high configurational entropy. Here, a synergistic experimental, analytical, and theoretical approach to design the first high‐entropy metal‐organic frameworks (HEMOFs) derived from polynuclear metal clusters is implemented, a novel class of porous HEMs that is highly active for CO2 fixation under mild conditions and short reaction times, outperforming existing heterogeneous catalysts. HEMOFs with up to 15 distinct metals are synthesized (the highest number of metals ever incorporated into a single MOF) and, for the first time, homogenous metal mixing within individual clusters is directly observed via high‐resolution scanning transmission electron microscopy. Importantly, density functional theory studies provide unprecedented insight into the electronic structures of HEMOFs, demonstrating that the density of states in heterometallic clusters is highly sensitive to metal composition. This work dramatically advances HEMOF materials design, paving the way for further exploration of HEMs and offers new avenues for the development of multifunctional materials with tailored properties for a wide range of applications. High‐entropy metal‐organic frameworks (HEMOFs) are synthesized with up to 15 distinct metals, representing an unprecedented level of complexity for MOFs. A suite of complementary characterization techniques and density functional theory calculations unravel the metal distributions in the materials; well‐mixed heterometallic clusters are directly visualized by high resolution microscopy tools. The HEMOFs are highly active for CO2 epoxidation under mild conditions.