Hydride-Containing Pt-doped Cu-rich Nanoclusters: Synthesis, Structure, and Electrocatalytic Hydrogen Evolution.

A structurally precise hydride-containing Pt-doped Cu-rich nanocluster [PtH 2 Cu 14 {S 2 P(O i Pr) 2 } 6 (CCPh) 6 ] (1) has been synthesized. It consists of a bicapped icosahedral Cu 14 cage that encapsulates a linear PtH 2 unit. Upon the addition of two equivalents of CF 3 COOH to 1, two hydrido clusters are isolated. These clusters are [PtHCu 11 {S 2 P(O i Pr) 2 } 6 (CCPh) 4 ] (2), which is a vertex-missing Cu 11 cuboctahedron encaging a PtH moiety, and [PtH 2 Cu 11 {S 2 P(O i Pr) 2 } 6 (CCPh) 3 ] (3), a distorted 3,3,4,4,4-pentacapped trigonal prismatic Cu 11 cage enclosing a PtH 2 unit. The electronic structure of 2, analyzed by Density Functional Theory, is a 2e superatom. The electrocatalytic activities of 1-3 for hydrogen evolution reaction (HER) were compared. Notably, Cluster 2 exhibited an exceptionally excellent HER activity within metal nanoclusters, with an onset potential of -0.03 V (at 10 mA cm -2 ), a Tafel slope of 39 mV dec -1 , and consistent HER activity throughout 3000 cycles in 0.5 M H 2 SO 4 . Our study suggests that the accessible central Pt site plays a crucial role in the remarkable HER activity and may provide valuable insights for establishing correlations between catalyst structure and HER activity.