Atomically Thin Bi2MoO6 Nanosheets for Efficient Visible-Light Photocatalytic Nitrogen Fixation via O-Vacancy Tailored Exposure of Mo Sites

Abstract

Efficient charge transfer and exposure of reactive sites represent critical factors in the enhancement of photocatalytic nitrogen fixation. Herein, an atomic-thickness phosphate-doped Bi₂MoO₆ photocatalyst was fabricated successfully. The introduction of PO₄^3– doping induced lattice distortions within the Mo–O octahedron, resulting in the generation of oxygen vacancies and exposure of Mo sites that served as active centers for nitrogen activation. Additionally, the incorporation of PO₄^3– dopants led to a reduced surface work function of Bi₂MoO₆, thereby effectively facilitating carrier migration. Furthermore, there is a notable reduction in carrier transport distance from the bulk to its surface due to the atomic sheet structure. As a consequence, the PO₄^3–-doped Bi₂MoO₆ exhibited a significantly enhanced photocatalytic nitrogen fixation activity compared to the undoped sample. Moreover, PO₄^3–-doped Bi₂MoO₆ showed improved photocatalytic performance for the reduction of Cr(VI). This work offers valuable theoretical insights for the development of highly efficient photocatalysts.