Phase-Dependent Photocatalytic Activity of Nb<sub>2</sub>O<sub>5</sub> Nanomaterials for Rhodamine B Degradation: The Role of Surface Chemistry and Crystal Structure
Niobium oxides are promising materials for catalytic applications due to their unique structural versatility and surface chemistry. Nb<sub>2</sub>O<sub>5</sub> nanomaterials were synthesized via a solvothermal method at 150 °C using niobium oxalate as a precursor. A comprehen...
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| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-06-01
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| Series: | Nanomaterials |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2079-4991/15/11/846 |
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| Summary: | Niobium oxides are promising materials for catalytic applications due to their unique structural versatility and surface chemistry. Nb<sub>2</sub>O<sub>5</sub> nanomaterials were synthesized via a solvothermal method at 150 °C using niobium oxalate as a precursor. A comprehensive characterization of the material was performed using electron microscopy, X-ray diffraction, and Raman spectroscopy. The as-prepared nanoparticles primarily crystallized in a mixture of the TT-Nb<sub>2</sub>O<sub>5</sub> phase (TT from the German Tief-Tief, meaning “low-low”) and niobic acid, while subsequent thermal treatment at 900 and 1100 °C induced a phase transformation to T-Nb<sub>2</sub>O<sub>5</sub> and H-Nb<sub>2</sub>O<sub>5</sub>, respectively (T from the German Tief, meaning “low”, and H from Hoch, meaning “high”). The as-prepared samples consist of micro-coils composed of interconnected nanometer-scale fibers, whereas the morphology changes into rods when they are treated at 1100 °C. The photocatalytic performance of the nanoparticles was evaluated by comparing the as-prepared and thermally treated samples. The as-prepared nanoparticles exhibited the highest photocatalytic activity under visible illumination, achieving 100% degradation after 180 min. More interestingly, the treatment of the as-prepared material with H<sub>2</sub>O<sub>2</sub> modified the surface species formed on the Nb<sub>2</sub>O<sub>5</sub>, altering the photocatalytic behavior under various illumination conditions. This sample showed the highest photocatalytic activity under UV illumination, reaching 100% degradation after 75 min. On the other hand, the calcined samples are practically inactive, attributed to the loss of active catalytic sites during thermal treatment and phase transformation. |
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| ISSN: | 2079-4991 |