In situ construction of MXene@UiO-66-NH2 composite membranes with optimized catalytic sites for enhanced phenol electrocatalytic degradation

To tackle the critical challenge of efficient treatment for phenolic industrial wastewater, MXene@UiO-66-NH 2 composite powder was synthesized via a self-assembly approach. The powder was then immobilized on the surface of a PEI-modified PES substrate through vacuum filtration, thus successfully fabricating MXene@UiO-66-NH 2 /PES composite membranes. Characterizations including SEM, XRD and XPS confirmed that hydrogen bonds and weak coordination bonds formed between MXene and UiO-66-NH 2 . These interactions effectively suppressed the stacking of MXene and agglomeration of UiO-66-NH 2 , and constructed continuous electron transport pathways and ordered porous diffusion channels. The optimal performance was achieved when the UiO-66-NH 2 loading of 75 mg: cyclic voltammetry tests revealed high current density and favorable reversible redox behavior, and electrochemical impedance spectroscopy results indicated minimal charge transfer and diffusion resistance. In phenol degradation experiments, the degradation efficiency remained consistently above 90% within 5 h, and the composite membrane maintained excellent stability even after 72 h of cyclic operation. Active species quenching experiments verified that the core degradation mechanism of the composite membrane relies on the synergistic effect of superoxide radicals (·O 2 − ) and hydroxyl radicals (·OH): ·O 2 − initiated the initial activation of the benzene ring, while ·OH drove the subsequent deep oxidation and mineralization processes. This work realizes the integration of membrane separation and electrocatalytic degradation functions, breaks through the performance trade-off bottleneck of MXene-MOF composite membranes, and provides a novel and scalable preparation strategy for high-performance catalytic membranes, as well as technical support and a theoretical paradigm for the advanced treatment of phenolic industrial wastewater.