Engineered ZnO/Ti3C2Tx MXene heterostructures with optimized composition for dual-function photocatalytic degradation and pathogenic inactivation

In this study, we report the synthesis of Ti₃C₂T_x MXene/ZnO heterojunction derived from Ti₃AlC₂ MAX phase precursor. High-resolution transmission electron microscopy (HRTEM) and selected area electron diffraction (SAED) reveal attachment of ZnO nanoparticles onto the MXene basal plane, characterized by distinct interfacial lattice aberrations and the retention of the hexagonal Ti-C framework along the [0001] zone axis. X-ray photoelectron spectroscopy (XPS) confirms the formation of covalent Ti-O-Zn bridging bonds, which act as a chemical “glue” to facilitate electronic communication. Electrochemical impedance spectroscopy (EIS) demonstrates a dramatic reduction in charge-transfer resistance (from 131 MΩ to 5 kΩ) and a fast relaxation time of about 7 µs. The ZM5 composite exhibits superior multi-functional performance, achieving a 58.7% degradation efficiency of formic acid and potent antibacterial activity with inhibition zones up to 16 mm against S. Enteritidis. These results pave the way for the design of chemically anchored 2D heterojunctions optimized for advanced environmental remediation and antimicrobial technologies.