Au@TiO Core-Shell Nanoparticles with Nanometer-Controlled Shell Thickness for Balancing Stability and Field Enhancement in Plasmon-Enhanced Photocatalysis.

Plasmonic core-shell nanostructures can make photocatalysis more efficient for several reasons. The shell imparts stability to the nanoparticles, light absorption is expanded, and electron-hole pairs can be separated more effectively, thus reducing recombination losses. The synthesis of metal@TiO core-shell nanoparticles with nanometer control over the shell thickness and understanding its effect on the resulting photocatalytic efficiency still remains challenging.

AuCu bimetallic nanocluster-modified titania nanotubes for photoelectrochemical water splitting: composition-dependent atomic arrangement and activity.

The photoelectrochemical (PEC) water splitting reaction of bimetallic AuCu ( = 1, 0.75, 0.5, 0.

Surface modification of mesostructured cellular foam to enhance hydrogen storage in binary THF/H clathrate hydrate.

This study introduces solid-state tuning of a mesostructured cellular foam (MCF) to enhance hydrogen (H) storage in clathrate hydrates. Grafting of promoter-like molecules (, tetrahydrofuran) at the internal surface of the MCF resulted in a substantial improvement in the kinetics of formation of binary H-THF clathrate hydrate. Identification of the confined hydrate as sII clathrate hydrate and enclathration of H in its small cages was performed using XRD and high-pressure H NMR spectroscopy respectively.

Black titania by sonochemistry: A critical evaluation of existing methods.

In the field of photocatalysis, the fabrication of black titania is a booming topic, as it offers a system with improved solar light harvesting properties and increased overall efficiency. The darkening of white TiO powders can be ascribed to surface hydroxylation, oxygen vacancies, Ti centres, or a combination thereof. A handful of studies suggests these defects can be conveniently introduced by acoustic cavitation, generated during sonochemical treatment of pristine TiO powders.

Gas phase deposition of well-defined bimetallic gold-silver clusters for photocatalytic applications.

Cluster beam deposition is employed for fabricating well-defined bimetallic plasmonic photocatalysts to enhance their activity while facilitating a more fundamental understanding of their properties. AuAg clusters with compositions ( = 0, 0.1, 0.

A Review on Self-Assembly of Colloidal Nanoparticles into Clusters, Patterns, and Films: Emerging Synthesis Techniques and Applications.

The colloidal synthesis of functional nanoparticles has gained tremendous scientific attention in the last decades. In parallel to these advancements, another rapidly growing area is the self-assembly or self-organization of these colloidal nanoparticles. First, the organization of nanoparticles into ordered structures is important for obtaining functional interfaces that extend or even amplify the intrinsic properties of the constituting nanoparticles at a larger scale.

Benchmarking the Photocatalytic Self-Cleaning Activity of Industrial and Experimental Materials with .

Various industrial surface materials are tested for their photocatalytic self-cleaning activity by performing the ISO 27448:2009 method. The samples are pre-activated by UV irradiation, fouled with oleic acid and irradiated by UV light. The degradation of oleic acid over time is monitored by taking water contact angle measurements using a contact angle goniometer.

Recent Trends in Plasmon-Assisted Photocatalytic CO Reduction.

Direct photocatalytic reduction of CO has become an highly active field of research. It is thus of utmost importance to maintain an overview of the various materials used to sustain this process, find common trends, and, in this way, eventually improve the current conversions and selectivities. In particular, CO photoreduction using plasmonic photocatalysts under solar light has gained tremendous attention, and a wide variety of materials has been developed to reduce CO towards more practical gases or liquid fuels (CH , CO, CH OH/CH CH OH) in this manner.

Sunlight-Powered Reverse Water Gas Shift Reaction Catalysed by Plasmonic Au/TiO Nanocatalysts: Effects of Au Particle Size on the Activity and Selectivity.

This study reports the low temperature and low pressure conversion (up to 160 °C, = 3.5 bar) of CO and H to CO using plasmonic Au/TiO nanocatalysts and mildly concentrated artificial sunlight as the sole energy source (up to 13.9 kW·m = 13.

Photocatalytic soot degradation under UV and visible light.

Particulate matter is one of the most persistent global air pollutants that is causing health problems, climate disturbance and building deterioration. A sustainable technique that is able to degrade soot using (sun)light is photocatalysis. Currently, research on photocatalytic soot oxidation focusses on large band gap TiO-based photocatalysts and thus requires the use of UV light.

Probing oxygen activation on plasmonic photocatalysts.

In this work we present an assay to probe the oxygen activation rate on plasmonic nanoparticles under visible light. Using a superoxide-specific XTT molecular probe, the oxygen activation rate on bimetallic gold-silver "rainbow" nanoparticles with a broadband visible light (> 420 nm) response, is determined at different light intensities by measuring its conversion into the colored XTT-formazan derivate. A kinetic model is applied to enable a quantitative estimation of the rate constant, and is shown to match almost perfectly with the experimental data.

Plasmon resonance of gold and silver nanoparticle arrays in the Kretschmann (attenuated total reflectance) vs. direct incidence configuration.

While the behaviour of plasmonic solid thin films in the Kretschmann (also known as Attenuated Total Reflection, ATR) configuration is well-understood, the use of discrete nanoparticle arrays in this optical configuration is not thoroughly explored. It is important to do so, since close packed plasmonic nanoparticle arrays exhibit exceptionally strong light-matter interactions by plasmonic coupling. The present work elucidates the optical properties of plasmonic Au and Ag nanoparticle arrays in both the direct normal incidence and Kretschmann configuration by numerical models, that are validated experimentally.

Photoelectrochemical Behavior of Phthalocyanine-Sensitized TiO in the Presence of Electron-Shuttling Mediators.

Dye-sensitized TiO has found many applications for dye-sensitized solar cells (DSSC), solar-to-chemical energy conversion, water/air purification systems, and (electro)chemical sensors. We report an electrochemical system for testing dye-sensitized materials that can be utilized in photoelectrochemical (PEC) sensors and energy conversion. Unlike related systems, the reported system does not require a direct electron transfer from semiconductors to electrodes.

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.

Layer-by-Layer-Stabilized Plasmonic Gold-Silver Nanoparticles on TiO: Towards Stable Solar Active Photocatalysts.

To broaden the activity window of TiO, a broadband plasmonic photocatalyst has been designed and optimized. This plasmonic 'rainbow' photocatalyst consists of TiO modified with gold-silver composite nanoparticles of various sizes and compositions, thus inducing a broadband interaction with polychromatic solar light. However, these nanoparticles are inherently unstable, especially due to the use of silver.

Selectivity in the Ligand Functionalization of Photocatalytic Metal Oxide Nanoparticles for Phase Transfer and Self-Assembly Applications.

The functionalization of photocatalytic metal oxide nanoparticles of TiO , ZnO, WO and CuO with amine-terminated (oleylamine) and thiol-terminated (dodecane-1-thiol) alkyl-chain ligands was studied under ambient conditions. A high selectivity was observed in the binding specificity of a ligand towards nanoparticles of these different oxides. It was observed that oleylamine binds stably to only TiO and WO , whereas dodecane-1-thiol binds stably only to ZnO and CuO.

Unraveling Structural Information of Turkevich Synthesized Plasmonic Gold-Silver Bimetallic Nanoparticles.

For the synthesis of gold-silver bimetallic nanoparticles, the Turkevich method has been the state-of-the-art method for several decades. It is presumed that this procedure results in a homogeneous alloy, although this has been debatable for many years. In this work, it is shown that neither a full alloy, nor a perfect core-shell particle is formed but rather a core-shell-like particle with altering metal composition along the radial direction.

Characterization of silver-polymer core-shell nanoparticles using electron microscopy.

Silver-polymer core-shell nanoparticles show interesting optical properties, making them widely applicable in the field of plasmonics. The uniformity, thickness and homogeneity of the polymer shell will affect the properties of the system which makes a thorough structural characterization of these core-shell silver-polymer nanoparticles of great importance. However, visualizing the shell and the particle simultaneously is far from straightforward due to the sensitivity of the polymer shell towards the electron beam.

TiO₂ Films Modified with Au Nanoclusters as Self-Cleaning Surfaces under Visible Light.

In this study, we applied cluster beam deposition (CBD) as a new approach for fabricating efficient plasmon-based photocatalytic materials. Au nanoclusters (AuNCs) produced in the gas phase were deposited on TiO₂ P25-coated silicon wafers with coverage ranging from 2 to 8 atomic monolayer (ML) equivalents. Scanning Electron Microscopy (SEM) images of the AuNCs modified TiO₂ P25 films show that the surface is uniformly covered by the AuNCs that remain isolated at low coverage (2 ML, 4 ML) and aggregate at higher coverage (8 ML).

Plasmonic Near-Field Localization of Silver Core-Shell Nanoparticle Assemblies via Wet Chemistry Nanogap Engineering.

Silver nanoparticles are widely used in the field of plasmonics because of their unique optical properties. The wavelength-dependent surface plasmon resonance gives rise to a strongly enhanced electromagnetic field, especially at so-called hot spots located in the nanogap in-between metal nanoparticle assemblies. Therefore, the interparticle distance is a decisive factor in plasmonic applications, such as surface-enhanced Raman spectroscopy (SERS).

Harvesting Hydrogen Gas from Air Pollutants with an Unbiased Gas Phase Photoelectrochemical Cell.

The concept of an all-gas-phase photoelectrochemical (PEC) cell producing hydrogen gas from volatile organic contaminated gas and light is presented. Without applying any external bias, organic contaminants are degraded and hydrogen gas is produced in separate electrode compartments. The system works most efficiently with organic pollutants in inert carrier gas.

Biotemplated diatom silica-titania materials for air purification.

We present a novel manufacture route for silica-titania photocatalysts using the diatom microalga Pinnularia sp. Diatoms self-assemble into porous silica cell walls, called frustules, with periodic micro-, meso- and macroscale features. This unique hierarchical porous structure of the diatom frustule is used as a biotemplate to incorporate titania by a sol-gel methodology.

Concept and validation of a fully automated photocatalytic test setup.

Photocatalytic activity can be studied by several methods, each with its own strengths and weaknesses. To study photocatalytic activity in an easy, user-friendly, and realistic way, a completely new setup has been built. The setup is modularly constructed around Fourier transform infrared spectroscopy (FTIR) spectroscopy at the heart of it, resulting in great versatility.

A non-aqueous synthesis of TiO₂/SiO₂ composites in supercritical CO₂ for the photodegradation of pollutants.

Titania/silica composites with different Ti/Si ratios are synthesized via a nonconventional synthesis route. The synthesis involves non-aqueous reaction of metal alkoxides and formic acid at 75 °C in supercritical carbon dioxide. The as-prepared composite materials contain nanometer-sized anatase crystallites and amorphous silica.