Enhanced piezoelectric photocatalytic activity of MXene/ZnS/FeO via Three-in-One strategy based on dual Schottky heterojunction, interface electric field, and oxygen vacancy for pollutant degradation and removal.

Synergism of piezoelectricity and photocatalysis is an effective approach for pollutant degradation and removal, and has garnered considerable attention. Nonetheless, great challenges still remain in recombination and slow migration rate of charge carriers. For response, a novel Three-in-One strategy based on MXene/ZnS/FeO (MZF) was developed to enhance the piezoelectric photocatalytic activity via achieving a triple effect: Dual Schottky heterojunction, Interface electric field, and Oxygen vacancy. The integration of triple effect enabled MZF to achieve remarkable piezo-photocatalytic performance, greatly improving the separation efficiency and migration rate of charge carriers, which increased the pollutant removal rate by 2.6 times through the synergistic effect. MZF achieved a higher degradation rate constant of 0.10, surpassing MXene (0.022), ZnS (0.029), FeO (0.010), MXene/ZnS (0.071), MXene/FeO (0.030), and ZnS/FeO (0.024), overall leading to a 100 % elimination of typical pollutants such as fluoroquinolones (FQs). Additionally, it demonstrated a superior removal capability compared to unitary and binary materials. The degradation products of FQ were identified by UPLC-MS, and degradation pathways were articulated as cleavage of the quinolone ring, cleavage of the piperazine ring, and defluorination. H NMR analysis confirmed that MZF completely degraded FQ into inorganic small molecule compounds. Toxicity analyses of the degradation products, conducted using toxicity estimation software and bacterial tests, indicated low and even non-toxic levels. This study outlines an innovative collaborative strategy to advance piezoelectric photocatalysis for efficient pollutant treatment.