Hydride‐containing 2‐Electron Pd/Cu Superatoms as Catalysts for Efficient Electrochemical Hydrogen Evolution
Rhone P. Brocha Silalahi, Yongsung Jo, Jian‐Hong Liao, Tzu‐Hao Chiu, Eunsaem Park, Woojun Choi, Hao Liang, Samia Kahlal, Jean‐Yves Saillard, Dongil Lee, C. W. Liu
Abstract
Abstract The first hydride‐containing 2‐electron palladium/copper alloys, [PdHCu 11 {S 2 P(O i Pr) 2 } 6 (C≡CPh) 4 ] ( PdHCu 11 ) and [PdHCu 12 {S 2 P(O i Pr) 2 } 5 {S 2 PO(O i Pr)} (C≡CPh) 4 ] ( PdHCu 12 ), are synthesized from the reaction of [PdH 2 Cu 14 {S 2 P(O i Pr) 2 } 6 (C≡CPh) 6 ] ( PdH 2 Cu 14 ) with trifluoroacetic acid (TFA). X‐ray diffraction reveals that the PdHCu 11 and PdHCu 12 kernels consist of a central PdH unit encapsulated within a vertex‐missing Cu 11 cuboctahedron and complete Cu 12 cuboctahedron, respectively. DFT calculations indicate that both PdHCu 11 and PdHCu 12 can be considered as axially‐distorted 2‐electron superatoms. PdHCu 11 shows excellent HER activity, unprecedented within metal nanoclusters, with an onset potential of −0.05 V (at 10 mA cm −2 ), a Tafel slope of 40 mV dec −1 , and consistent HER activity during 1000 cycles in 0.5 M H 2 SO 4 . Our study suggests that the accessible central Pd site is the key to HER activity and may provide guidelines for correlating catalyst structures and HER activity.