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Your search keyword '"Bignozzi, C.A."' showing total 3 results
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3 results on '"Bignozzi, C.A."'

1. Efficient Anodically Grown WO3 for Photoelectrochemical Water Splitting.

Author

Caramori, S., Cristino, V., Meda, L., Tacca, A., Argazzi, R., and Bignozzi, C.A.

Subjects
TUNGSTEN oxides, CRYSTAL growth, PHOTOELECTROCHEMISTRY, WATER, CHEMICAL reactions, SOLVENTS, POTENTIOSTAT, ELECTROLYTES, SIMULATION methods & models
Abstract

Abstract: The potentiostatic anodization of metallic tungsten has been investigated in different solvent/electrolyte compositions with the aim of improving the photoelectrochemical performances of the tungsten oxide layer. Among the explored electrolytes, the anodization in the NMF/H2O/NH4F solvent mixture was found to produce the most efficient WO3 photoanodes, which, combining spectral sensitivity, high electrochemically active surface and improved charge transfer kinetics, outperform, under simulated solar illumination, most of the reported nanocrystalline substrates produced by anodization in aqueous electrolytes and by sol gel methods. While the preparation of the photoelectrodes is a slow process at room temperature (20°C), it could be greatly accelerated (x 10) by carrying out the anodization at 40-50°C, thus proving to be a fast and convenient approach to the production of high performing WO3 photoactive substrates directly connected to a metal electron collector. [Copyright &y& Elsevier]

Published
2012
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2. Photoelectrocatalytic degradation of emerging contaminants at WO3/BiVO4 photoanodes in aqueous solution

Author

Carlo Alberto Bignozzi, Luca Pasquini, Federico Boscherini, Stefano Caramori, Alberto Piccioni, Francesco Passabi, Luisa Pasti, Nicola Marchetti, Jagadesh Kopula Kesavan, Lucia Amidani, Serena Berardi, Alessandra Molinari, Michele Orlandi, Vito Cristino, Nicola Bazzanella, Cristino V., Pasti L., Marchetti N., Berardi S., Bignozzi C.A., Molinari A., Passabi F., Caramori S., Amidani L., Orlandi M., Bazzanella N., Piccioni A., Kopula Kesavan J., Boscherini F., and Pasquini L.

Subjects
Materials science, heterojunction, genetic structures, water, photocatalytic degradation, fabrication, 02 engineering and technology, Electrolyte, x-ray absorption spectroscopy, film, 010402 general chemistry, Electrochemistry, Photochemistry, 01 natural sciences, bivo4, efficient, photocatalysi, Oxidizing agent, mineralization, Physical and Theoretical Chemistry, Visible-light, X-ray absorption spectroscopy, transformation, Aqueous solution, Ambientale, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Photocatalysis, Degradation (geology), 0210 nano-technology, Mesoporous material, Photoelectrocatalytic WO3/BiVO4
Abstract

WO3/BiVO4 films obtained by electrochemical deposition of BiVO4 over mesoporous WO3 were applied to the photoelectrochemical degradation of selected emerging contaminants (ketoprofen and levofloxacine) in aqueous solutions. The WO3/BiVO4 films in this work are characterized by a mesoporous morphology with a maximum photoconversion efficiency >40% extending beyond 500 nm in Na2SO4 electrolytes. Oxygen was found to be the dominant water oxidation product (ca. 90% faradaic yield) and no evidence for the photogeneration of OH radicals was obtained. Nevertheless, both 10 ppm levofloxacine and ketoprofen could be degraded at WO3/BiVO4 junctions upon a few hours of illumination under visible light. However, while levofloxacine degradation intermediates were progressively consumed by further oxidation at the WO3/BiVO4 interface, ketoprofen oxidation byproducts, being stable aromatic species, were found to be persistent in aqueous solution even after 15 hours of solar simulated illumination. This indicates that, due to the lower oxidizing power of photogenerated holes in BiVO4 and a different water oxidation mechanism, the employment of WO3/BiVO4 in photoelectrochemical environmental remediation processes is much less universal than that possible with wider band gap semiconductors such as TiO2 and WO3.

Published
2019

3. Modification of Nanocrystalline WO3 with a Dicationic Perylene Bisimide: Applications to Molecular Level Solar Water Splitting

Author

Maurizio Prato, Roberto Argazzi, Stefano Caramori, Zois Syrgiannis, Carlo Alberto Bignozzi, Vito Cristino, Federico Ronconi, Aurelio Bonasera, Ronconi, Federico, Syrgiannis, Zoi, Bonasera, Aurelio, Prato, Maurizio, Argazzi, Roberto, Caramori, Stefano, Cristino, Vito, Bignozzi, Carlo Alberto, Ronconi F., Syrgiannis Z., Bonasera A., Prato M., Argazzi R., Caramori S., Cristino V., and Bignozzi C.A.

Subjects
Models, Molecular, Molecular Conformation, Nanoparticle, Imides, Photochemistry, Biochemistry, Tungsten, Catalysis, NO, Catalysi, Electron Transport, chemistry.chemical_compound, Colloid and Surface Chemistry, TheoryofComputation_ANALYSISOFALGORITHMSANDPROBLEMCOMPLEXITY, WO3, ComputingMethodologies_SYMBOLICANDALGEBRAICMANIPULATION, perylene, Photoelectrochemical cell, IrO2, Quenching (fluorescence), Chemistry (all), charge transfer, Water, Oxides, General Chemistry, Photochemical Processes, Solar fuel, Nanocrystalline material, perylene, WO3, charge transfer, IrO2, Microsecond, chemistry, Water Splitting, Sunlight, VISIBLE-LIGHT, ARTIFICIAL PHOTOSYNTHESIS, PHOTOELECTROCHEMICAL CELL, OXIDATION CATALYSTS, ELECTRON-TRANSFER, FABRICATION, Nanoparticles, Perylene bisimide, Water splitting, Perylene, MathematicsofComputing_DISCRETEMATHEMATICS
Abstract

[(N,N?-Bis(2-(trimethylammonium)ethylene) perylene 3,4,9,10-tetracarboxylic acid bisimide)(PF6)2] (1) was observed to spontaneously adsorb on nanocrystalline WO3 surfaces via aggregation/hydrophobic forces. Under visible irradiation (? > 435 nm), the excited state of 1 underwent oxidative quenching by electron injection (kinj > 108 s-1) to WO3, leaving a strongly positive hole (Eox ? 1.7 V vs SCE), which allows to drive demanding photo-oxidation reactions in photoelectrochemical cells (PECs). The casting of IrO2 nanoparticles (NPs), acting as water oxidation catalysts (WOCs) on the sensitized electrodes, led to a 4-fold enhancement in photoanodic current, consistent with hole transfer from oxidized dye to IrO2 occurring on the microsecond time scale. Once the interaction of the sensitizer with suitable WOCs is optimized, 1/WO3 photoanodes may hold potentialities for the straightforward building of molecular level devices for solar fuel production.

Published
2015

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