Highly sensitive photoelectrochemical sensing of bisphenol A based on zinc phthalocyanine/TiO2 nanorod arrays.

A facile and sensitive photoelectrochemical (PEC) sensing platform based on zinc phthalocyanine (ZnPc) sensitized TiO2 nanorodarrays (NRAs) was successfully fabricated for detection of bisphenol A (BPA). The vertically aligned TiO2 NRAs with one-dimensional (1D) nanostructure was synthesized in-situ on fluorine-doped tin oxide-coated glass (FTO) substrate by simple one-step hydrothermal method, and then the TiO2 NRAs/FTO surface was covered with ZnPc. 1D nanostructure of TiO2 NRAs could provide not only more spaces for the load of ZnPc, but direct pathways to reduce the recombination of electron-hole pairs, improving the photocatalytic efficiency. The combination of ZnPc with TiO2 NRAs extended effectively the absorption of TiO2 to visible region and improved greatly the charge transfer ability of TiO2 NRAs. With the addition of BPA, BPA was oxidized by photogenerated holes during PEC reaction so that the photocurrent of the PEC sensing platform increased. BPA could be quantified by measuring the photocurrent change. The developed PEC sensor exhibited outstanding analytical performance with high sensitivity, excellent stability and good reproducibility. A wide linear work range from 0.047 to 52.1 μM was obtained with a low detection limit of 8.6 nM. Meanwhile, the sensor was also used to evaluate the level of BPA in plastic products and food.