N, P-doping tuning the coordination structure of carbon electrode for efficiency of copper ions capacitance deionization

Abstract

Efficient capacitive deionization (CDI) devices heavily rely on carbon-based electrodes. Hence, the structure optimization, composition, and morphology in carbon materials becomes essential for enhancing CDI performance. In this context, we have developed N, P co-doped porous carbon (PNCs) material specifically tailored CDI applications. Our findings demonstrate that the activation of N, P not only fine-tunes the electron structure of the carbon material but also enhances adsorption sites through coordination effects, leading to improved CDI performance for heavy metal ion removal. As a result, the optimized carbon material shows remarkable selectivity towards copper ions (Cu2+), with a high electrosorption capacity of approximately 159.0 mg/g@1.2 V in 500 mg/L CuCl2 solution. This study significantly contributes to the theoretical understanding and lays the foundation for CDI-based heavy metal ion recovery.