Kernel Geometry Transformation by Controlled S Incorporation in Cu 14 Nanocluster and Its Impact on Electrocatalysis

ABSTRACT Cu nanoclusters have recently enabled the understanding of active sites and structural factors determining the electrocatalysis performance due to their atomic precision. However, the influence of structure geometry has so far remained elusive to Cu‐nanoclusters‐catalyzed electroreduction of CO 2 . Here, we reported the controlled S incorporation based on the reductant dosage, achieving the geometry transformation of the Cu 8 kernel in the Cu 14 nanocluster while retaining the composition, outer motifs, and Cu valence state. Cu 14 with a parallelepiped kernel exhibits a distinct selectivity toward CH 4 (FE ∼51%), which contrasts with Cu 14 ‐S containing a cubic kernel (mainly C 2+ products, FE ∼33.8%). The electronic structures of Cu 14 nanoclusters are further revealed to be modulated by kernel geometry, altering the binding modes or energetics of the intermediates, as evidenced by in situ spectroscopy and theoretical calculation.