https://doi.org/10.1140/epjs/s11734-025-01977-2
Regular Article
N+ ions implanted TiO2 nanotube arrays with enriched oxygen vacancies for photoreduction of nitrogen for ammonia synthesis
College of Physics and Materials Science, Tianjin Normal University, 300387, Tianjin, China
a
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Received:
15
July
2025
Accepted:
18
September
2025
Published online:
29
September
2025
Abstract
Photocatalytic nitrogen fixation for ammonia (NH3) production using TiO2 as photocatalysts is promising alternative to the traditional Haber–Bosch process due to its energy-saving and eco-friendly nature. However, some essential difficulties, including high recombination of photocarriers and inefficient light absorption, still make the simultaneous achievement of a high NH3 yield rate very difficult. To address this issue, we herein reported a nitrogen-doped TiO2 nanotubes (NTNTs) supported on Ti mesh synthesized by nitrogen ions implantation and subsequent anodization. The sample of NTNTs-5 possesses the best ammonia yield of 10.1 μmol L−1 h−1 cm−2cat under UV light irradiation and 5.49 μmol L−1 h−1 cm−2cat under visible light irradiation. By adding EDTA (h+ quencher) in water, the ammonia production significantly increases to 16.7 μmol L−1 h−1 cm−2cat under UV light irradiation, which is 6.63 times higher than that of unimplanted sample. VO of NTNTs were confirmed via the methods of Raman, XPS, ESR and H2O2 treatment. The doped nitrogen ions narrow the bandgap of the implanted samples and increase the separation of photocarriers. The structure of vertical nanotubes grown on the Ti mesh is favorable to absorbing both nitrogen and light. Therefore, the synergistic effect originated from implanted nitrogen ions, VO and vertical nanotube structure raises the efficiency of photocatalytic reduction of nitrogen to ammonia. The ammonia yield of NTNTs-5 still maintains at 10.1 μmol L−1 h−1 cm−2cat under UV light irradiation after five cycles, which means high stability of the implanted samples. This work comes up with a novel perspective to prepare photocatalysts with enriched VO by the method of ion implantation to boost photocatalytic reduction of nitrogen for ammonia production.
Supplementary Information The online version contains supplementary material available at https://doi.org/10.1140/epjs/s11734-025-01977-2.
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Springer Nature or its licensor (e.g. a society or other partner) holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
