Abstract
With high theoretical capacity and a safer voltage platform, Iron phosphide (FeP) as an electrode for capacitive deionization (CDI) has rare reported. In this study, nitrogen (N) and phosphorus (P)-doped polymers were impregnated with Fe(NO3)3 as the precursor material. Subsequent pyrolysis resulted in the in-situ formation of FeP nanoparticles within a carbon matrix (FeP@NC-x), characterized by a significant number of P vacancies. The optimized FeP@NC-2 electrode exhibited an exceptional specific adsorption capacity of 332.7 mg/g for Cu2+ ions in a 500 mg/L CuCl2 solution at an applied potential of 1.8 V. These remarkable results can be attributed to the well-dispersed nano-FeP and massive P vacancies within the carbon framework. This configuration expanded the electrode's conductivity and served more active sites for adsorption, reduced the diffusion path length for Cu2+ ions, and mitigated volume changes during operation. The adsorption selectivity was further elucidated through Density Functional Theory (DFT) calculations, and the adsorption-desorption mechanisms of Cu2+ ions were thoroughly investigated. This strategic approach paves the way for effective improvements in the CDI performance of transition metal phosphides and opens new avenues for advanced water purification technologies.
Original language | British English |
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Article number | 149666 |
Journal | Chemical Engineering Journal |
Volume | 484 |
DOIs | |
State | Published - 15 Mar 2024 |
Keywords
- Adsorption sites
- Capacitive deionization
- DFT
- FeP
- P vacancy