Enhancement of interfacial interaction between carbon and silver nanoparticles through co-doping with nitrogen and phosphorus

The capacitive deionization technology has demonstrated its efficacy in removing chlorine-containing contaminants from water. However, the long-term and selective removal of Cl− remains a significant challenge. We present the synthesis of nitrogen‑phosphorus co-doped carbon composites embedded with silver-metal particles by incorporating N and P heteroatoms, which serve as effective anchoring sites for metallic Ag. The design of the electrode material ultimately enhances the electrochemical stability of silver by facilitating strong interactions between nitrogen and phosphorus with the silver and carbon substrates, respectively, forming stable chemical bonds. The electrode material exhibited excellent dechlorination performance, with a selectivity factor (Cl− versus SO42−) of up to 83.4 for Cl− in wastewater in a mixed solution and an adsorption capacity of 99.2 mg·g−1 for Cl−. Additionally, the silver-based selective dechlorination electrode achieved a desalination capacity of 77.7 mg·g−1 for Cl− in a single system and demonstrated remarkable stability over 100 cycles, retaining 93.99 % of its capacity. The present study demonstrates that introducing nitrogen and phosphorus can significantly enhance the cyclic stability of silver‑carbon electrodes, thereby facilitating the sustainable treatment of chlorinated wastewater. [Display omitted] •The addition of nitrogen and phosphorus increases the binding energy between silver and carbon, enhancing electrochemical stability.•The selectivity coefficient of the silver carbon electrode for Cl- was determined to be 83.4, while showing an impressive adsorption capacity of 99.2 mg·g-1.•Ag@CNP composite electrode material exhibited Cl− behavior for over 100 cycles in the CDI system.•Heteroatoms stabilize the connection between metallic silver and surface carbon to maintain the electrochemical environmental reaction cycling performance.