Porous N, P co-doping Ti3C2Tx MXene for high-performance capacitive deionization

The emerging energy-saving and environmentally friendly capacitive deionization (CDI) technology has attracted more and more attention. However, it remains a great challenge to develop CDI electrode materials with excellent comprehensive properties. Herein, the porous N, P co-doping Ti₃C₂T_x MXene (N, P-Ti₃C₂T_x) was prepared successfully by combining simple flocculation with an annealing process. Benefitting from the synergistic effect of the combination of porous structure and co-doping of N and P heteroatoms, the N, P-Ti₃C₂T_x exhibits substantial specific surface area, which provides more surface bounding active sites for electrochemical reactions, thus assisting to boost the CDI performance. As a result, the N, P-Ti₃C₂T_x exhibited an admirable salt (Na⁺) adsorption capacity of 53.3 mg g⁻¹ and exceptional recycling property. Impressively, the N, P-Ti₃C₂T_x also exhibited superior desalination performance of Pb²⁺, characterized by an exceptionally high desalination capacity of up to 168.2 mg g⁻¹ at 1.2 V, and the corresponding desalination rate reached 0.047 mg g⁻¹ s⁻¹. Additionally, the deionization mechanism involved was elucidated through a series of characterizations. This work will furnish an effective avenue for the innovative design of MXene-based electrode materials toward high-performance CDI.