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 (Bi₂O₃), coupled with the structural integrity ensured by the graphitic carbon nitride (g-C₃N₄) 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.