Electropolymerization of Metal Clusters Establishing a Versatile Platform for Enhanced Catalysis Performance

Abstract

Atomically precise metal clusters are attractive as highly efficient catalysts, but suffer from continuous efficiency deactivation in the catalytic process. Here, we report the development of an efficient strategy that enhances catalytic performance by electropolymerization (EP) of metal clusters into hybrid materials. Based on carbazole ligand protection, three polymerized metal‐cluster hybrid materials, namely Poly‐Cu14cba, Poly‐Cu6Au6cbz and Poly‐Cu6Ag4cbz, were prepared. Compared with isolated metal clusters, metal clusters immobilizing on a biscarbazole network after EP significantly improved their electron‐transfer ability and long‐term recyclability, resulting in higher catalytic performance. As a proof‐of‐concept, Poly‐Cu14cba was evaluated as an electrocatalyst for reducing nitrate (NO3−) to ammonia (NH3), which exhibited ≈4‐fold NH3 yield rate and ≈2‐fold Faraday efficiency enhancement compared to that of Cu14cba with good durability. Similarly, Poly‐Cu6Au6cbz showed 10 times higher photocatalytic efficiency towards chemical warfare simulants degradation than the cluster counterpart.

N-Heterocyclic Carbene-Stabilized Gold Nanoclusters with Organometallic Motifs for Promoting Catalysis

“…Together with the well-defined structures that can be determined by X-ray crystallography, the presence of both organic ligands and metal–metal bonds makes ligand-protected atomically precise metal nanoclusters (NCs) an ideal model catalyst system to bridge the gap between organometallic catalysts and metal nanocatalysts. − For example, the surface coordination structures of ligands, e.g., phosphine, thiolate, alkynyl, and N-heterocyclic carbene (NHC), on metal NCs have now been well demonstrated. ,, Moreover, the molecular understanding of their catalytic mechanism is expected to provide insights on how surface ligands and metal–metal interactions interplay together to determine the catalytic performance of metal catalysts. − Among them, the recently emerging Au NCs protected by NHCs are expected to serve as an ideal candidate for catalytic mechanism investigations due to their outstanding stability but possible presence of exposure metal sites. − On the other hand, homogeneous gold catalysts with NHC-Au-X structures have been widely applied in chemical transformations, including, but not limited to, the activation and transformation of alkynes, alkenes, and allenes . While the NHC ligands prevent the complex decomposition, and control electronic and steric effects for modulating catalysis, the anionic (X) ligands help balance the charge and often get involved in catalytic cycles by ligand exchange with substrates .…”