The new strategy modified W18O49 improves the performance of photocatalytic synthesis of ammonia

On May 11, 2022, the research group of Bi Yingpu, a researcher at the Lanzhou Institute of Chemical Physics of the Chinese Academy of Sciences, held a research group in Angew. Chem. Int. A new research paper was published at Ed., titled “Anchoring Black Phosphorus Quantum Dots on Fe-Doped W18O49 Nanowires for Efficient Photocatalytic Nitrogen Fixation.” Through the combination of W18O49 electronic structure regulation and surface modification, the research group significantly improved the performance of photocatalytic synthesis of ammonia.

Photocatalytic synthesis of ammonia, which uses sunlight to convert nitrogen and water directly into ammonia, is considered one of the ideal new ammonia synthesis technologies because of its advantages of clean reaction and no harmful by-products. However, most of the photocatalysts reported so far have key problems such as serious photogenerated charge compounding, weak nitrogen adsorption, and difficult dissociation of N-N triple bonds during nitrogen reduction, resulting in generally low photocatalytic ammonia synthesis efficiency. Therefore, rational design and preparation of efficient nitrogen reduction fixed photocatalysts still face great challenges.

Recently, the research group of Researcher Bi Yingpu of Lanzhou Institute of Chemical Physics of the Chinese Academy of Sciences used the strategy of combining Fe element phase doping and surface anchored black phosphorus quantum dots (BPQDs) to modify the W18O49 nanowires, which realized the effective regulation of the electronic structure of W18O49 and the enhancement of surface nitrogen adsorption/activation performance, thereby significantly improving the catalytic activity of W18O49 fixed nitrogen gas synthesis of ammonia.

The relevant experimental characterization and theoretical calculation results show that the introduction of Fe dopant in the W18O49 phase can effectively reduce its work function and improve the center of the defect band, which has a higher nitrogen reduction potential and a lower photogenerated electron hole complex rate. In addition, surface anchoring BPQDs can not only significantly improve the N2 adsorption capacity of W18O49, but also facilitate the N-N triple bond fracture in the W-P dimer adsorption mode, thus effectively improving the chemical adsorption and desociation activity of nitrogen on the catalyst surface.

Compared with W18O49 nanowires, the photocatalytic ammonia synthesis performance of P-Fe/W18O49 was improved by nearly an order of magnitude after the synergistic modification of body phase Fe doping and surface BPQDs anchoring. This work provides new research ideas for the design and construction of efficient photocatalysts for the synthesis of ammonia under mild conditions.

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