![]() However, size, shape, inter-particle coupling and the surrounding medium of the plasmonic nanostructure affect the solar absorption and overall photocatalytic efficiency of the hybrid hetero-structures. In this regard, decoration of TiO 2/ZnO with noble metal nanoparticles is a promising method to reduce the recombination of the photogenerated electrons and enhance the photo-degradation activity 6, 7, 8, 9, 10. The formation of this metal-semiconductor hetero-junction is an effective way to enhance charge carrier separation and improve the photocatalytic efficiency 3, 4, 5. When these plasmonic nanoparticles attach to semiconductors, a Schottky barrier will form at the interface between the metal and the semiconductor. These nanoparticles are able to strongly concentrate the incident light on the surface and enhance photochemical reactions. Plasmonic nanoparticles have a strong absorption in the visible region of the spectrum due to localized surface plasmon resonances (LSPR). Coupling with noble metals is an effective approach to enhance the visible light absorption and photocatalytic activity of ZnO. Therefore, different modifications such as metal and non-metal doping, dye sensitization, and coupling with other semiconductors have been attempted to enhance the visible light absorption of ZnO. ![]() This large band gap suppresses the solar driven photocatalysis reactions. ![]() However, the main drawback of ZnO in photocatalytic applications is the wide band gap value of 3.3 eV, which requires UV illumination. ZnO can completely remove and degrade organic dyes such as methylene blue (MB) to CO 2 and H 2O under UV irradiation. In particular, ZnO has been extensively used due to its non-toxicity, low cost and high stability against photo-corrosion in photo degradation studies 1, 2. In comparison to conventional wastewater treatment methods, applying nanostructured semiconductors is an efficient and economically favorable technique. In this regard, semiconductor photocatalysts have attracted the attention for water treatment and environmental remediation applications. Photocatalysis is a promising route to remove toxic dyes from waste water. Organic dyes from industries such as textiles, paper, leather, printing inks and cosmetics release non bio-degradable contaminants into water. This work provides insight into the design of a new and durable plasmonic-metal oxide nanocomposite with efficient dye degradation even without light illumination. Nevertheless, the synthesized Ag/ZnO decomposed methylene blue in visible light, and the silver oxidation only affected the catalytic activity in the dark. Silver oxidation in the hetero-structure changed the metal-semiconductor interface and suppressed the plasmonic enhancement. Band-edge tuning causes effective visible light absorption and enhances the dye degradation efficiency of Ag/ZnO nanostructures. The absorption edge of the hybrid nanostructure shifts toward the visible region of the spectrum due to a combination of the Ag plasmonic effect and the defects in ZnO. X-ray photoelectron spectroscopy (XPS) and photoluminescence spectroscopy results confirmed the existence of defects in ZnO in the hybrid nanostructures these defects act as electron traps and inhibit the recombination of electron-hole pairs. In this nanostructure, ZnO was synthesized using the arc discharge method in water and was coupled with Ag via a chemical reduction method. This study not only endeavors to clarify the charge-transfer interactions of TCNQ with silver, but also presents a finding of enhanced charge transfer between Ag 13 and TCNQ indicating potential for candidate building blocks of granular materials.A new synergetic hybrid Ag/ZnO nanostructure was fabricated which is able to cause photocatalytic degradation (in high yields) of methylene blue under visible light as well as in the dark. ![]() The behavior of TCNQ adsorbed on the tetrahedral Ag 20 cluster was even found in good agreement with the experimental measurement of TCNQ molecules on a single-crystal Ag(111) surface. Furthermore, frontier molecular orbital (FMO) and natural bond orbital (NBO) analysis of the complexes provides a vivid illustration of electron cloud overlap and interactions. We show here a comprehensive spectroscopic analysis for the two CT complexes on the basis of Raman and infrared activities. Charge transfer (CT) from silver clusters to TCNQ molecules initiates the Ag–N bond formation at selective sites resulting in the formation of different isomers of Ag 13–TCNQ and Ag 20–TCNQ complexes. Interactions between tetracyanoquinodimethane (TCNQ) and two typical silver clusters Ag 13 and Ag 20 are studied by first-principles DFT calculations.
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