Stable graphene@black phosphorus nanocomposites for photoelectrochemical aptasensing of bisphenol A

The synthesis processes of black phosphorus (BP) nanosheets are generally complicated and expensive. More seriously, these BP nanosheets suffer from poor stability at ambient conditions as well as low conductivities, hindering their photoelectrochemical (PEC) sensing applications. In this work, a facile and cost-effective solvothermal method is developed for the in-situ growth of BP nanosheets on the surface of graphene (Gr) nanosheets (Gr@BP), where a cheap, stable and industry-available red phosphorus is used as the precursor. Characterization results of different Gr@BP nanocomposites reveal the formation of C-P and C-O-P covalent bonds between the BP nanosheets and Gr nanosheets, resulting in significantly improved stability, electrical conductivity and PEC properties of the BP nanosheets. After functionalization of an amino-rich Gr@BP nanocomposite with aminated bisphenol A (BPA) aptamer with aid of glutaraldehyde as the cross-linker, a sensitive, selective and stable PEC aptasensor that is driven by visible light is assembled toward the monitoring of a typical environmental pollutant - BPA. This work provides a facile and cheap strategy to synthesize and explore novel PEC applications of different and stable BP nanomaterials.