N-doping strategy for enhancing the adsorption performance of Ti2CT2 MXene for Sr ion

Radionuclides, such as strontium (Sr), are hazardous radioactive isotopes commonly found in nuclear waste, posing serious environmental and health risks due to their long half-lives and ability to bioaccumulate. Inspired by the electronic modification effect, this study theoretically predicts that doping can significantly enhance the adsorptive performance of MXenes for radionuclides. Specifically, we employed comprehensive first-principles simulations to investigate the impact of nitrogen (N) doping on the adsorption behavior of Ti2CT2 (T = O, F, OH) MXenes for Sr ions, focusing on surface N doping and C-site N doping as effective strategies to improve adsorption. The results confirmed that both types of N doping are beneficial for the adsorption performance of Ti2CT2, and the adsorption strengths of Ti2CT2 with surface N doping are significantly enhanced. This was analyzed and attributed to the ability of N doping to enhance the charge transfer between the Ti2CT2 surface and Sr ions, thus enhancing the adsorption properties. By elucidating the N doping mechanisms, this study is expected to provide theoretical guidance for the design of high-performance MXene materials in radionuclides remediation applications.