Double transition metal carbide Mo2TiC2Tx MXene architectured with in-situ synthesized gold nanoparticles for SERS enhancement

Two-dimensional (2D) double transition metal (DTM) MXenes have yet to be fully explored for surface-enhanced Raman scattering (SERS), despite their unique properties. In this study, we present a novel Mo2TiC2Tx/Au hybrid synthesized through the in-situ reduction of chloroauric acid on Mo2TiC2Tx MXene sheets, where functional groups act as reducing agents. This method produces a highly sensitive, stable, and robust SERS substrate, with varying gold nanoparticle loadings based on precursor volume. The substrate synthesized with 20 mu L precursor volume shows an enhancement factor (EF) of 109 and a remarkable detection limit of 10_ 10 M for methylene blue (MB), a resonant organic dye. It also demonstrates a detection limit of 10_ 7 M for non-resonant dyes like Rhodamine 6G (R6G). The enhanced SERS performance is attributed to the synergistic chemical enhancement (CE) from Mo2TiC2Tx and electromagnetic enhancement (EE) from the gold nanoparticles. Furthermore, the Mo2TiC2Tx/Au hybrid exhibits excellent signal stability (85 % of the initial signal) and good reproducibility (relative standard deviation of 17.4 %). These results highlight the promising potential of 2D DTM MXene-Au hybrids as SERS substrates and open new avenues for further exploration in advanced sensing applications.