Synergistic Carbon Nitride‐Coated Bismuth Composites for Sustainable Water Purification

The development of high‐performance electrodes is crucial for advancing capacitive deionization (CDI) technology. This work presents a rationally designed bismuth trioxide/graphitic carbon nitride (BO‐CN‐20) composite anode that achieves a high salt adsorption capacity of 32.63 mg g −1 and good initial cycling performance (91% retention after 10 cycles). Combined experimental and density functional theory (DFT) studies reveal that the enhanced performance originates from a synergistic effect between the two components. This synergy involves efficient Cl − storage via reversible redox reactions on bismuth trioxide (Bi 2 O 3 ), coupled with the structural integrity ensured by the graphitic carbon nitride (g‐C 3 N 4 ) framework. The composite exhibits an optimal Cl − adsorption energy, which facilitates both high capture and facile release of ions. This study not only demonstrates a high‐performance CDI electrode but also offers valuable insights into the design of synergistic composite materials for advanced desalination.