TiO₂-MXene/PEDOT:PSS Composite as a Novel Electrochemical Sensing Platform for Sensitive Detection of Baicalein

In this work, TiO₂-MXene/poly (3,4-ethylenedioxythiophene): poly(styrenesulfonate) (PEDOT:PSS) composite was utilized as an electrode material for the sensitive electrochemical detection of baicalein. The in-situ growth of TiO₂ nanoparticles on the surface of MXene nanosheets can effectively prevent their aggregation, thus presenting a significantly large specific surface area and abundant active sites. However, the partial oxidation of MXene after calcination could reduce its conductivity. To address this issue, herein, PEDOT:PSS films were introduced to disperse the TiO₂-MXene materials. The uniform and dense films of PEDOT:PSS not only improved the conductivity and dispersion of TiO₂-MXene but also enhanced its stability and electrocatalytic activity. With the advantages of a composite material, TiO₂-MXene/PEDOT:PSS as an electrode material demonstrated excellent electrochemical sensing ability for baicalein determination, with a wide linear response ranging from 0.007 to 10.0 μM and a lower limit of detection of 2.33 nM. Furthermore, the prepared sensor displayed good repeatability, reproducibility, stability and selectivity, and presented satisfactory results for the determination of baicalein in human urine sample analysis.