Photoelectrochemical Behavior of Silver Nanoparticles inside Mesoporous Titania: Plasmon-Induced Charge Separation Effect

Couzon, Nelly; Maillard, Mathieu; Chassagneux, Fernand; Brioude, Arnaud; Bois, Laurence

doi:10.1021/acs.langmuir.8b03617

Cited by 13 publications

(11 citation statements)

References 45 publications

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“…However, there are also two major drawbacks that intrinsically impair the efficiency of pure TiO 2 -based photocatalysts: the first is a band gap of ≈3.0-3.2 eV which limits photon absorption to the UV spectrum and thus to the small fraction of ≈5% solar photon energy [2,40]; the second is relatively fast recombination rates of photogenerated electron-hole pairs due to their limited mobility and short lifetimes [2,41]. There are numerous approaches to address these two issues including metal and/or nonmetal-doping [40,42,43] (to partially replace either the Ti 4+ and/or O 2− sites), heterojunction formation [20,44], Z-schemes [45,46], decoration with quantum dots [47] and-with more recent success-hydrogenation towards "black" TiO 2 [48] or introduction of surface plasmon resonance (SPR) active noble metal nanoparticles (NPs) [41,[49][50][51][52][53]. To develop TiO 2 photocatalysts, it is, therefore, necessary to address both origins-structure and intrinsic optoelectrochemical properties.…”

Section: Introductionmentioning

confidence: 99%

Multi-Layered Mesoporous TiO2 Thin Films: Photoelectrodes with Improved Activity and Stability

2019

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This work aims at the identification of porous titanium dioxide thin film (photo)electrodes that represent suitable host structures for a subsequent electrodeposition of plasmonic nanoparticles. Sufficient UV absorption and electrical conductivity were assured by adjusting film thickness and TiO 2 crystallinity. Films with up to 10 layers were prepared by an evaporation-induced self-assembly (EISA) method and layer-by-layer deposition. Activities were tested towards the photoelectrochemical oxidation of water under UV illumination. Enhanced activities with each additional layer were observed and explained with increased amounts of immobilized TiO 2 and access to more active sites as a combined effect of increased surface area, better crystallinity and improved transport properties. Furthermore, films display good electrochemical and mechanical stability, which was related to the controlled intermediate thermal annealing steps, making these materials a promising candidate for future electrochemical depositions of plasmonic noble metal nanoparticles that has been further demonstrated by incorporation of gold.

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Section: Introductionmentioning

confidence: 99%

Multi-Layered Mesoporous TiO2 Thin Films: Photoelectrodes with Improved Activity and Stability

2019

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“…On the UV–visible spectrum, this is characterized by a large absorption peak at around 420–450 nm, which is related to the surface plasmon resonance of Ag NPs. This peak is red-shifted compared to the usual peak of silver NPs observed in materials and is attributed to two main factors: the high refractive index of titania (2.5) and the existence of an interfacial charge transfer. − …”

Section: Resultsmentioning

confidence: 85%

Electroactive Area from Porous Oxide Films Loaded with Silver Nanoparticles: Electrochemical and Electron Tomography Observations

Couzon

Roiban

Chassagneux

et al. 2019

ACS Appl. Mater. Interfaces

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Electrochemical studies of nanomaterial-based electrodes have been widely developed for catalyst and energy-harvesting applications. The evolution of these electrodes over time and their efficiency have been extensively studied and analyzed in order to optimize their performance. However, the electrochemical responses of electrodes are rarely studied in terms of the position of the active species within these electrodes. In this paper, we highlight that the spatial location of silver nanoparticles (NPs) embedded inside semiconductive porous films, TiO 2 or Fe 2 O 3 , is crucial for the electrochemical response. In fact, by using cycling voltammetry and electron tomography experiments, we show the existence of an "electroactive area", corresponding to a reduced thickness of the sample in close vicinity to a fluorine-doped tin oxide substrate where most of the electrochemical responses originate. Our results demonstrate that, for a film thickness of several hundred nanometers, only less than 30 nm close to the substrate responds electrochemically. However, cyclic voltammetry empties the electroactive area of silver NPs. Therefore, application of chronoamperometry coupled to irradiation allowed regeneration of this area thanks to an increased diffusion of silver species. In this paper, we also show the significant diffusion of silver species within the film during electrochemical experiments, a phenomenon even increased by irradiation. These results are therefore an important step that shows the importance of the localization of active species within a porous film and help in understanding and increasing the durability of nanomaterial-based electrodes.

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“…[ 125 ] As shown in Figure 6b, hot carrier generation within the plasmonic particle can overcome the interface Schottky barrier to be injected into the energy storage system. [ 126–128 ] With a catalyst layer that is more n‐type than the CSM, excess electrons which are not eliminated through redox transitions or recombination, can be swept into the catalyst layer through the heterojunction. Post‐illumination, discharging of the CSM can be transferred to the catalytic material, or to the surface where catalysis can also take place.…”

Section: Additional Strategiesmentioning

confidence: 99%

Post‐Illumination Photoconductivity Enables Extension of Photo‐Catalysis after Sunset

Loh

Sharma

Kherani

et al. 2021

Advanced Energy Materials

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Cloud‐cover‐induced frequent and sharp dips in sunlight as well as diminished solar flux during the evenings of peak energy demand are major challenges in solar energy harvesting. Persistent and memory‐based photocatalysts that efficiently operate under low light fluxes beyond sunset, are a potential solution to address and mitigate these challenges. This review describes examples of persistent photocatalysis systems based on charge injection into multivalent charge storage materials that allow post‐illumination discharging and charge carrier generation that increase or maintain the catalysis rate. Persistent photocatalysis in defect‐laden charge storage materials with multivalent states combined with slow charge release associated with electronic persistent photoconductivity results in giant persistent photocatalysis that can last more than an hour after the illumination is shut off. Strategies are suggested to develop persistent photocatalysis by improved charge separation and present figures of merit for evaluating persistent photocatalysis efficiency and performance. Furthermore, this could enable the use of such material systems in environmental applications such as photocatalytic coatings for the remediation of air pollution that continue to function into the night and self‐cleaning applications that continue to disinfect during the night.

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Photoelectrochemical Behavior of Silver Nanoparticles inside Mesoporous Titania: Plasmon-Induced Charge Separation Effect

Cited by 13 publications

References 45 publications

Multi-Layered Mesoporous TiO2 Thin Films: Photoelectrodes with Improved Activity and Stability

Multi-Layered Mesoporous TiO2 Thin Films: Photoelectrodes with Improved Activity and Stability

Electroactive Area from Porous Oxide Films Loaded with Silver Nanoparticles: Electrochemical and Electron Tomography Observations

Post‐Illumination Photoconductivity Enables Extension of Photo‐Catalysis after Sunset

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