Construction of Ultrafine Ag 2 S NPs Anchored onto 3D Network Rodlike Bi 2 SiO 5 and Insight into the Photocatalytic Mechanism.

A novel three-dimensional (3D) network rodlike Ag ₂ S/Bi ₂ SiO ₅ photocatalyst with a p-n heterostructure composed of ultrafine Ag ₂ S nanoparticles (NPs) and Bi ₂ SiO ₅ nanosheets was prepared using an anionic self-regulation strategy by a two-step hydrothermal process. The architecture facilitated the efficient transfer and separation of photogenerated electron-hole pairs. The optimal Ag ₂ S/Bi ₂ SiO ₅ composite (ABSO _0.10 ) exhibited an excellent reduction activity (93.5% Cr(VI) removal in wastewater containing 50 mg·L ^-1 Cr(VI) within 90 min under visible light), which was about 11.2 and 25.6 times higher than that of the pristine Ag ₂ S and virgin Bi ₂ SiO ₅ , respectively. Assisted by experiments and density functional theory (DFT) calculations, a possible photocatalytic mechanism for Cr(VI) reduction over the Ag ₂ S/Bi ₂ SiO ₅ composite under visible-light irradiation was proposed.