Ag2S Quantum Dots Based on Flower-like SnS2 as Matrix and Enhanced Photocatalytic Degradation

Ag2S quantum dots were dispersed on the surface of SnS2 nanoflowers forming a heterojunction via in-situ ion exchange to improve photocatalytic degradation of RhB. All samples exhibit the hexagonal wurtzite structure. The size of Ag2S@SnS2 composites are 1.5 m flower-like with good crystallinity. Meanwhile, the E-g of 3% Ag2S@SnS2 is close to that of pure SnS2. Consequently, the 3% Ag2S@SnS2 composite displays the excellent photocatalytic performance under simulated sunlight irradiation with good cycling stability, compared to the pure SnS2 and other composites. Due to the blue and yellow luminescence quenching, the photogenerated electrons and holes is effectively separated in the 3% Ag2S@SnS2 sample. Especially, the hydroxyl radicals and photogenerated holes are main active species.