Strong localized surface plasmon resonance effects of Ag/TiO2 core-shell nanowire arrays in UV and visible light for photocatalytic activity

Density-controlled electrochemical synthesis of ZnO nanowire arrays using nanotextured cathode

Zinc oxide (ZnO) nanowires fabricated via wet chemical synthesis on flexible polymer substrates are inherently unstable against mechanical bending stress because of their high density and weak adhesion to the substrate. We introduce a novel method for controlling the density of such ZnO nanowire arrays using a three-dimensional corrugated metal substrate. These metal substrates, featuring extruded and recessed patterns fabricated via nanoimprint lithography, were employed as cathodes during the electrochemical deposition of ZnO nanowire arrays. The ZnO nanowire arrays synthesized on the patterned metal thin film exhibited smaller diameters and lower densities compared to those on non-patterned metal films. This reduction in density can be attributed to aligned nucleation and limited growth on the patterned metal surface. Crucially, ZnO nanowires synthesized on patterned metal substrates displayed remarkable mechanical robustness against external forces, a direct consequence of their reduced density. In contrast, nanowires synthesized on non-patterned metal substrates were broken under mechanical bending. Detailed morphological analyses performed after mechanical bending tests confirm that ZnO nanowires synthesized on nanoimprinted metal electrodes exhibited enhanced mechanical characteristics compared to those on non-patterned metal electrodes. These findings clearly demonstrate the promise of utilizing density-controlled ZnO nanowires in piezoelectric devices.

Radiation synthesis of MXene/Ag nanoparticle hybrids for efficient photothermal conversion of polyurethane films

Flexible conductive films based on light-to-heat conversion are promising for the next-generation electronic devices. A flexible waterborne polyurethane composite film (PU/MA) with excellent photothermal conversion performance was obtained by combination of PU and silver nanoparticle decorated MXene (MX/Ag). The silver nanoparticles (AgNPs) uniformly decorated on the MXene surface by γ-ray irradiation induced reduction. Because of the synergistic effect of MXene with outstanding light-to-heat conversion efficiency and the AgNPs with plasmonic effect, the surface temperature of the PU/MA-II (0.4%) composite with lower MXene content increased from room temperature to 60.7 °C at 5 min under 85 mW cm^-2 light irradiation. Besides, the tensile strength of PU/MA-II (0.4%) increased from 20.9 MPa (pure PU) to 27.5 MPa. The flexible PU/MA composite film shows great potential in the field of thermal management of flexible wearable electronic devices.

Novel cubical Ag(NP) decorated titanium dioxide supported bentonite thin film in the efficient removal of bisphenol A using visible light

The persistent endocrine-disrupting chemical bisphenol A is posing serious health concerns; hence, it is known to be an emerging and potential water contaminant. The present investigation aims to synthesize novel cubical Ag(NP) decorated titanium dioxide-supported bentonite (Ag/TiO₂@Clay) nanocomposite using a novel synthetic process. The nanocomposite materials were characterized by several analytical methods viz., transmission electron microscopy (TEM), X-ray diffraction (XRD) analyses, energy-dispersive X-ray spectroscopy (EDX), atomic force microscopy (AFM), scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) and diffuse reflectance spectroscopy (DRS). Further, the photocatalytic removal of bisphenol A was conducted utilizing the thin film catalyst under the LED (light emitting diode; visible light) and UV-A (ultra violet-A) light sources. The parametric studies solution pH (6.0-12.0), pollutant concentrations (1.0-20.0 mg/L), and the interaction of several scavengers and co-existing ions are studied extensively to demonstrate the insights of the removal mechanism. The mineralization of bisphenol A and repeated use of the thin film catalyst showed the potential usage of photocatalysts in the devised large-scale operations. Similarly, the natural matrix treatment was performed to evaluate the suitability of the process for real implications.

Novel nanocomposite thin film in the efficient removal of antibiotics using visible light: Insights of photocatalytic reactions and stability of thin film in real water implications

Novel clay (bentonite) supported Ag⁰ nanoparticles (NPs) doped TiO₂ nanocomposite (Clay/TiO₂/Ag⁰(NPs)) thin film was obtained by using template synthesis method. The nanocomposite material is decorated with cubical Ag⁰(NPs) and utilised successfully in the photocatalytic degradation of tetracycline (TC) and sulfamethazine (SMZ) from aqueous solutions utilizing visible light and UV-A radiations. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET), X-ray photoelectron spectroscopy (XPS) analyses were used to characterise the nanocomposite materials. Diffusion reflectance spectroscopy (DRS) was utilised to determine the bandgap energies of the materials and also to confirm that Ag⁰(NPs) was successfully doped with TiO₂. The nanocomposite material showed highly efficient photocatalytic activity for the breaking down of TC/SMZ under visible light irradiation by the enhanced electron-hole separation and adsorption of antibiotics at the vicinity of the catalyst. The oxidative degradation of TC/SMZ were shown to be highly dependent on the pH, initial concentration of TC/SMZ, and various co-existing ions. Reusability test of Clay/Ag⁰(NPs)/TiO₂ nanocomposite revealed that the activity did not decline with repeated use. Treatment of TC and SMZ in real water system further enhanced the application potential of the novel catalysts for the treatment of full-scale wastewater polluted with these antibiotics.

Solution combustion synthesis: the relevant metrics for producing advanced and nanostructured photocatalysts

The current developments and progress in energy and environment-related areas pay special attention to the fabrication of advanced nanomaterials via green and sustainable paths to accomplish chemical circularity. The design and preparation methods of photocatalysts play a prime role in determining the structural, surface characteristics and optoelectronic properties of the final products. The solution combustion synthesis (SCS) technique is a relatively novel, cost-effective, and efficient method for the bulk production of nanostructured materials. SCS-fabricated metal oxides are of great technological importance in photocatalytic, environmental and energy applications. To date, the SCS route has been employed to produce a large variety of solid materials such as metals, sulfides, carbides, nitrides and single or complex metal oxides. This review intends to provide a holistic perspective of the different steps involved in the chemistry of SCS of advanced photocatalysts, and pursues several SCS metrics that influence their photocatalytic performances to establish a feasible approach to design advanced photocatalysts. The study highlights the fundamentals of SCS and the importance of various combustion parameters in the characteristics of the fabricated photocatalysts. Consequently, this work deals with the design of a concise framework to link the fine adjustment of SCS parameters for the development of efficient metal oxide photocatalysts for energy and environmental applications.

Plasmonic Hybrid Nanostructures in Photocatalysis: Structures, Mechanisms, and Applications

(Sun)Light is an abundantly available sustainable source of energy that has been used in catalyzing chemical reactions for several decades now. In particular, studies related to the interaction of light with plasmonic nanostructures have been receiving increased attention. These structures display the unique property of localized surface plasmon resonance, which converts light of a specific wavelength range into hot charge carriers, along with strong local electromagnetic fields, and/or heat, which may all enhance the reaction efficiency in their own way. These unique properties of plasmonic nanoparticles can be conveniently tuned by varying the metal type, size, shape, and dielectric environment, thus prompting a research focus on rationally designed plasmonic hybrid nanostructures. In this review, the term "hybrid" implies nanomaterials that consist of multiple plasmonic or non-plasmonic materials, forming complex configurations in the geometry and/or at the atomic level. We discuss the synthetic techniques and evolution of such hybrid plasmonic nanostructures giving rise to a wide variety of material and geometric configurations. Bimetallic alloys, which result in a new set of opto-physical parameters, are compared with core-shell configurations. For the latter, the use of metal, semiconductor, and polymer shells is reviewed. Also, more complex structures such as Janus and antenna reactor composites are discussed. This review further summarizes the studies exploiting plasmonic hybrids to elucidate the plasmonic-photocatalytic mechanism. Finally, we review the implementation of these plasmonic hybrids in different photocatalytic application domains such as H₂ generation, CO₂ reduction, water purification, air purification, and disinfection.

Exploring the modulation mechanism of the LSPR effect of Cu periodic nanosphere arrays to promote the performance of TiO2 photoelectrodes

Cu periodic nanosphere arrays can greatly promote the photoelectrochemical performance of TiO2 photoelectrodes by localized surface plasmon resonance effects, multiple scattering and coupling effects.

One-dimensional Ag-CoNi nanocomposites modified with amorphous Sn(OH)2/SnO2 shells for broadband microwave absorption

High-performance microwave absorption absorbers play important roles in the fields of radar stealth, electromagnetic protection, and antenna technology. In this work, high aspect-ratio Ag nanowires were decorated with magnetic CoNi nanoparticles via a PVP-induced solvothermal method, and then amorphous Sn(OH)₂/SnO₂ shells were introduced through an in-situ oxidative hydrolysis method, successfully preparing Ag-CoNi@Sn(OH)₂/SnO₂ composites. The morphology and ingredient of composites were ascertained by SEM, TEM, XRD, EDX, and XPS. As Ag-CoNi nanocomposites are coated by Sn(OH)₂/SnO₂ shells, the minimum reflection loss value is decreased from -31.7 dB (10.1 GHz) to -37.8 dB (6.4 GHz), and the maximum effective absorption bandwidth is extended from 3.9 GHz (10.3-14.2 GHz) to 5.8 GHz (10.7-16.5 GHz). Analyses of electromagnetic parameters reveal the possible mechanisms, involving surface plasma resonance, conductive loss, interfacial polarization, dipole polarization, exchange resonance, eddy current effect, multiple reflection and scattering. Thus, Ag nanowires modified with CoNi nanoparticles and amorphous Sn(OH)₂/SnO₂ shells can effectively balance the impedance matching and attenuation capability. It is a new strategy to achieve broadband microwave absorbers.

Template-Free and Surfactant-Free Synthesis of Selective Multi-Oxide-Coated Ag Nanowires Enabling Tunable Surface Plasmon Resonance

Without using templates, seeds and surfactants, this study successfully prepared multi-oxide-layer coated Ag nanowires that enable tunable surface plasmon resonance without size or shape changes. A spontaneously grown ultra-thin titania layer onto the Ag nanowire surface causes a shift in surface plasmon resonance towards low energy (high wavelength) and also acts as a preferential site for the subsequent deposition of various oxides, e.g., TiO₂ and CeO₂. The difference in refractive indices results in further plasmonic resonance shifts. This verifies that the surface plasma resonance wavelength of one-dimensional nanostructures can be adjusted using refractive indices and shell oxide thickness design.

3D Layer-By-Layer Pd-Containing Nanocomposite Platforms for Enhancing the Performance of Hydrogen Sensors

Herein, a nanowelding technique is adopted to fabricate three-dimensional layer-by-layer Pd-containing nanocomposite structures with special properties. Nanowires fabricated from noble metals (Pd, Pt, Au, and Ag) were used to prepare Pd-Pd nanostructures and Pd-Au, Pd-Pt, Pd-Ag, and Pd-Pt-Au nanocomposite structures by controlling the welding temperature. The recrystallization behavior of the welded composite materials was observed and analyzed. In addition, their excellent mechanical and electrical properties were confirmed by performing 10,000 bending test cycles and measuring the resistances. Finally, flexible and wearable nanoheaters and gas sensors were fabricated using our proposed method. In comparison with conventional techniques, our proposed method can not only easily achieve sensors with a large surface area and flexibility but also improve their performance through the addition of catalyst metals. A gas sensor fabricated using the Pd-Au nanocomposites demonstrated 3.9-fold and 1.1-fold faster H₂ recovery and response, respectively, than a pure Pd-Pd gas sensor device. Moreover, the Pd-Ag nanocomposite exhibited a high sensitivity of 5.5% (better than that of other fabricated gas sensors) for 1.6% H₂ concentration. Therefore, we believe that the fabricated nanocomposites appear promising for wide applications in wearable gas sensors, flexible optical devices, and flexible catalytic devices.

Influence of surfactant, particle size and dispersion medium on surface plasmon resonance of silver nanoparticles

Clear influence of particle size, surfactants and dispersion medium on surface plasmon resonance (SPR) features of Ag nanoparticles (NPs), synthesized in thermal decomposition method, in the broad range of ultraviolet (UV) radiation, critical for many potential applications such as a photocatalyst, UV-sensor and detector, has been demonstrated here. It involves adsorbate coverage, interparticle distance or agglomeration, surface charge density and solvent refractive index (µ). NP agglomeration and surface charge density in solvents of varying µ have been studied systematically through zeta-potential (ζ) and hydrodynamic diameter (HD) using dynamic light scattering (DLS). The main SPR feature found at 316 nm in 31.5 nm NPs shifts to 320 nm in 15.1 nm NPs. The peak at 320 nm in air shifts to 259, 261 and 277 nm in polar solvent methanol, deionized water and ethanol, respectively and to 255, 275 and 282 nm in non-polar solvent n-hexane, benzene and toluene, respectively. In general, the decrease in particle size and increase in µ of solvents show red-shift. Curiously, a number of peaks up to seven in these solvents that are attributed to charge-transfer mechanism and change in inter-particle interaction of the NPs turning from a single peak of SPR in air has been observed for the first time. A model for re-adjustment of Fermi level (E _F) of Ag NP and the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) to explain them has also been used. Moreover, the Drude model for shift in the position of SPR in these NPs is only applicable in non-polar solvents, not in polar solvents. Such novel features will be potential candidates for various applications.

TiO2 nanosheet/NiO nanorod hierarchical nanostructures: p-n heterojunctions towards efficient photocatalysis

TiO₂ nanosheet/NiO nanorod heterojunction hybrids have been developed through a hydrothermal route, where NiO nanorods (size: 5 nm in diameter and 20-40 nm in length) are deposited at the {0 0 1} facet of anatase TiO₂ nanosheets. The photocatalysts were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD), N₂ adsorption-desorption analysis, UV-vis spectroscopy, X-ray photoelectron spectroscopy (XPS), photoluminescence spectroscopy and time-resolved fluorescence. The TiO₂/NiO photocatalysts exhibited good photocatalytic activities towards the degradation of methyl blue (MB) and phenol, and hydrogen generation efficiency under visible light irradiation. The maximum rate constant can be reached 0.0279 min^-1 and 0.0135 min^-1 respectively, which are about 12 and 10 times higher than that of TiO₂ nanosheets. And the hydrogen generation efficiency is 10 times higher than physical mixing of TiO₂ and NiO. Photocatalytic degradation efficiency remains more than 90% after 6 times cycle dye degradation, and the H₂ production efficiency is almost the same after four cycles, suggesting good stability and reusability. The enhanced photocatalytic activities are associated with the rational design of TiO₂/NiO hierarchical heterojunctions which ensues high photogenerated charge separation efficiency. With the improved photocatalytic performance, the TiO₂/NiO heterojunction hybrids are expected to be potential photocatalysts in environmental and energy related areas.

Nanotransfer Printing on Textile Substrate with Water-Soluble Polymer Nanotemplate

The growing interest in wearable devices has drawn increased attention to smart textiles, and various transfer methods have therefore been introduced to realize the desired functions using textiles as substrates. However, the existing transfer techniques are not suited for the production of sophisticated nanoscale patterns on textiles, as textile roughness and difficulty of precise pattern size control hinder miniaturization, deteriorate device performance, and complicate the use of optical phenomena such as surface plasmon resonance. To address these limitations, we have developed a method based on simple dissolution of a water-soluble nanopatterned polymer film for the facile transfer of nanostructures of on-film-deposited functional materials onto textile substrates. The above method tolerates a variety of functional materials, e.g., metals and SiO₂, and nano/microscale structures, e.g., nanoscale lines, dots, holes, and mesh patterns with a minimum pattern width of 50 nm. The proposed technique is employed to fabricate a palladium nanoscale line array (utilized as a highly sensitive and selective hydrogen sensor) and is shown to be suitable for the production of security patterns on textiles, as it allows the printing of complex nanostructure patterns with electrical and optical functionalities.

Photocatalytic debromination of polybrominated diphenyl ethers (PBDEs) on metal doped TiO2 nanocomposites: Mechanisms and pathways

Nanoparticles of four noble metal doped titanium dioxide (i.e., Pd/TiO₂, Ag/TiO₂, Pt/TiO₂ and Cu/TiO₂) were synthesized and investigated for their effectiveness to degrade polybrominated diphenyl ethers (PBDEs) under UV light. All the investigated noble metal additives can greatly enhance the performance of TiO₂ to degrade 2,2',4',4'-tetrabromodiphenyl ether (BDE-47). However, the debromination pathways of BDE-47 in Ag/TiO₂ and Cu/TiO₂ systems are just contrary to those in Pd/TiO₂ and Pt/TiO₂ systems, and there was an induction period in the former systems but not in the latter systems. The hydrogenation experiment suggests a direct H-atom transfer mechanism in Pd/TiO₂ and Pt/TiO₂ systems, while in Ag/TiO₂ and Cu/TiO₂ systems, electron transfer is still the dominant mechanism. Electronic method was applied to explain why BDE-47 exhibit different debromination pathways based on different degradation mechanism. In addition, oxygen was proved to be able to capture both electrons and H atoms, and thus can greatly inhibit the degradation of PBDEs in all investigated systems. Finally, the merit and demerit of each metal doped TiO₂ were discussed in detail, including the reactivity, stability and the generation of byproducts. We proposed our study greatly enhance our understanding on the mechanisms of PBDE degradation in various metal doped TiO₂ systems.

Characterization and Effect of Ag(0) vs. Ag(I) Species and Their Localized Plasmon Resonance on Photochemically Inactive TiO2

Commercial TiO2 (anatase) was successfully modified with Ag nanoparticles at different nominal loadings (1%–4%) using a liquid impregnation method. The prepared materials retained the anatase structure and contained a mixture of Ag0 and AgI species. Samples exhibited extended light absorption to the visible region. The effect of Ag loading on TiO2 is studied for the photocatalytic reduction of CO2 to CH4 in a gas–solid process under high-purity conditions. It is remarkable that the reference TiO2 used in this work is entirely inactive in this reaction, but it allows for studying the effect of Ag on the photocatalytic process in more detail. Only in the case of 2% Ag/TiO2 was the formation of CH4 from CO2 observed. Using different light sources, an influence of the localized surface plasmon resonance (LSPR) effect of Ag is verified. A sample in which all Ag has been reduced to the metallic state was less active than the respective sample containing both Ag0 and Ag+, indicating that a mixed oxidation state is beneficial for photocatalytic performance. These results contribute to a better understanding of the effect of metal modification of TiO2 in photocatalytic CO2 reduction.

Carbon/TiO2/Fe2O3 hybrid shells as efficient visible light photocatalysts

Mesoporous C/TiO₂/Fe₂O₃ hollow hybrids with TiO₂/Fe₂O₃ p–n heterojunctions and electrically conductive carbon show high photocatalytic performance.

Prompting peroxidase-like activity of gold nanorod composites by localized surface plasmon resonance for fast colorimetric detection of prostate specific antigen

The interaction between incident light and surface electrons in conductive nanoparticles produces localized plasmon oscillations with a resonant frequency that strongly depends on the composition, size, geometry, and dielectric environment. Hybrid heterostructure materials combining two or more materials in one structure represent a powerful way to achieve unique properties and multifunctionality compared to those of the individual nanoparticle components. Hybrid gold nanorods and gold nanoclusters (GNR/AuNCs) heterostructures prepared by intimate integration of GNRs with AuNCs exhibit both localized surface plasmon resonance (LSPR) property and peroxidase-like activity. It is found that the catalytic activity of the AuNC/GNR heterostructure could be remarkably enhanced by LSPR induced by photon-plasmon coupling in the visible to near-infrared (NIR) region. Meanwhile, the catalytic activity of enzyme-like AuNC/GNRs may be regulated by immunoreactions to realize specific recognition of a target analyte. Accordingly, a fast colorimetric assay within 5 min for the detection of prostate specific antigen (PSA) was developed based on a AuNC/GNRs heterostructure mask regulated by the target molecule under photon-plasmon coupling. The color intensity is inversely proportional to the PSA concentration, and quantitative analysis may be achieved in a range of 10 and 200 pg mL-1. This sensor was practically applied to detect PSA levels in prostate cancer serum samples and the determined values agreed well with those measured by the hospital using standard methods. This indicates that the AuNC/GNRs heterostructure-based assay has high accuracy for the analysis of practical samples. Moreover, the new method has the advantages of very fast determination and low sample volume requirements.

Composition-adjustable Ag-Au substitutional alloy microcages enabling tunable plasmon resonance for ultrasensitive SERS

Engineering the surface plasmon resonance (SPR) properties is a critical issue for improving device performance in the fields of plasmonics, nanophotonics, optoelectronics, and electrochemistry. Here, we demonstrated a programmable manipulation of the surface plasmon resonance (SPR) effect using composition-adjustable Ag-Au substitutional alloy microcages (SAMCs) through a facile NaBH4-cooperative galvanic replacement reaction. The SPR frequency of the Ag-Au SAMCs can be continuously and exquisitely manipulated without resonance damping or broadening via accurate adjustment of the elemental composition distribution at the perfect homogeneity on the atomic-level. Significantly, both the tunable SPR frequency and excellent chemical stability synergistically endow the hollow Ag-Au SAMCs with excellent SERS sensitivity and reproducibility, which lays a foundation for the realization of trace detection of thiram at an ultralow concentration of 1 × 10-12 M. This strategy is a promising candidate for efficient promotion of the SERS activity for metal-based substrates.

Mechanistic insights into plasmonic photocatalysts in utilizing visible light

The utilisation of sunlight as an abundant and renewable resource has motivated the development of sustainable photocatalysts that can collectively harvest visible light. However, the bottleneck in utilising the low energy photons has led to the discovery of plasmonic photocatalysts. The presence of noble metal on the plasmonic photocatalyst enables the harvesting of visible light through the unique characteristic features of the noble metal nanomaterials. Moreover, the formation of interfaces between noble metal particles and semiconductor materials further results in the formation of a Schottky junction. Thereby, the plasmonic characteristics have opened up a new direction in promoting an alternative path that can be of value to the society through sustainable development derived through energy available for all for diverse applications. We have comprehensively prepared this review to specifically focus on fundamental insights into plasmonic photocatalysts, various synthesis routes, together with their strengths and weaknesses, and the interaction of the plasmonic photocatalyst with pollutants as well as the role of active radical generation and identification. The review ends with a pinnacle insight into future perspectives regarding realistic applications of plasmonic photocatalysts.

Three-dimensional plasmonic Ag/TiO2 nanocomposite architectures on flexible substrates for visible-light photocatalytic activity

In this study, a periodic three-dimensional (3D) Ag/TiO₂ nanocomposite architecture of nanowires was fabricated on a flexible substrate to enhance the plasmonic photocatalytic activity of the composite. Layer-by-layer nanofabrication based on nanoimprint lithography, vertical e-beam evaporation, nanotransfer, and nanowelding was applied in a new method to create different 3D Ag/TiO₂ nanocomposite architectures. The fabricated samples were characterized by scanning electron microscopy, transmission electron microscopy, focused ion-beam imaging, X-ray photoelectron spectrometry, and UV–visible spectroscopy. The experiment indicated that the 3D nanocomposite architectures could effectively enhance photocatalytic activity in the degradation of methylene blue solution under visible light irradiation. We believe that our method is efficient and stable, which could be applied to various fields, including photocatalysis, solar energy conversion, and biotechnology.

Dielectrophoretic-Assembled Single and Parallel-Aligned Ag Nanowire-ZnO-Branched Nanorod Heteronanowire Ultraviolet Photodetectors

The branched hierarchical heteronanowires have been widely studied for optoelectronics application because of their unique electronic and photonic performances. Here, we successfully synthesized Ag nanowire-ZnO-branched nanorod heteronanowires based on an improved hydrothermal method. Then we fabricated single heteronanowire across a Au electrode pair with different gap widths and parallel-aligned heteronanowires on a Au interdigitated electrode with a dielectrophoresis method, indicating the flexibility and operability of the dielectrophoresis assembly method. Increased photocurrent and shortened response time could be obtained by air-annealing and Ar-plasma post-treatments. A large responsivity of 2.5 A W^-1 and a linear dynamic range of 74 dB could be obtained, indicating stable responsivity for both weak and strong illumination. The excellent photoresponse performance is attributed to the structure superiority of heteronanowires. The proposed strategy of dielectrophoresis-assembled heteronanowires provides a new opportunity to design and fabricate hierarchical nanostructure photodetectors.

Synergistic effect of upconversion and plasmons in NaYF4:Yb3+, Er3+, Tm3+@TiO2–Ag composites for MO photodegradation

Structure-based rational design of photocatalysts to enable combination of nanocomponents of radically different properties for enhanced solar energy utilization is a very challenging task.

Carbon-Incorporated NiO/TiO2 Mesoporous Shells with p-n Heterojunctions for Efficient Visible Light Photocatalysis

Carbon-incorporated mesoporous NiO/TiO₂ (NiO/TiO₂/C) hybrid shells as low-cost and highly efficient visible light photocatalysts have been developed. The NiO/TiO₂/C hybrid shells were synthesized by choosing polystyrene nanospheres as templates, followed by TiO₂ and NiO coating, and finally the calcination post-treatment to carbonize PS with the aid of metal oxides. Polystyrene nanospheres serve dual purposes as both a template to ensure the hollow structure and the electrically conductive graphite carbon source. Evaluation of their photocatalytic activity by organic pollutes (rhodamine B, methylene blue, and phenol) degradation and H₂ production under visible light demonstrated the superior photocatalytic performance, thanks to the enhanced visible-light absorption and exciton separation associated with the incorporation of electrically conductive graphite carbon.

Visible light assisted electro–photo synergistic catalysis of heterostructured Pd–Ag NPs/graphene for methanol oxidation

Heterostructured Pd-Ag/GNs catalytic performances for MOR are significantly improved by visible light irradiation: (a) without irradiation, (b) under irradiation.

UV-visible and near-infrared active NaGdF4:Yb:Er/Ag/TiO2 nanocomposite for enhanced photocatalytic applications

A near infra-red (NIR) active NaGdF₄:Yb:Er/Ag/TiO₂ nanocomposite photocatalyst was successfully synthesized by a one-pot thermal decomposition method.

Growth Mechanism and Electrical and Magnetic Properties of Ag-Fe₃O₄ Core-Shell Nanowires

One-dimensional Ag-Fe3O4 core-shell heteronanowires have been synthesized by a facile and effective coprecipitation method, in which silver nanowires (AgNWs) were used as the nucleation site for growth of Fe3O4 in aqueous solution. The size and morphology control of the core-shell nanowires were achieved by simple adjustments of reaction conditions including FeCl3/FeCl2 concentration, poly(vinylpyrrolidone) (PVP) concentration, reaction temperature, and time. It was found that the Fe3O4 shell thickness could be tuned from 6 to 76 nm with the morphology variation between nanopheres and nanorods. A possible growth mechanism of Ag-Fe3O4 core-shell nanowires was proposed. First, the C═O derived from PVP on the surface of AgNWs provided nucleation points and in situ oxidation reaction between AgNWs and FeCl3/FeCl2 solution promoted the accumulation of Fe(3+) and Fe(2+) on the AgNWs surface. Second, Fe3O4 nanoparticles nucleated on the AgNWs surface. Lastly, Fe3O4 nanoparticles grew on the AgNWs surface by using up the reagents. Higher FeCl3/FeCl2 concentration or higher temperature led to faster nucleation and growth, resulting in the formation of Fe3O4 nanorods, whereas lower concentration or lower temperature resulted in slower nucleation and growth, leading to the formation of Fe3O4 nanospheres. Furthermore, the Ag-Fe3O4 core-shell nanowires exhibited good electrical properties and ferromagnetic properties at room temperature. Particularly, the magnetic saturation values (Ms) increased from 5.7 to 26.4 emu g(-1) with increasing Fe3O4 shell thickness from 9 to 76 nm. This growth of magnetic nanoparticles on 1D metal nanowires is meaningful from both fundamental and applied perspectives.

New facile synthesis of one-dimensional Ag@TiO2 anatase core–shell nanowires for enhanced photocatalytic properties

One-dimensional Ag@TiO₂ anatase core–shell nanowires are fabricated and exhibit high photocatalytic activity for degrading organic contaminants under visible-light irradiation.