Temperature-mediated modulation of S vacancies in ultrathin ZnIn2S4 nanosheets inducing charge separation for enhanced photocatalytic degradation

The flower-like ZnIn2S4 with S vacancies have been prepared via heat treatment method. • S vacancies induce defect states acting as electron traps. • These traps effectively capture electrons and separate photogenerated carriers. • ZnIn2S4 with S vacancies exhibits outstanding degradation performance for RhB and MBT. Photocatalytic degradation is an effective wastewater treatment, but the separation of photogenerated carriers limits the efficiency. Herein, flower-like ZnIn 2 S 4 (ZIS) samples composed of ultrathin nanosheets with different numbers of S-vacancies are synthesized. S vacancies as electron traps promote the separation of photogenerated charges and also serve as active centers to promote the adsorption of O 2 to produce more ·O 2 − and 1 O 2 . The experimental results confirm that the photocatalytic efficiency is related to the number of S vacancies. ZIS-100, which possesses the appropriate number of S vacancies, delivers the best photocatalytic degradation activity. After light irradiation for 30 and 180 min, ZIS-100 degrades 97.8% of RhB and 94.9% of the MBT. The photocatalytic degradation pathway is analyzed, and a mechanism is proposed for defective ZnIn 2 S 4 . This work offers valuable insights into the role and mechanism of defects to enable the design of more efficient defective photocatalytic materials. Download: Download high-res image (87KB) Download: Download full-size image