Construction of an La-BiVO₄/O-Doped g-C₃N₄ Heterojunction Photocatalyst Embedded in Electrospinning Nanofibers

BiVO₄ has been widely used in the field of photocatalysis due to its nontoxic and moderate band gap. However, single BiVO₄ has the disadvantages of a high recombination rate of photogenerated carriers and weak response to visible light, inhibiting its photocatalytic applications. To explore viable solutions, a hybrid material composed of lanthanum-doped bismuth vanadate (La-BiVO₄) and oxygen-doped porous graphite carbon nitride (O-doped g-C₃N₄), i.e., La-BiVO₄/O-doped g-C₃N₄ powder, was prepared by a facile hydrothermal reaction and low-temperature calcination. Then, the powder was loaded on polyacrylonitrile nanofibers (NFs) through the electrospinning fiber technique. Various surface science characterizations, including transmission electron microscopy and nitrogen absorption and desorption analysis, confirmed the successful synthesis of a mesoporous heterojunction material. The La³⁺-doping as well as the porous morphologies and larger specific surface area of the O-doped g-C₃N₄ ultimately improve the photocatalytic abilities via a proposed Z-scheme heterojunction mechanism. The roles of La³⁺-doping and morphology modification in promoting the separation of the photogenerated carriers and broadening the optical absorption range were experimentally discussed. The RhB degradation experiment indicated that the La-BiVO₄/O-doped g-C₃N₄ powder has excellent photocatalytic activity, which is about 2.85 and 2 times higher than that of the pure BiVO₄ and O-doped g-C₃N₄, respectively. Meanwhile, the La-BiVO₄/O-doped g-C₃N₄ NF shows good stability and recoverability after a 10-cycle testing. Such a hybrid photocatalyst with a proposed Z-scheme heterojunction mechanism and good plasticity might pave a feasible way to fabricate a new library of photocatalysts.