Surface-Enhanced Raman Scattering of the Double Transition Metal Mo2TiC2–Ox MXene-Based Structures

Surface-enhanced Raman scattering (SERS) sensors based on a commercial three-component double transition metal Mo2TiC2–Ox MXene are presented. It is shown that the threshold of detection of rhodamine 6G with the SERS sensors is 10–8 M, which by an order of magnitude exceeds the results obtained previously on the Mo2TiC2–Ox-based SERS sensors. The Mo2TiC2–Ox structure has been analyzed by scanning and transmission electron microscopy, energy-dispersive spectroscopy, and Raman spectroscopy. The dynamics of the rhodamine 6G detection threshold change has been studied using the Mo2TiC2–Ox-based SERS sensors. The data obtained have allowed the estimation of the contribution of metal components of the residual precursor to the Mo2TiC2–Ox SERS activity and the identification of mechanisms of degradation of the SERS properties of the investigated compound. The reported results are of great importance for understanding the relationship between the SERS activity and structural properties of MXenes and for evaluating their application potential in the field of SERS sensing.