Study of the K2Ti6-xZrxO13 (x = 0 - 1) solid solution for enhancing the photocatalytic hydrogen production: Oxygen vacancies playing an important role in the catalytic performance

• Published in: Journal of photochemistry and photobiology. A, Chemistry. Vol. 409; p. 113134
• Main Authors: Ibarra-Rodriguez, Luz I., Huerta-Flores, Ali M., Garay-Rodríguez, Luis F., Torres-Martínez, Leticia M.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15-03-2021
• Subjects: Hydrogen evolution; Oxygen vacancies; Solid solution; Tunnel hexatitanate; Tunnel hexatitanate; Oxygen vacancies; Solid solution; Hydrogen evolution
• ISSN: 1010-6030; 1873-2666
• DOI: 10.1016/j.jphotochem.2021.113134

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•K2Ti1-xZrxO13 (x = 0–1) solid solution was prepared by the solid state method.•The crystal lattice distortion confirms the Ti4+ substitution by Zr4+ ions.•Zr4+ ions restricted the grain growth in the solid solution.•Zr4+ ions inside the tunnel structure promoted the creation of oxygen vacancies.•The excess of oxygen vacancies in the K2ZrTi5O13 solid solution promoted the H2 evolution.
The K2Ti6-xZrxO13 (x = 0–1) solid solution was prepared by the traditional solid-state synthesis method. The X-Ray diffraction patterns presented a proportional increase in the cell volume and crystal lattice distortion according to the increment of the Zr4+ species concentration in the reactant mixture. The morphological characterization showed a decrease in particle size average as a result of the zirconium presence due to crystal distortion. The photocatalytic performance was evaluated in the hydrogen evolution reaction in the presence of methanol. In this context, the K2Ti5ZrO13 solid solution exhibited the highest performance (72 μmolg−1 h−1) due to the higher presence of defects such as oxygen vacancies because of the Zr incorporation into the crystalline structure. In this context, these anionic defects can act as electron traps in bulk material and reduce recombination of charges; meanwhile, oxygen vacancies in surface create reactive Ti3+ ions, where the reactions of interest take place.