N-Functionalized Ti₂C MXene as a High-Performance Adsorbent for Strontium Ions: A First-Principles Study

Radionuclide sequestration throughadsorption technology has attractedmuch attention due to its unique characteristics such as high removalefficiency, low cost, and ease of operation. In this work, the interactionmechanism of N-functionalized Ti2C MXene (Ti2CN2) as a potential adsorbent for the removal of strontiumions is investigated by using the first-principles method. Our resultsshow that surface N atoms are connected to Sr ions by a robust chemicalN-Sr bond, which provides a stronger interaction and greatercapacity (1.291g g(-1)) of Sr ion adsorption on Ti2CN2 than Ti2C with other surficial groupsO, F, and OH. Furthermore, the thermal stability of the adsorptionstructure of Sr on Ti2CN2 with full layer coverageat room temperature is verified by using ab initio molecular dynamicssimulations. Our results are expected to provide a new perspectivefor the design of MXene materials as an adsorbent for radionuclides.