Synthesis of ternary ZnO/ZnS/MoS2 piezoelectric nanoarrays for enhanced photocatalytic performance by conversion of dual heterojunctions

Highlights: • Ternary piezoelectric nanoarrays were firstly synthesized for piezo-photocatalysis. • The nanocomposites consist of ZnO nanorods, ZnS nanoparticles and MoS₂ nanoflakes. • The photocatalytic property is significantly enhanced by stir induced piezoelectricity. • The enhancement can be owing to dual heterojunctions modulated piezo-photocatalysis. • The mechanism is diagrammed by energy band method and proofed by ESR technique. The recombination of photogenerated charge carriers hinder the application of photocatalyst. In this study, ternary piezoelectric photocatalyst consisting of ZnO, ZnS and MoS₂ nanostructures has been synthesized by a two-step hydrothermal method, which exhibits excellent piezo-photocatalytic efficiency while degrading methylene blue (MB). The piezo-photocatalytic degradation efficiency of MB is ~2.5 times of that without piezoelectricity. Moreover, the ZnO/ZnS/MoS₂ nanocomposites exhibit good piezo-photocatalytic stability; after 5 cycles, the efficiency remains at ~80% of the initial value. This mechanism can be attributed to the coupling effect of piezoelectricity, photocatalysis and dual heterojunctions, as verified by ESR and diagrammed by band energy structure.