Dual‐Functional MXene/SrTa 2 O 6 Nanohybrids for Ultrafast Dye Removal and Highly Sensitive Biosensing

Abstract In this study, a dual‐functional nanohybrid composed of Ta 2 O 5 ‐initiated SrTa 2 O 6 and Ti 3 C 2 T x MXene (MTS) is developed for ultrafast dye adsorption and highly selective electrochemical dopamine sensing. Structural analysis confirmed the formation of strong interfacial Ta─O and Sr─O bonds between Ti 3 C 2 T x and SrTa 2 O 6 , and both surface roughness and pore volume of MTS increased by more than twice as compared to pristine MXene. The MTS exhibited extremely fast and selective adsorption of methylene blue (MB), where the adsorption rate constant reached 0.812 min −1 . The electrochemical measurements on MTS showed significantly enhanced charge transfer and surface activity, leading to a very low detection limit (LOD) of 1.52 µ m for dopamine. Density functional theory (DFT) calculations revealed favorable binding energies, charge redistribution, and orbital hybridization between the MXene and the SrTa 2 O 6 cluster, validating the experimental results. Furthermore, charge density difference (CDD) and electron localization function (ELF) investigations suggested chemisorption as a potential mechanism. Conclusively, the MTS demonstrated superior dual‐functionality in both fields of dye adsorption and biosensing, making it a promising candidate for applications in wastewater treatment and biomedical diagnostics.