光诱导表面氧空位Bi4O5Br2的光催化固氮性能提升研究OA

Photocatalytic nitrogen fixation is a promising approach for artificial nitrogen fixation.Effective diffusion of nitrogen molecules to the active sites on photocatalysts is a prerequisite for subsequent chemical adsorption of N2.The main challenges in photocatalytic nitrogen fixation lie in the binding of N2 to catalysts,as well as the activation of the strong N≡N bond.Selecting suitable active sites is an effective strategy to enhance ammonia production efficiency.During the preparation of Bi4O5Br2,oxygen vacancy defects were successfully introduced in situ by photoinduction,resulting in oxygen-vacancy-rich Bi4O5Br2(OVs-Bi4O5Br2).The prepared photocatalyst OVs-Bi4O5Br2 was characterized using XRD,EPR,XPS,and SEM techniques.Its photocatalytic nitrogen fixation performance was evaluated,and its optical properties were analyzed.Experimental results show that compared with pristine Bi4O5Br2,OVs-Bi4O5Br2 exhibits significantly enhanced photocatalytic nitrogen fixation activity,with ammonia yield increasing approximately sevenfold under full-spectrum light irradiation,reaching 175.803 μmol/(h·g).The introduced oxygen vacancies not only narrow the band gap of Bi4O5Br2 but also make the conduction band potential more negative,thereby enhancing electron reduction capability.The effective separation of photogenerated carriers by oxygen vacancies is the primary reason for the improved photocatalytic nitrogen fixation activity.