TiO<sub>2</sub>/LaFeO<sub>3</sub> Composites for the Efficient Degradation of Benzoic Acid and Hydrogen Production
LaFeO<sub>3</sub>/TiO<sub>2</sub> composites were prepared in the range 0–12.2 wt% of LaFeO<sub>3</sub>, characterized, and tested for both benzoic acid (BA) and 4-methoxycinnamic acid (MCA) degradation in aqueous solution, and hydrogen evolution. The preparation...
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| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-03-01
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| Series: | Molecules |
| Subjects: | |
| Online Access: | https://www.mdpi.com/1420-3049/30/7/1526 |
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| Summary: | LaFeO<sub>3</sub>/TiO<sub>2</sub> composites were prepared in the range 0–12.2 wt% of LaFeO<sub>3</sub>, characterized, and tested for both benzoic acid (BA) and 4-methoxycinnamic acid (MCA) degradation in aqueous solution, and hydrogen evolution. The preparation method was via ball-milling without thermal treatment. The composite materials presented agglomerates of LaFeO<sub>3</sub> with an average size from 1 to 5 μm, and the TiO<sub>2</sub> powder was well dispersed onto the surface of each sample. They showed varying activities for BA degradation depending on composition and light wavelength. The 6.2 wt% and 12.2 wt%-LaFeO<sub>3</sub>/TiO<sub>2</sub> composites exhibited the highest activity under 380–800 nm light and could degrade BA in 300 min at BA concentration 13.4 mg L<sup>−1</sup> and catalyst 0.12 g L<sup>−1</sup>. Using a 450 nm LED light source, all composites degraded less than 10% of BA, but in the presence of H<sub>2</sub>O<sub>2</sub> (1 mM) the photocatalytic activity was as high as 96% in <120 min, 6.2 wt%-LaFeO<sub>3</sub>/TiO<sub>2</sub> composite being the most efficient sample. It was found that in the presence of H<sub>2</sub>O<sub>2</sub>, BA degradation followed first order kinetic with a reaction rate constant of 4.8 × 10<sup>−4</sup> s<sup>−1</sup>. The hydrogen production rate followed a classical volcano-like behavior, with the highest reactivity (1600 μmol h<sup>−1</sup>g<sup>−1</sup> at 60 °C) in the presence of 3.86%wt- LaFeO<sub>3</sub>/TiO<sub>2</sub>. It was also found that LaFeO<sub>3</sub>/TiO<sub>2</sub> exhibited high stability in four recycled tests without losing activity for hydrogen production. Furthermore, a discussion on photogenerated charge-carrier transfer mechanism is briefly provided, focusing on lacking significant photocatalytic activity under 450 nm light, so p-n heterojunction formation is unlikely. |
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| ISSN: | 1420-3049 |