Atomically Precise Silver Nanoclusters for Electrochemical Uranium Extraction

Abstract Inorganic nanomaterials have demonstrated significant potential in electrochemical uranium extraction (EUE) from seawater. However, it is difficult to reveal the structure−activity relationship at the atomic level due to its polydispersity and heterogeneity. Atomically precise metal nanoclusters provide an ideal platform to state the extraction mechanism. In this work, we use atomically precise Ag29(BDT)12(TPP)4 nanoclusters (Ag29 NCs, BDT = 1,3-benzenedithiol and TPP = triphenylphosphine) as electrode materials for EUE. The intrinsic properties of Ag29 NCs might endow them with a strong interaction toward the uranyl ion. The electrochemical results demonstrate that Ag29 NCs exhibit extraction capacities of 1544.1 mg/g in ultrapure water with 100 ppm UO2(NO3)2 and 1350.9 mg/g in spiked seawater, which is superior to most previously reported electrode materials. Moreover, Ag29 NCs display excellent recycling, ion selectivity, and structural stability. Theoretical calculations reveal that Ag29 NCs can chemically adsorb UO22+ via Ag−U and S−U bonds, generating strong interfacial electronic coupling. In addition, the nanoclusters can reduce uranyl ions with a low reaction energy barrier. This work provides insights into designing high-performance uranium extraction materials and advances the practical application of nanocluster catalysts in nuclear fuel technologies.