Three-dimensional covalent nanochannels in TiO2@Ti-MOF/MXene heteroarchitectures enable selective 4-aminophenol detection in complex aqueous systems

Abstract

4-Aminophenol (4-AP), a crucial organic intermediate in the synthesis of acetaminophen, poses significant toxicity and potential environmental and health risks. Titanium dioxide@ titanium-based metal–organic frameworks (TiO₂@Ti-MOFs) form a three-dimensional heterogeneous composite structure by covalently binding to the surface of 2D transition metal carbides and nitrides (MXenes). The synergistic effect between the porosity of titanium-based metal–organic frameworks (Ti-MOFs) and the layered structure of MXenes provides abundant adsorption sites, effectively enriching the target molecule 4-AP and enhancing the sensor's selectivity. The high conductivity of MXenes, combined with the semiconductor properties of TiO₂@Ti-MOFs, accelerates electron transfer on the electrode surface, resulting in an increased response current and improved sensitivity and detection range. The detection range of the TiO₂@Ti-MOF/MXene electrochemical sensor spans from 0.5 to 50 μM, with a detection limit of 0.16 μM. This sensor is effectively applicable for detecting 4-AP in real water samples, such as tap water and Qingshan Lake water, demonstrating satisfactory recovery.