Synergistic Plasmonic and Schottky Effects in Ag Nanoparticle-Decorated 4,5-Dibromofluorescein Nanosheets for Photocatalytic Hydrogen Evolution

Abstract

Using plasmonic metal nanoparticles (NPs) represents an effective strategy to overcome insufficient visible-light absorption and severe photogenerated charge recombination in organic photocatalysts via local surface plasmon resonance (LSPR)-triggered hot-carrier injection and regulated interfacial charge transport. Herein, plasmonic Ag nanoparticles (Ag NPs)-decorated 4,5-dibromofluorescein (DBF) nanosheets were readily prepared through a convenient in situ photodeposition strategy to construct Ag/DBF nanosheets for photoinduced hydrogen generation under visible-light. Benefiting from the intrinsic light-harvesting capability of DBF, together with the combined effects of plasmonic Ag NPs and interfacial Schottky junction formation, the Ag/DBF nanosheets exhibit significantly enhanced charge separation and interfacial electron-transfer efficiency. Under visible-light irradiation, plasmon-induced hot electrons produced by Ag NPs migrate into the conduction band of DBF, while the Ag NPs simultaneously function as electron sinks to inhibit charge carrier recombination and accelerate surface proton reduction. The optimized 6.0 wt % Ag/DBF nanosheets exhibit a hydrogen evolution rate of 1265.2 μmol g–1 h–1, 111-fold higher than that of pristine DBF. It retains robust structural and photocatalytic stability in multiple cycling runs. This work reveals the synergistic coupling mechanism between plasmonic hot-electron transfer and organic semiconductor photocatalysis, offering an effective strategy to construct high-performance plasmonic organic photoactive materials for solar-to-hydrogen conversion.