ZnO nanorods/Ag nanoparticles heterostructures with tunable Ag contents: A facile solution-phase synthesis and applications in photocatalysis

Abstract

Needle-like ZnO nanorods (ZnO-NRs)/Ag nanoparticles (Ag-NPs) heterostructures with tunable silver contents have been successfully designed and constructed via a two-step hydrothermal approach on zinc foil. The as-fabricated heteroarchitectured composite was Ag-NPs with a size range about 30 to 50 nm in diameter assembled uniformly on the surface of needle-like ZnO-NRs, several micrometers long and about 480 nm wide near the half height of the nanorods. Through the variation of the reactant concentration such as silver nitrate, the silver content on the ZnO-NRs can be controllably tuned, which further greatly affected the photocatalytic performance of the decomposition of a representative dye pollutant of rhodamine B, and there is an optimum amount of secondary Ag-NPs. This facile method developed here also can be extended to construct other ZnO-based noble metal or semiconductor heterostructures on zinc substrates.

A general method to diverse silver/mesoporous–metal–oxide nanocomposites with plasmon-enhanced photocatalytic activity

“…7d shows the high resolution Ag 3d spectrum of the Ag nanoparticles in the Ag(5)/mesoporous-ZnO nanocomposite, presenting two individual peaks at 367.65 eV for Ag 3d 5/2 and at 373.62 eV for Ag 3d 3/2 , which confirms the formation of metallic Ag 0 by the photo-reduction of Ag + ions in aqueous solution [43]. The positions of Ag 3d peaks for the Ag/ZnO composite shift obviously to lower binding energies compared with those of the pure metallic Ag (Ag 3d 5/2 , 368.2 eV; Ag 3d 3/2 , 374.2 eV), which is similar to the results obtained from the Ag/ZnO heterostructures reported previously [44,45]. The binding energy shifts of Ag in the Ag/ZnO composite mainly arise from the electron transfer from Ag nanoparticles to the conduction band of ZnO at their interfaces, because the work function of metallic Ag (4.26 eV) is smaller than that of ZnO (5.3 eV) [46,47].…”

Ambient controlled synthesis of advanced core–shell plasmonic Ag@ZnO photocatalysts

“…3(B-D) ). 13,20,21 The binding energy of Ag 1+ is much lower than that of zero-valent Ag (Ag 0 ). Therefore, the shift of Ag 3d 5/2 and Ag 3d 3/2 to lower binding energies further verifies formation of the ZnO/Ag heterostructure.…”

“…3c Both the sensitizing property of the dye and the electron scavenging ability of silver together contribute to the interfacial charge transfer process to utilize the photoexcited electrons, as well as the VB holes, to form these active oxygen species. 21 In addition, the defects at the Ag@ZnO interface have also been demonstrated to suppress the charge recombination by transferring the photogenerated electrons to the dye in solution. 8 For the enhancement in the visible light region, the adsorbed RhB would also be photoactivated by the visible light, so that electrons can transfer from the singlet excited RhB (RhB*) to the conduction band (CB) of ZnO, Ag NWs/ NPs, and the shallow trap levels in the band gap of ZnO.…”

The enhancement of a self-powered UV photodetector based on vertically aligned Ag-modified ZnO nanowires

“…10,15 More recently, deriving from the benet of the localized surface plasmon resonance (LSPR), noble metals have drawn an intensive interest. 10,15 More recently, deriving from the benet of the localized surface plasmon resonance (LSPR), noble metals have drawn an intensive interest.…”