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 μm 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.