Unveiling the Remarkable Stability and Catalytic Activity of a 6‑Electron Superatomic Ag30 Nanocluster for CO2 Electroreduction

• Published in: Inorganic chemistry 2023-09, Vol.62 (35), p.14377-14384
• Main Authors: Li, Liang-Jun, Luo, Yu-Ting, Tian, Yi-Qi, Wang, Pu, Yi, Xiao-Yi, Yan, Jun, Pei, Yong, Liu, Chao
• Format: Article
• Language: English
• ISSN: 0020-1669; 1520-510X
• DOI: 10.1021/acs.inorgchem.3c02083

Nanocluster catalysts face a significant challenge in striking the right balance between stability and catalytic activity. Here, we present a thiacalix[4]­arene-protected 6-electron [Ag30(TC4A)4(iPrS)8] nanocluster that demonstrates both high stability and catalytic activity. The Ag 30 nanocluster features a metallic core, Ag10 4+, consisting of two Ag3 triangles and one Ag4 square, shielded by four {Ag5@(TC4A)4} staple motifs. Based on DFT calculations, the Ag10 4+ metallic kernel can be viewed as a trimer comprising 2-electron superatomic units, exhibiting a valence electron structure similar to that of the Be3 molecule. Notably, this is the first crystallographic evidence of the trimerization of 2-electron superatomic units. Ag 30 can reduce CO2 into CO with a Faraday efficiency of 93.4% at −0.9 V versus RHE along with excellent long-term stability. Its catalytic activity is far superior to that of the chain-like AgI polymer ∞ 1{[H2Ag5(TC4A)­(iPrS)3]} (∞ 1 Ag n ), with the composition similar to Ag 30 . DFT calculations elucidated the catalytic mechanism to clarify the contrasting catalytic performances of the Ag 30 and ∞ 1 Ag n polymers and disclosed that the intrinsically higher activity of Ag 30 may be due to the greater stability of the dual adsorption mode of the *COOH intermediate on the metallic core.