Construction of a Novel S-Scheme Heterojunction Piezoelectric Photocatalyst Cu 2 O/Zno Nanoarrays For Boosting Photocatalytic Performance

Abstract

The combination of light and mechanical energy constitutes an effective way to reduce photogenerated electron–hole recombination in catalytic reactions. Herein, nanorod arrays composed of light-sensitive Cu2O and piezoelectric ZnO were fabricated using a facile solution method and an ionic-layer adsorption approach. The experimental results show that the growth of Cu2O nanoparticles on the surface of ZnO nanoarrays enhances considerably the absorption of the resulting photocatalysts. Photoelectric chemistry and photoluminescence analyses reveal that the Cu2O/ZnO nanoarrays exhibit high electron–hole separation efficiency. Under light irradiation and ultrasonic vibration, Cu2O/ZnO nanoarrays synthesised on a stainless steel mesh (4.0 × 3.0 cm, ~40 mg) show excellent pollutant degradation performance with a degradation efficiency of 99.08% for a 5 mg/L methylene blue solution within 30 min and good degradation efficiency for quinolone antibiotics under the same conditions. The enhanced degradation performance can be attributed to the S-scheme heterostructure of the Cu2O/ZnO nanoarrays and the bending structure of the ZnO nanoarrays induced by piezoelectric polarisation during the degradation process. This study provides a theoretical basis for the investigation of the synergistic effect of solar energy and mechanical energy on piezo-photocatalysts and a new idea for the high-efficient degradation of organic pollutants.

Keywords: Photodegradation, Piezoelectric effect, Cu2O/ZnO nanoarrays, S-scheme heterostructure