Platinum quantum dots-multiwalled carbon nanotubes/nickel foam composite cathode with efficient electron transport channels: Low-energy consumption degradation of tigecycline based on the SMSI effect

To address the water pollution issue caused by high-generation tetracycline antibiotics (HGTs), this study constructed a multi-level platinum quantum dot-multi-walled carbon nanotube/nickel foam composite electrode (PMN), achieving efficient electrocatalytic degradation of HGTs. Through the multi-scale hierarchical structural design consisting of a nickel foam (NF) macroscale layer, a multi-walled carbon nanotube (MWCNTs) mesoscale layer, and a platinum quantum dot (Pt-QDs) microscale layer, the electrode effectively inhibits the agglomeration of Pt-QDs and promotes mass transfer. The strong metal-support interaction (SMSI) accelerates electron transfer, and calculations of differential charge density and projected density of states (PDOS) confirm that MWCNTs transfer electrons to Pt-QDs, enhancing the adsorption and activation of tigecycline (TGC) by active sites. Under optimal conditions, the TGC removal efficiency reaches 92.39% within 30 min, with an energy consumption of only 0.166 kWh/m 3 . Via active species analysis, density functional theory (DFT) calculations, and liquid chromatography-mass spectrometry (LC-MS) technology, it is revealed that the degradation process is synergistically driven by cathode-generated H*/H 2 O 2 and anode-generated ·OH/reactive chlorine species (RCS), and the degradation pathways of TGC are clarified. Cyclic experiments and biotoxicity assessments confirm that the PMN electrode exhibits excellent stability, and the toxicity of intermediates is significantly reduced. The electrode also performs stably and efficiently in a continuous-flow reactor, providing a feasible solution for the removal of HGTs in actual water bodies.