Search results for "visible light"
showing 10 items of 28 documents
Influence of laminated architectures of heterostructured CeO2-ZnO and Fe2O3-ZnO films on photodegradation performances
2020
Abstract The development of photocatalytically active films has gained a great attention in recent years. Herein, new heterostructured films associating ZnO and CeO2 or Fe2O3 and exhibiting various architectures were prepared by the solution precursor thermal spray (SPPS) process. The paper examines the effect of the films laminated architectures on the photodegradation performance. For CeO2-ZnO and Fe2O3-ZnO films, the photodegradation efficiency of the Orange II dye is 100% and 95% after 240 min UV light irradiation and after 360 min visible light irradiation, respectively. The photocatalytic activity of the laminated structures was found to depend on the materials used to construct the h…
Preparation of N-doped TiO2: characterization and photocatalytic performance under UV and visibile light
2009
Nanocrystalline N-doped TiO(2) samples were prepared by using TiCl(4) or TiOSO(4) as precursors. The powders were characterized by X-ray diffraction, BET specific surface area measurements, scanning electron microscopy, diffuse reflectance spectroscopy, Raman spectroscopy and X-ray photoelectron spectroscopy. The photocatalytic activity was tested using the photodegradation of 4-nitrophenol under UV and visible light.Some samples were more active than commercial Degussa P25. A shift of the absorption edge to a lower energy and a stronger absorption in the visible light region were observed in the samples obtained from TiCl(4). Two absorption edges were observed in the samples derived from T…
Visible Light Photocatalysis by a Titania-Rhodium (III) Complex
2009
Effect of quantized conductivity on the anomalous photon emission radiated from atomic-size point contacts
2019
We observe anomalous visible to near-infrared electromagnetic radiation emitted from electrically driven atomic-size point contacts. We show that the number of photons released strongly depends on the quantized conductance steps of the contact. Counter-intuitively, the light intensity features an exponential decay dependence with the injected electrical power. We propose an analytical model for the light emission considering an out-of-equilibrium electron distribution. We treat photon emission as bremsstrahlung process resulting from hot electrons colliding with the metal boundary and a find qualitative accord with the experimental data.
Efficient H2 production by photocatalytic water splitting under visible light over modified TiO2-based catalysts
2018
Efficient H2 production by photocatalytic water splitting under visible light over modified TiO2-based catalysts
Electrochemical fabrication of Cu2O/TiO2 nanotubes junctions with visible light photoactivity
2013
Visible Light Induced Oxidation of Ferulic Acid by TiO2 Photocatalysis
2012
Oxidation of ferulic acid (C10H10O4) in aqueous medium occurs by using both commercial and home prepared TiO2 samples under visible light irradiation. Among the oxidation products vanillin was found with a selectivity ranging from 1 to 2% with respect to the converted substrate. By considering that TiO2 is unable to absorb visible light and ferulic acid does not react in the absence of TiO2, the observed photoactivity may be explained by the formation of a charge-transfer complex between ferulic acid and TiO2, being the complex able to absorb visible light. Among all the tested semiconductor oxides, only Merck anatase TiO2 does not perform the oxidation of ferulic acid under visible light i…
Self-cleaning materials active in the visible range based on porphyrin-sensitised titanium dioxide
2016
In the last decades, nanostructured semiconductors played a central role in the material science scene because of their numerous applications spanning from renewable energy to organic/hybrid electronics up to photocatalysis. Titanium dioxide is one of the most used semiconductors because of its low cost, chemical stability, sustainability and versatility. Indeed, it is widely employed as photo-active or charge- transporting material in electronic devices, as photocatalyst in water de-pollution treatments etc.. Remarkably, one of the most interesting application of titanium dioxide consists of the protection and conservation of cultural heritages. Actually, TiO2 photocatalytic properties are…
Investigation of data encryption impact on broadcasting visible light communications
2014
Este trabajo investiga el impacto de la encriptación y desencriptación de datos en un sistema de comunicaciones de luz visible (VLC) de difusión en interiores incrustado en la capa física. Se ha implementado el cifrado RSA para proporcionar una transmisión de datos segura en la capa física. El artículo muestra el rendimiento de la tasa de error de bits (BER) para los sistemas VLC seguros y no seguros (8 y 12 bits) para velocidades de datos de 2 y 12 Mbps. Para una BER de 10e-4 mostramos que hay penalizaciones de potencia de 2-4 dB con las VLC seguras. También se investiga el impacto de la longitud de la clave en la propagación del error y la penalización de potencia. EU Cost Action IC1101 T…
Hybrid VLC/WiFi Architectures with Priority Feedback Channels
2022
In this paper, we consider integrating Visible Light Communication (VLC) and WiFi technologies in an ultra-dense (massive) Internet of Things scenario, where WiFi links are used for complementing VLC links and vice-versa. Indeed, in case of mobility and/or bidirectional communications, limited coverage areas and self-generated interference can be an issue. We consider hybrid VLC/WiFi nodes where the VLC link is used for the majority of (data) traffic and the WiFi link is employed as a feedback channel (e.g. transmitting TCP ACKs). In presence of intense WiFi traffic, the WiFi network may be congested and thus, to fully exploit the VLC bandwidth, we discuss possible priority mechanisms to fu…