Enhanced photocatalytic nitrogen fixation performance via in situ constructing BiO2–x/NaNbO3 heterojunction

The fabrication of heterojunction catalysts is an effective strategy to enhance charge separation efficiency, thereby boosting the performance of photocatalysts. In this study, BiO2–x nanosheets were synthesized through a hydrothermal process and loaded onto NaNbO3 microcube to construct a series of BiO2–x/NaNbO3 heterojunctions for photocatalytic N2 fixation. Results indicated that 2.5% BiO2–x/NaNbO3 had the highest photocatalytic performance. The NH3 production rate under simulated solar light reached 406.4 μmol·L−1·g−1·h−1, which reaches 2.6 and 3.8 times that of NaNbO3 and BiO2–x, respectively. BiO2–x nanosheets primarily act as electron trappers to enhance the separation efficiency of charge carriers. The strong interaction between BiO2–x and NaNbO3 facilitate the electron migration between them. Meanwhile, the abundant oxygen vacancies in BiO2–x nanosheets may facilitate the adsorption and activation of N2, which may be another possible reason of the high photocatalytic activity of the BiO2–x/NaNbO3. This study may offer new insights for the development of semiconductor materials in photocatalytic nitrogen fixation.