Li Liang-Jun, Luo Yu-Ting, Tian Yi-Qi, Wang Pu, Yi Xiao-Yi, Yan Jun, Pei Yong, Liu Chao
College of Chemistry and Chemical Engineering, Central South University, Changsha 410083, P. R. China.
Department of Chemistry, Key Laboratory of Environmentally Friendly Chemistry and Applications of Ministry of Education, Xiangtan University, Xiangtan 411100, P. R. China.
Inorg Chem. 2023 Sep 4;62(35):14377-14384. doi: 10.1021/acs.inorgchem.3c02083. Epub 2023 Aug 24.
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 [Ag(TC4A)(PrS)] nanocluster that demonstrates both high stability and catalytic activity. The nanocluster features a metallic core, Ag, consisting of two Ag triangles and one Ag square, shielded by four {Ag@(TC4A)} staple motifs. Based on DFT calculations, the Ag metallic kernel can be viewed as a trimer comprising 2-electron superatomic units, exhibiting a valence electron structure similar to that of the Be molecule. Notably, this is the first crystallographic evidence of the trimerization of 2-electron superatomic units. can reduce CO 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 Ag polymer {[HAg(TC4A)(PrS)]} (), with the composition similar to . DFT calculations elucidated the catalytic mechanism to clarify the contrasting catalytic performances of the and polymers and disclosed that the intrinsically higher activity of may be due to the greater stability of the dual adsorption mode of the *COOH intermediate on the metallic core.
纳米团簇催化剂在稳定性和催化活性之间取得恰当平衡方面面临重大挑战。在此，我们展示了一种由硫代杯[4]芳烃保护的6电子[Ag(TC4A)(PrS)]纳米团簇，它兼具高稳定性和催化活性。该纳米团簇具有一个金属核，即由两个银三角形和一个银正方形组成的Ag，被四个{Ag@(TC4A)}订书钉状基序所屏蔽。基于密度泛函理论（DFT）计算，Ag金属核可被视为由2电子超原子单元组成的三聚体，呈现出与Be分子相似的价电子结构。值得注意的是，这是2电子超原子单元三聚化的首个晶体学证据。在相对于可逆氢电极（RHE）为 -0.9 V时，其能将CO还原为CO，法拉第效率为93.4%，并具有出色的长期稳定性。其催化活性远优于链状Ag聚合物{[HAg(TC4A)(PrS)]}（），二者组成相似。DFT计算阐明了催化机理，以厘清 和 聚合物截然不同的催化性能，并揭示出 本质上更高的活性可能归因于*COOH中间体在金属核上双重吸附模式具有更高的稳定性。
