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- Title
The effect of oxidative functionalization of carbon nanotubes on the morphological, optical, and photoelectrochemical properties of modified titanium dioxide photoanodes.
- Authors
Peón-Díaz, Francisco J.; del Río, Rodrigo Segura; Hevia, Samuel; Olivares, Fernanda; Expósito-Gálvez, Juan Carlos; Escalante, Renán; Valadez-Villalobos, Karen; Riquelme, Antonio J.; Oskam, Gerko; Henríquez, Ricardo
- Abstract
In this work, we demonstrate the influence of the oxidative treatment of carbon nanotubes (CNTs) on the morphological, optical, and photoelectrochemical properties of CNTs-TiO2 photoanodes. CNTs were synthesized by a chemical vapor deposition method (CVD) and subsequently oxidized in a mixture of HNO3/H2SO4 to introduce nitrogen- and oxygen-containing functional groups. The oxidation time was varied (45, 90, and 180 min) to obtain CNTs with different oxidation levels (CNTs-ox). Pristine and oxidized CNTs were deposited on ITO and used as substrates to fabricate ITO/CNTs/TiO2 photoelectrodes by depositing a TiO2 thin layer using a CVD procedure. The extent of oxidation of the CNTs was found to directly influence the homogeneity and morphology of the TiO2 overlayer, its physical stability, and the optical and photoelectrochemical properties of the photoelectrodes. An optimum oxidative treatment was achieved for 90 min, leading to a CNTs-ox/TiO2 electrode with the best performance. Compared to shorter and longer times, this sample showed the smallest bandgap and the best homogeneity of TiO2 growth on the CNTs' surface. Optimal photoelectrochemical performance was also found for this sample (160 μA/cm2 at 0 V vs. Ag/AgCl) in KCl (0.1 M) electrolyte (100 mW/cm2, Xenon arc lamp).
- Subjects
TITANIUM dioxide; CARBON nanotubes; CHEMICAL vapor deposition; ELECTRODE performance; FUNCTIONAL groups
- Publication
Journal of Materials Science, 2023, Vol 58, Issue 12, p5372
- ISSN
0022-2461
- Publication type
Article
- DOI
10.1007/s10853-023-08351-4