Oxygen vacancy enhanced photoelectrochemical performance of Bi2MoO6/B, N co-doped graphene for fabricating lincomycin aptasensor

Oxygen defect-engineered is an important strategy to improve the photoelectric activity of materials. Herein, a facile one-pot solvothermal method was utilized to synthesize visible light-responsive photoactive Bi₂MoO₆ nanoparticles anchored boron and nitrogen co-doped graphene (BNG) nanosheets nanocomposites with oxygen vacancy. The incorporation of BNG nanosheets increased the oxygen vacancies amounts on Bi₂MoO₆ remarkably, and the presences of oxygen vacancies can be beneficial to broaden the absorption range. The absorption edge of Bi₂MoO₆/BNG was widened from 500 nm to 550 nm compared to Bi₂MoO₆, and the charge transfer was accelerated to improve the photoactive of Bi₂MoO₆/BNG. Under visible light illumination, the photoelectrochemical (PEC) response of the as-prepared Bi₂MoO₆/BNG was 11.6-fold, 6.7-fold, 3.1-fold and 2.4-fold higher than that of pristine Bi₂MoO₆, Bi₂MoO₆/graphene, Bi₂MoO₆/nitrogen doped graphene and Bi₂MoO₆/boron doped graphene. Using Bi₂MoO₆/BNG nanocomposites with the superior PEC performance as photoactive materials in combination with specifically recognized lincomycin (LIN) aptamer, a highly efficient PEC aptasensor was successfully constructed for sensitive analysis of LIN. Under optimal conditions, the proposed PEC aptasensor exhibited excellent analytical performance for LIN with a wide linear response of 1 × 10^-11 to 1 × 10^-6 mol L^-1 along with a low detection limit of 3.7 × 10^-12 mol L^-1 (defined as S/N = 3). The as-prepared Bi₂MoO₆/BNG nanocomposites exhibit excellent visible light response and PEC performance, indicating its potential applications in PEC biosensor.