Using Al2O3 defect levels to enhance the photoelectrocatalytic activity of SnS2 nanosheets

Abstract Hexagonal SnS 2 nanosheets and Al 2 O 3 /SnS 2 composites were fabricated via a one-step hydrothermal synthesis method. The investigation indicates that hexagonal SnS 2 with diameters of 100–200 nm are well dispersed on the surface of Al 2 O 3 . The band gap of SnS 2 after coupling with 11 wt%-Al 2 O 3 is reduced by 0.042 eV compared with the pure SnS 2. The composite with 11 wt%-Al 2 O 3 shows the highest photocurrent density of 37 μA/cm 2 at 0.49 V ( vs . Ag/AgCl) under visible light (λ>420 nm), which is approximately 1.2 times that of the pure SnS 2 nanosheets. Photoelectrocatalytic measurements demonstrate that an appropriate amount of Al 2 O 3 can enhance the photoelectrocatalytic efficiency of SnS 2 . The 11 wt%-Al 2 O 3 /SnS 2 composite (AOSS-11) can degrade 85.9% MB after 3 h under visible light illumination at an applied potential of 0.49 V ( vs . Ag/AgCl). The highly effective photoelectrocatalytic activity of the Al 2 O 3 /SnS 2 composite is attributed to the efficient separation of photoinduced electron-hole pairs based on the defect levels. This work may provide a new design idea for constructing the effective SnS 2 -based photocatalysts with other defective semiconductors.