Topological Duality: Constructing High-Nuclearity Metal Clusters with Unleashed Active Sites for Efficient and...

Precise control of active sites with atomic resolution in metal nanoclusters (MNCs) presents a promising avenue for catalyst engineering towards CO₂ electroreduction. However, effective strategies to construct high-nuclearity MNCs while balancing catalytic stability and active-site exposure remain scarce. Herein, we propose a "topological-duality-driven" strategy to construct a high-nuclearity Cu₂₄Ag₅₄ nanocluster, featuring an octahedral {Cu₂₄} shell and a double-truncated cubic {Ag₅₄} core with exposed {Ag₃} vertices on {111} facets. Notably, the double-truncated cubic is a previously unexplored concave polyhedron with over twice the number of {111} facets compared to conventional structures. As a catalyst for CO₂ electroreduction, Cu₂₄Ag₅₄ delivers exceptional performance including a Faradaic efficiency for CO of ∼98%, catalytic stability exceeding 100 h, and current densities up to 750 mA cm^-2 (total current 3 A), ranking among the highest values of the reported MNCs. Dedicated studies show the nested structure and increased electron delocalization underpin the catalyst durability. The facilitated electron transfer from Ag to the key intermediate *COOH and electron delocalization effect significantly reduce the energy barrier for *COOH formation by 50%. This work provides a new perspective on the potential of topological geometries in designing high-nuclearity MNCs for highly efficient and robust CO₂ electroreduction at industrial current density.