Photocatalytic TiO₂ Macroscopic Fibers Obtained Through Integrative Chemistry

Abstract

The photocatalytic properties of titanium dioxide depend not only on its electronic properties, but also on the material size and shape, which can increase interactions between the reactants and catalyst. Most studies to date show that reducing the particle size down to the nanoscale increases photocatalytic efficiency, as a result of a higher surface to volume ratio and because a larger proportion of the material is actually irradiated by light. We demonstrate that a multiscale shape design, which integrates surface roughness, particle shape, and 1D material processing and orientation, can favor photocatalytic properties in the solid–gas regime, especially mineralization (conversion into CO2), when the hierarchical 1D orientation of the material is combined with unidirectional gas flow. Several materials with hierarchical structure were prepared and characterized. They have been tested for the photocatalytic mineralization of gaseous acetone and compared with commercial catalysts. Our study reveals that a suitable combination of multiscale design and optimization of the material orientation and gas flow favors high mineralization.

TiO2 Macroscopic Fibers with Enhanced Photocatalytic Properties Obtained through a Scale‐Up Semi‐Industrial Process

“…Overall, the fibers present a flattened shape with a width ranging from 40 to 47 μm and a thickness ranging from 10 to 17 μm. Compared to those obtained when using a rotating beaker as coagulation medium (1.0 processed fibers, 100–200 μm), their diameter are much smaller and their morphology clearly different (Supporting Information Figure S3) . Indeed, for both types of fibers, the topology looked like a “tree trunk” at the macroscopic scale meaning that the fibers present large and deep striation at the surface oriented along the fibers main axis.…”

“…The nanoparticles were synthesized accordingly to the process described in our previous work . Typically, 5 mL of an HCl solution was first added to a 50 mL nonylphenol‐EO10 nonionic surfactant (Tergitol NP‐10) 15 wt% solution.…”

“…By contrast, conventional wet spinning can be scaled up and is actually already used for the industrial production of several synthetic fibers. This approach based on the injection and coagulation of fiber material dispersed in a liquid has already been employed in our group for the generation of macroscopic carbon nanotube fibers for actuators, titania fibers for photocatalysis, vanadium oxide for gas sensors, and zinc oxide fibers dedicated to photonics . In the case of vanadium oxide fibers, it was demonstrated that: (i) the inclusion of latex particles influences the PVA chains alignment, (ii) the alignment of the PVA chains and the nano‐ribbons along the fiber main axis has an impact on the fiber mesoscopic organization, and (iii) the mesoscopic organization modifies the detection of alcohol vapor.…”

“…We report in this study how the photocatalytic properties of titania fibers prepared previously by wet spinning, are improved by optimizing the fiber morphology for a better interaction with gas. This study provides the rational for future improvement of photocatalytic fibers, and demonstrates how mass transport, topology, and roughness must be taken into account in addition to the crystallinity and crystal phase.…”

Photoelectric conversion performances of Mn doped TiO2 under >420nm visible light irradiation

“…5c focuses on the O 1s binding energy at 529.7 eV (lattice TiO 2 oxygen atoms) with a shoulder centered at 531.5 eV. This latter feature is due to the presence of OH surface groups and possibly adsorbed water [35]. As we mentioned above, the samples have a quite low content of oxygen vacancy, which corresponds to the higher oxidation state of manganese [36,37].…”