High Performance Generation of H 2 O 2 under Piezophototronic Effect with Multi-Layer In 2 S 3 Nanosheets Modified by Spherical ZnS and BaTiO 3 Nanopiezoelectrics.

Manipulating the separation and transportation of photoexcited charge carriers in photoresponsive semiconductors via the piezoelectric polarization effect is an emerging strategy in the field of artificial photosynthesis. However, existing semiconductor photocatalysts, both with a wide range absorption for visible light and superior piezoelectricity are very scarce, leading to a low reactivity of photocatalysis. Here, a multi-layer In 2 S 3 nanosheet modified with spherical ZnS and BaTiO 3 nanopiezoelectrics (ZnS/In 2 S 3 /BTO) is reported, generating approximately 378 µm of H 2 O 2 in 100 min (and the concentration is still increasing) under co-irradiation of visible light and ultrasound (piezophotocatalysis) in ethanol-water solution; this concentration is higher compared with two phases piezoelectric heterostructures (i.e., ZnS/BTO, In 2 S 3 /BTO, and ZnS/In 2 S 3 ) and pure compounds (i.e., ZnS, In 2 S 3 , and BTO), and also higher than that of independent piezo- (≈254 µm) and photocatalysis (≈120 µm). Moreover, the concentration of H 2 O 2 generated on ZnS/In 2 S 3 /BTO can be as high as approximately 1160 µm in 5 h of piezophotoreaction after experiencing six cycles of visible light concurrent with ultrasound irradiation. The enhancement of H 2 O 2 yield on ZnS/In 2 S 3 /BTO in piezophotocatalysis can be attributed to the piezopotential-induced internal electric polarization field promoting the separation of photoexcited charge carriers, thus boosting the rate of surface photoreaction.