Expanded interlayer spacing of SnO2 QDs-Decorated MXene for highly selective luteolin detection with Ultra-Low limit of detection

Although there have been advancements in electrochemical catalysts for luteolin detection, their practical use is constrained by low sensitivity, inadequate selectivity, and unsatisfactory limit of detection. MXene, a class of 2D materials, possesses exceptional physical–chemical properties that make it highly suitable for electrochemical detection. Nevertheless, the self-stacking and limited interlayer spacing of MXene impede its extensive application in electrochemical detection. Herein, a SnO2 QDs-MXene composite is synthesized for selective electrochemical detection of luteolin. Inserting SnO2 QDs between tightly stacked MXene layers expands the d-spacing of MXene, enhancing the specific surface area and enabling abundant active sites for redox reactions. The inclusion of MXene in the modified SnO2 QDs-MXene/GCE electrode significantly enhances electron transfer. As a result, the electrode demonstrates exceptional luteolin detection capabilities, including a wide linear range (0.1–1200 nM), high sensitivity (12.4 μA μM−1), and an ultra-low limit of detection (0.14 nM). Additionally, the SnO2 QDs-MXene/GCE electrode exhibits good repeatability, excellent reproducibility, remarkable stability, and high selectivity, making it suitable for practical sample analysis. This research contributes to advancing ultra-low limit of detection sensors for accurate luteolin detection.