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

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.