High-performance photoelectrochemical aptasensor for enrofloxacin based on Bi-doped ultrathin polymeric carbon nitride nanocomposites with SPR effect and carbon vacancies

The development of photoactive materials with high photoelectrochemical (PEC) activity and stability is of great significance for PEC biosensors. In this work, the performance of carbon vacancies (CVs) in PEC biosensors was explored. A facile one-pot hydrothermal approach was used to prepare Bi-doped ultrathin polymeric carbon nitride (Bi/CV-PCN) nanocomposites with CVs, which displayed high PEC activity and stability. The surface plasmon resonance (SPR) effect of Bi boosted the visible light capture, and the intermediate energy levels induced by CVs generation enhanced charge separation efficiency, resulting in a remarkable improvement in PEC stability. Furthermore, the PEC signal of the Bi/CV-PCN was 24-fold, 6-fold and 2-fold higher than that of pristine Bi, graphitic carbon nitride and PCN, respectively. Based on its promising PEC properties, Bi/CV-PCN was utilized as the photoactive material for the sensitive and selective detection of enrofloxacin (ENR) in the concentration range of 1.0 x 10(-5)-1.0 x 10(3) ng.mL(-1), with a limit of detection of 3.3 x 10(-6) ng.mL(-1). This work could not only provide new insights for the development of materials with high PEC activity and stability, but also offer a simple and high-performance method to detect ENR.