Boosted visible-light-driven degradation over stable ternary heterojunction as a plasmonic photocatalyst: Mechanism exploration, pathway and toxicity evaluation

The incorporation of plasmonic metals into semiconductors forming heterojunction photocatalysts is a promising route to enhance the photocatalytic performance in visible light. In this work, we reported the visible-light-driven one-dimensional (1D) nanostick silver/silver sulfide (Ag/Ag2S) photocatalyst combining with two-dimensional (2D) nanosheet reduced graphene oxide intersected by hollow struc-ture (h-RGO) was prepared via a feasible approach at room temperature. The density of Ag depositing on the surface of Ag2S was easily tuned by the concentration of sodium borohydride and the silicon diox-ide nanospheres were employed as templates in the preparation of h-RGO by the layer-by-layer (LBL) assembly. The ternary plasmonic Ag/Ag2S/h-RGO photocatalysts exhibited better photocatalytic perfor-mance for degradation of naphthalene (95.95%) and 1-naphthol (98.65%) under visible light than the pure Ag2S, composite Ag/Ag2S and composite Ag/Ag2S/RGO. Localized surface plasmon resonance of Ag, heterojunction formed between Ag/Ag2S and RGO and the unique characteristics of h-RGO, which included higher specific surface areas, more efficient reflections of light and more active sites than RGO for boosting separation efficiency of charge carriers, were all responsible for such enhancement. By combining the characterization results with various computations, the mechanism, potential degrada-tion pathways and the toxicity of the generated intermediates for photodegradation were examined. In addition to offering profound insight into the expansion of effective plasmonic photocatalysts with novel structures, the current study is beneficial to ease the environmental crisis to a certain extent. (c) 2023 Elsevier Inc. All rights reserved.

Automated summary

In this study, a visible-light-driven one-dimensional nanostick silver/silver sulfide (Ag/Ag2S) photocatalyst was prepared by combining it with a two-dimensional nanosheet reduced graphene oxide (RGO) intersected by hollow structure (h-RGO) at room temperature. The density of Ag on the surface of Ag2S was controlled by the concentration of sodium borohydride, and silicon dioxide nanospheres were used as templates in the preparation of h-RGO. The ternary plasmonic Ag/Ag2S/h-RGO photocatalysts showed superior photocatalytic performance for the degradation of naphthalene and 1-naphthol under visible light. The enhancement was attributed to the localized surface plasmon resonance of Ag, the heterojunction formed between Ag/Ag2S and RGO, and the unique characteristics of h-RGO. The study also examined the degradation mechanisms, potential pathways, and toxicity of the generated intermediates for photodegradation. In addition to expanding effective plasmonic photocatalysts with novel structures, this research is beneficial for alleviating environmental crises to a certain extent.