Facile Vacuum Annealed Titanium Dioxide for Enhanced Visible
Light - Photoelectrochemical Applications
Pooja Raveendran Nair, Rene Fabián Cienfuegos Pelaes, Bindu Krishnan, Josué Amilcar Aguilar Martínez, David Avellaneda Avellaneda, Miguel Angel Gracia Pinilla, Sadasivan Shaji
UNIVERSIDAD AUTÓNOMA DE NUEVO LEÓN
Abstract:
The intentional introduction of structural imperfections in titanium dioxide, known as defect-induced titanium dioxide, creates opportunities to customize its electronic and optical characteristics. This, in turn, provides distinct possibilities for its use in photocatalysis, energy conversion, and advanced materials science [1]. The limited ability of TiO2 to absorb visible light often hampers its photoelectrochemical performance and other visible light active practical applications. To overcome this obstacle, pristine titania is subjected to structural and optoelectronic modifications through the simple method of vacuum annealing, at temperatures ranging from 500 to 800 degrees Celsius for 5 hours. The objective of this study is to boost light absorption and facilitate efficient charge separation in these materials by introducing defects and inducing phase transformations, thereby improving their photocurrent generation. A range of characterization techniques, including X-ray diffraction, Electron microscopy (Scanning and Transmission), X-ray photoelectron Spectroscopy, Raman spectroscopy, and UV-Visible spectroscopy, are utilized to analyze the structural and optical features of the modified nanomaterials. These temperature-induced defects play a pivotal role in enhancing the material's photoelectrochemical activity by creating additional active sites for charge transfer [2]. The evaluation of photoelectrochemical performance involves systematic investigations into the current-voltage characteristics and impedance spectra of the materials. This study demonstrates the facile vacuum annealing technique as a promising avenue for defect tuning in nanomaterials for efficient solar energy conversion.
[1] X. Chen, L. Liu, P. Y. Yu, and S. S. Mao, “Increasing solar absorption for photocatalysis with black hydrogenated titanium dioxide nanocrystals,” Science, vol. 331, no. 6018, pp. 746–750, Feb. 2011, doi: 10.1126/science.1200448.
[2] P. Raveendran Nair et al., “Black titanium dioxide nanocolloids by laser irradiation in liquids for visible light photo-catalytic/electrochemical applications,” Appl. Surf. Sci., vol. 623, p. 157096, Jun. 2023, doi: 10.1016/j.apsusc.2023.157096.
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