In Situ Synthesis of Bismuth Nanoclusters within Carbon Nano‐Bundles from Metal–Organic Framework for Chloride‐Driven Electrochemical Deionization

Abstract Ultrasmall metal nanoclusters (MNCs, <3 nm) have emerged as a novel class of functional nanomaterials. Different from the prosperous development of noble MNCs, the fabrication of non‐noble MNCs remains a major challenge, which greatly curtails the advance of relevant application fields. Herein the authors put forward an in situ synthesis strategy of bismuth nanoclusters (Bi NCs) within carbon nano‐bundles (Bi NCs@CNBs) by simply carbonizing the Bi‐containing metal–organic framework (Bi‐MOF), and deploy it as a Cl − capturing electrode for electrochemical deionization (EDI) towards the relief of global freshwater scarcity. Of note, as a “killing two birds with one stone” strategy, the Bi‐MOF not only makes the in situ formation of Bi NCs possible but also provides a reinforcing “carbon shell” for better electronic conductivity and structural stability. As a result, the Bi NCs@CNB‐based EDI system displays ultrafast desalination (0.52 mg g −1 s −1 ) with outstanding cycling stability, which is beneficial from the ultrasmall size of the electrode material and cannot be achieved by large‐sized Bi nanoparticle‐based system. This work is interesting because it unprecedentedly introduces ultrasmall MNCs into EDI to manipulate the surface‐controlled Cl − storage for ultrafast EDI, boosting the advances of both non‐noble MNCs and their application in EDI.