In-situ construction of 1D β-FeOOH nanobelts/2D porous g-C3N4 heterojunction for enhanced “signal-on” photoelectrochemical aptasensing

Bisphenol A (BPA), a prevalent organic pollutant found in wastewater environment, is notorious for its resistance to natural degradation, raising significant ecological and human health concerns. In this study, a “signal-on” photoelectrochemical aptasensing system was designed for detecting BPA in real water samples with high specificity and sensitivity. One-dimensional (1D) β-FeOOH nanobelts were synthesized on a two-dimensional (2D) porous carbon nitride (g-C3N4) through an in-situ growth procedure. The β-FeOOH/g-C3N4 nanocomposites demonstrated superior photoelectric conversion efficiency due to several factors: (i) The 1D nanobelt-like structure of β-FeOOH shortens the charge transfer path within the nanocomposite, enabling directional and rapid migration of photoinduced charges from the interior to the surface. (ii) β-FeOOH possesses strong visible absorption capabilities, enhancing the utilization of g-C3N4 under photoexcitation, resulting in the generation of numerous photo-induced carriers. (iii) The in-situ formation of the β-FeOOH/g-C3N4 heterojunction establishes an intimate interfacial contact, facilitating the rapid separation and transfer of charges between β-FeOOH and g-C3N4. A photoelectrochemical aptasensing platform based on the photoactive material of β-FeOOH/g-C3N4 detects BPA with reduced photocurrent owing to the presence of BPA-aptamer macromolecules on the electrode surface. This BPA detection system exhibits excellent linearity over a wide concentration range from 10 pM to 10nM, with high sensitivity (a detection limit of 3.5 pM), stability, specificity, and repeatability. Furthermore, this research offers a straightforward and rapid sensing platform for monitoring BPA enriched water environments.