Fibrous MoS2/Bi2S3/BiFeO3 ternary heterojunction boosts piezoelectric photocatalytic performance

Photocatalytic removal of antibiotic such as ciprofloxacin from polluted water is of great value for ecoenvironment protection. To further enhance the piezoelectric effect in photocatalysis, we designed and synthesized a ternary heterojunction piezoelectric photocatalyst through uniformly loading MoS2 nanosheets onto BiFeO3 (BFO) nanofibers, namely MoS2/Bi2S3/BFO. Piezoresponse force microscopy and Kelvin probe force microscopy demonstrated its enhanced piezoelectric properties, showing a maximum amplitude displacement of 395.51 pm under a voltage of 9.91 V and a surface potential difference of 66.50 mV. Finite element simulations indicated that the ternary heterojunction could achieve a larger piezoelectric potential. Piezoelectric photocatalytic degradation experiments revealed that MoS2/Bi2S3/BFO achieved a ciprofloxacin degradation efficiency of 96.6 % within 75 min, significantly higher than that of pure piezoelectric catalysis (25.5 %) and photocatalysis (60.5 %). Analysis of intermediate products and detection of active species (center dot OH and center dot O2-) during degradation suggested an S-Scheme migration pathway of photogenerated charge carriers, enhancing the piezoelectric photocatalytic performance of the material. This study provides an efficient ternary heterojunction composite piezoelectric photocatalyst for the antibiotic degradation and energy conversion, thus offers a new approach for developing novel BFO-based composite piezoelectric photocatalysts.