Visible-light Plasmonic Photocatalyst Research Articles

A g-C3N4@Au@SrAl2O4:Eu2+,Dy3+composite as an efficient plasmonic photocatalyst for round-the-clock environmental purification and hydrogen evolution

Here, we demonstrate a g-C3N4@Au@SrAl2O4:Eu2+,Dy3+composite as a novel efficient self-luminous visible-light plasmonic photocatalyst for photocatalytic degradation of organic pollutants and hydrogen evolution from water around the clock.

Dendritic hierarchical AgCl prepared in the interface of gas–solid as the precursors of the visible-light plasmonic photocatalysts of Ag–AgCl

A new photocatalyst structure, dendritic hierarchical AgCl assembled by numerous nanoscaled particles, was obtained via simple and effective one-step gas–solid interfacial method for the first time. The macromorphology of the prepared AgCl also displays a dendritic shape as the microperspective. The Ag–AgCl made from the dendritic hierarchical AgCl exhibits a stable photocatalytic performance.

Synthesis and photocatalytic performance of Ag/AgCl/ZnO tetrapod composites

Ag/AgCl is a visible-light plasmonic photocatalyst that has attracted considerable attention because of its high visible-light absorption and activity owing to the surface plasmon resonance of noble-metal nanoparticles. In this study, Ag/AgCl/ZnO tetrapod composite was prepared by introducing ZnO tetrapods into Ag/AgCl prepared by a polydopamine reduction route. Ag/AgCl was densely deposited on the three-dimensional support framework provided by the ZnO tetrapods. The framework possessed a certain degree of porosity, thereby improving the specific surface area of the Ag/AgCl/ZnO composite. The interaction of ZnO with Ag/AgCl further increased the separation and transfer of electron–hole pairs. The Ag/AgCl/ZnO composite showed excellent photocatalytic activity and good stability. Under xenon lamp irradiation for 20 min, degradation of rhodamine B reached 90%. After four recycling tests, degradation remained stable without any sign of reduction. Ag/AgCl/ZnO tetrapod composite is shown to be a kind of green photocatalyst offering high activity, good stability, and recyclability.

Magnetically separable Ag/AgBr/NiFe2O4 composite as a highly efficient visible light plasmonic photocatalyst

A magnetic Ag/AgBr/NiFe2O4 plasmonic photocatalyst was firstly prepared by coupling a hydrothermal route with a solvothermal method. The as-synthesized Ag/AgBr/NiFe2O4 was characterized by XRD, XPS, FE-SEM, UV–vis DRS, PL and BET surface area. Under visible light irradiation, the resulting Ag/AgBr/NiFe2O4 exhibited a higher photocatalytic activity for rhodamine B (RhB) degradation compared with Ag/AgBr, which was ascribed to the heterostructured Ag/AgBr/NiFe2O4 and the surface plasmon resonance (SPR) effect of Ag nanoparticles. Moreover, the Ag/AgBr/NiFe2O4 plasmonic photocatalyst can be recovered and recycled by a magnetic field along with good stability. A plausible mechanism is also proposed via active species trapping experiments, which indicating that the superoxide radicals (O2−•) are the main reactive oxygen species for RhB degradation in Ag/AgBr/NiFe2O4 suspension under visible light.

Ternary Ag/AgCl-(BiO)2CO3 composites as high-performance visible-light plasmonic photocatalysts

A ternary plasmonic Ag/AgCl-(BiO)2CO3 photocatalyst was successfully synthesized via a facile method. The as-prepared samples were characterized by X-ray diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, UV–vis diffuse reflection spectra, N2 adsorption-desorption isotherms, photoluminescence spectra, photocurrent generation measurement, time-resolved fluorescence and in situ FT-IR spectra. The Ag/AgCl-(BiO)2CO3 composites exhibited outstanding visible-light photocatalytic performance for removal of NO in air, which can be ascribed to the cooperation of surface plasmon resonance effect (SPR effect), surface scattering and reflecting effect (SSR effect) and efficient separation of electron-hole pairs. Moreover, the in situ DRIFTS were applied to elucidate the photocatalytic oxidation process for NO removal and also can further explain the enhanced photocatalytic activity of ternary Ag/AgCl-(BiO)2CO3 composites. And a conceivable visible-light photocatalysis mechanism was proposed in detail. The present work could provide a new perspective for the fabrication and understanding of plasmon-enhanced visible-light photocatalysts.

Synthesis and Properties of Nano Gold-Zinc Titanate Composite as a Novel Visible-light Plasmonic Photocatalysts for Solar Hydrogen Evolution

Synthesis and Properties of Nano Gold-Zinc Titanate Composite as a Novel Visible-light Plasmonic Photocatalysts for Solar Hydrogen Evolution

Mechanistic understanding of ternary Ag/AgCl@La(OH)3 nanorods as novel visible light plasmonic photocatalysts

A new visible light mechanism was revealed for ternary Ag/AgCl@La(OH)3 nanorods with highly enhanced activity toward NO removal.

A facile synthesis of Ag/AgCl hybrid nanostructures with tunable morphologies and compositions as advanced visible light plasmonic photocatalysts.

This paper describes a simple and fast aqueous-phase route to the synthesis of Ag/AgCl hybrid nanostructures. These hybrid nanostructures were synthesized by reduction of AgCl nanoparticles with controlled shapes prepared by reacting Ag(+) with Cl(-) in the presence of polyethyleneimine (PEI) in an aqueous-phase. We could easily control the morphology and composition of the nanostructures by varying the experimental conditions, including the reaction temperature and the amount of the reducing agent. The as-synthesized Ag/AgCl hybrid nanostructures exhibited enhanced photocatalytic activity and stability during the degradation of methyl orange under visible light irradiation because of their strong surface plasmon resonance (SPR) effect.

Synthesis and characterization of Ag/TiO2 plasmonic photocatalyst supported on stainless steel webnet

Plasmonic nanostructures present substantial function in the advancement of modern materials science and technology. Plasmon-enhanced solar light is harvested to enhance the solar-to-fuel energy conversion efficiency. Both organic and inorganic semiconductor materials often serve as photocatalysts for the direct conversion of solar energy into fuels, owing to their superior stability, environmental compatibility and photocatalytic activity. However, semiconductor efficiency can be hindered by their inability to absorb visible light due to the vast band gap. More recently, a number of research has been performed to enhance photocatalyst and photovoltaic device efficiency by integrating plasmonic nanoparticles (NPs) with semiconductor materials. The presence of plasmonic NPs causes greater semiconductor absorption cross sections due to robust field enhancement, light absorption at longer wavelengths and enhanced electron–hole charge separation in semiconductor media, thus maximizing the efficiency of photocatalytic devices. In this study, we have prepared a new visible-light-driven Ag/TiO2 nanoparticles plasmonic photocatalyst coated on webnet stainless steel by the dip-coating method to enhance the visible light plasmonic photocatalyst. FESEM, EDX and UV–vis spectra analyses were carried-out to characterize the prepared catalysts. According to these tests, the Ag/TiO2 coated on the stainless steel webnet functioned quite well. In addition, the maximum conversion of carbon dioxide was achieved at about 20%. This study may provide new insight into the design and preparation of advanced visible-light photocatalytic materials.

Interfacial properties of the enhanced visible-light plasmonic Ag/Bi2WO6 (0 0 1) nanocomposite

First principle calculations are performed to study the interfacial photoelectric properties of Agn/Bi2WO6 (001) (n=1, 2, 3, 4) hybrid photocatalyst. The parallel adsorption of Ag cluster leads to more energetic favorable structures due to stronger interfacial interactions. The positive charged Ag cluster may act as excited electron traps and facilitate the electron⿿hole separation. In particular, hybridization between Ag 5s and O 2p leads to the formation of isolated energy levels above the valence bands, and they become more dispersed with broader bandwidth with the increment of silver cluster size, which is responsible for the enhanced absorption in visible-light region. In the deep valence region, Ag 4d orbital turns more delocalized and hybrid with O 2p states as the cluster size increases, which contributes to more covalent bond feature of Ag⿿O. Moreover, optical spectra demonstrate obvious red-shifts of the absorption edge with the increment of silver content, which enhances efficiently the visible-light photocatalytic activities of Bi2WO6 (001). The study provides insights into the enhanced photocatalyic mechanism of Ag/Bi2WO6 (001) and aids in the design of noble metal loaded visible-light plasmonic photocatalyst.

Electron–Hole Pair Generation of the Visible-Light Plasmonic Photocatalyst Ag@AgCl: Enhanced Optical Transitions Involving Midgap Defect States of AgCl

We explored how the visible-light energy absorbed by noble-metal nanoparticles (NPs) is converted to electrons and holes in the semiconductor in a visible-light plasmonic photocatalyst by studying the representative system Ag@AgCl on the basis of density functional calculations and classical electrodynamics calculations. These calculations suggest that the energy transfer from the Ag NPs to the semiconductor AgCl requires the presence of midgap defect states in the semiconductor and that the surface plasmon resonance (SPR) of the Ag NPs strongly enhances the optical transitions of the semiconductor involving the defect states. We verified this suggestion experimentally by preparing Ag@AgCl samples possessing different degrees of bulk and surface defects and subsequently by carrying out photodegradation experiments using these samples.

A Facile, Template-Free Synthesis of AgCl Hierarchical Architectures: Precursors of Highly Efficient Visible-Light Plasmonic Photocatalysts of Ag@AgCl.

This paper describes a facile, template-free synthesis of AgCl hierarchical structures by a gas-liquid interfacial method and the morphology of AgCl (microrods or film) can be conveniently varied or controlled by changing the solvents of AgNO3 without using any surfactants. The AgCl composites were then photoreduced to form highly efficient visible-light plasmonic photocatalyst Ag@AgCl nanostructures. SEM, XRD, X-ray photoelectron spectroscopy, and UV/Vis diffuse reflectance spectroscopy were used to characterize the obtained product. The photocatalytic activity of the obtained product was evaluated by the photodegradation of methyl orange pollutant under visible-light irradiation, and it was found that Ag@AgCl microrods exhibited high visible-light photocatalytic activity and good stability.

Ag@graphene oxide nanocomposite as an efficient visible-light plasmonic photocatalyst for the degradation of organic pollutants: A facile green synthetic approach

We report a simple and effective supercritical route to decorate silver nanoparticles (Ag NPs) on graphene oxide (GO) using a commonly available and non-toxic glucose as a reducing agent. Transmission electron microscopy and energy-dispersive X-ray analysis confirmed that Ag NPs of size around 8–20 nm were coated on the GO surface under optimized experimental condition. Ag NPs on the GO surface were predominantly spherical in shape and well dispersed. The experimental results proved that the as-synthesized GO/Ag nanocomposite could be used as a highly efficient photocatalyst for the degradation of Rhodamine 123 dye and acetaldehyde under visible-light irradiation. The degradation results indicated that the photocatalytic performance of nanocomposite was greatly enhanced owing to the improved adsorption performance and separation efficiency of photo-generated carriers. The nanocomposite maintains a high level activity even after four times of recycle. Furthermore, the nanocomposite exhibited excellent antibacterial activity against gram-positive and gram-negative microorganisms.

A comparative study on the photocatalytic activities of two visible-light plasmonic photocatalysts: AgCl-SmVO4 and AgI-SmVO4 composites

Two novel plasmonic photocatalysts, AgCl-SmVO4 and AgI-SmVO4 composites, were prepared in this study. The two photocatalysts were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, transmission electron microscopy, and UV–vis diffuse reflectance spectroscopy. The results showed that the prepared samples have a similar phase composition. The two photocatalysts both consist of SmVO4, AgX (X=Cl, I), and Ag. However, their photocatalytic activities varied significantly. The photocatalytic testing result showed that the AgI-SmVO4 hybrid exhibited a photocatalytic activity approximately three times higher than that of AgCl-SmVO4 in the photodegradation of rhodamine B under visible-light illumination. In addition to the strong adsorption ability for dyes, the suitable band potential of AgI and SmVO4 was considered as another important reason for the higher photocatalytic activity of AgI-SmVO4. It was suggested that this excellent property would lead to a high separation efficiency of electron-hole pairs, improving the photocatalytic activity. This speculation was further verified by the photocurrent-time and active species trapping measurements.

Ag/AgBr/rGO nanocomposite: Synthesis and its application in photocatalysis

Ag/AgBr is a highly efficient visible-light plasmonic photocatalyst but suffers from severe aggregation of the particles. To settle this problem, we simply added a small amounts of graphene oxide (GO) to the Ag/AgBr reaction system. Expectedly, well monodispersed Ag/AgBr particles bonded on the rGO sheets (Ag/AgBr/rGO) was obtained, as observed by SEM. The adsorptive and photocatalytic activities of the as-prepared samples were investigated by degradation of RhB under visible light irradiation. Compared with pure Ag/AgBr, Ag/AgBr/rGO nanocomposite shows enhanced performance in both the adsorptive and photocatalytic activities.

Synthesis, characterization and photocatalytic activity of visible-light plasmonic photocatalyst AgBr-SmVO4

A novel composite photocatalyst AgBr-SmVO4 was synthesized by deposition method and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and UV–vis diffuse reflectance spectroscopy (DRS). The XRD, TEM, and XPS results indicated the prepared sample was actual a three-phase composite: SmVO4, AgBr, and Ag during the photocatalytic reaction. Due to the plasmon effect of Ag nanoparticles, the composite exhibited excellent photoabsorption ability for visible light. The photoelectrochemical measurement verified that the suitable band potential of AgBr and SmVO4 and the existence of metal Ag resulted in the high efficiency in charge separation of the composite. Photocatalytic degradation of rhodamine B (RhB) was carried out to evaluate the photocatalytic activity of AgBr/SmVO4 under visible-light irradiation. The composite presented excellent photocatalytic activity due to the synergetic effect of SmVO4, AgBr, and Ag nanoparticles. The photocatalytic activities of AgBr-SmVO4 were differently affected by the AgBr content in the catalyst, AgBr-SmVO4 amount, initial RhB concentration, and light sources. The highest degradation rate of 0.150min−1 was obtained on the 50wt% AgBr-SmVO4 sample, which was respectively 3.8 times and 25 times higher than that of AgBr and SmVO4 photocatalyst. It was found that O2− and Br0 acted as the main reactive species for the degradation of RhB under visible-light irradiation.

Ag@Cu2O Core-Shell Nanoparticles as Visible-Light Plasmonic Photocatalysts

Compared to pristine Cu2O nanoparticles (NPs), Ag@Cu2O core-shell NPs exhibit photocatalytic activity over an extended wavelength range because of the presence of localized surface plasmon resonance (LSPR) in the Ag core. The photocatalysis action spectra and transient absorption measurements show that the plasmonic energy is transferred from the metal to the semiconductor via plasmon-induced resonant energy transfer (PIRET) and direct electron transfer (DET) simultaneously, generating electron–hole pairs in the semiconductor. The LSPR band of Ag@Cu2O core-shell NPs shows a red-shift with an increase in the Cu2O shell thickness, extending the light absorption of Ag@Cu2O heterostructures to longer wavelengths. As a result, the photocatalytic activity of the Ag@Cu2O core-shell NPs is varied by modulation of the shell thickness on the nanometer scale. This work has demonstrated that the Ag@Cu2O core-shell heterostructure is an efficient visible-light plasmonic photocatalyst, which allows for tunable light ab...

One‐Step Hydrothermal Synthesis of Ag Nanoparticle Decorated Submicrometer‐Scale Spherical AgBr Colloids: A Highly Efficient Visible Light Plasmonic Photocatalyst for Degradation of Organic Dyes

Ag-AgBrCs are prepared by a novel one-step hydrothermal strategy. The resulting Ag-AgBrCs are prepared as a visible light plasmonic photocatalyst with high efficiency and for the degradation of organic dyes.

Visible-light plasmonic photocatalyst anchored on titanate nanotubes: a novel nanohybrid with synergistic effects of adsorption and degradation

A nanohybrid plasmonic photocatalyst, comprising Ag-AgX (X = Cl, Br, I) nanoparticles anchored on titanate nanotubes, was fabricated via a silver ion incorporation process followed by hydrogen halide injection and light-irradiation. The Ag-AgX-titanate nanotubes (Ag-AgX-TNT) hybrid with a high surface area could synergistically adsorb and degrade methylene blue (MB) under visible light, viz., the titanate nanotubes adsorb MB onto their surfaces, which aids the degradation of MB by Ag-AgX nanoparticles. The excellent degradation performance of Ag-AgX under visible light originated from its localized surface plasmonic resonance effect. Therefore, this integrated silver halides/titanate hybrid can efficiently degrade MB dye, and shows good potential for waste water treatment utilizing solar irradiation.

Graphene Oxide Enwrapped Ag/AgX (X = Br, Cl) Nanocomposite as a Highly Efficient Visible-Light Plasmonic Photocatalyst

In this paper, we have reported that well-defined graphene oxide (GO) enwrapped Ag/AgX (X = Br, Cl) nanocomposites, which are composed of Ag/AgX nanoparticles and gauze-like GO nanosheets, could be facilely fabricated via a water/oil system. We have shown that thus-synthesized GO-based hybrid nanocomposites could be used as a stable plasmonic photocatalyst for the photodegradation of methyl orange (MO) pollutant under visible-light irradiation. Compared with the corresponding bare Ag/AgX nanospecies, the GO-involved nanocomposites (Ag/AgX/GO) display distinctly enhanced photocatalytic activities. The hybridization of Ag/AgX with GO nanosheets causes the nice adsorptive capacity of Ag/AgX/GO to MO molecules, the smaller size of the Ag/AgX nanoparticles in Ag/AgX/GO, the facilitated charge transfer, and the suppressed recombination of electron-hole pairs in Ag/AgX/GO. It is suggested that these multifactors, resulting from the hybridization of GO, contribute to the enhanced photocatalytic performance observed from Ag/AgX/GO. The investigation likely opens up new possibilities for the development of original yet highly efficient and stable GO-based plasmonic photocatalysts that utilize visible light as an energy source.