In Situ Growth Facilitating the Piezo-Photocatalytic Effect of Zn 1- x Cd x S/ZnO Nanorods for Highly Efficient H 2 Production.

Photocatalytic H 2 production holds promise for alleviating energy and environmental issues. The separation of photoinduced charge carriers plays vital roles in enhancing the activity of photocatalytic H 2 production. The piezoelectric effect has been proposed to be effective in facilitating the separation of charge carriers. However, the piezoelectric effect is usually restricted by the noncompact contact between the polarized materials and semiconductors. In this study, Zn 1- x Cd x S/ZnO nanorod arrays on stainless steel for piezo-photocatalytic H 2 production are fabricated by an in situ growth method, achieving an electronic-level contact between Zn 1- x Cd x S and ZnO. The separation and migration of photogenerated charge carriers in Zn 1- x Cd x S are significantly improved by the piezoelectric effect induced by ZnO under mechanical vibration. Consequently, under solar and ultrasonic irradiation, the H 2 production rate of Zn 1- x Cd x S/ZnO nanorod arrays achieves 20.96 μmol h -1 cm -2 , which is 4 times higher than that under solar irradiation. Such a performance can be attributed to the synergies of the piezoelectric field of bent ZnO nanorods and the built-in electric field of the Zn 1- x Cd x S/ZnO heterostructure, which efficiently separate the photoinduced charge carriers. This study provides a new strategy to couple polarized materials and semiconductors for highly efficient piezo-photocatalytic H 2 production.