Cathodic photoelectrochemical detection of PCB101 in environmental samples with high sensitivity and selectivity

A novel cathodic photoelectrochemical (PEC) sensing method was developed for fast and convenient detection of PCB101 taking advantages of the excellent PEC reducibility of Pd quantum dots (QDs) modified molecularly imprinted TiO₂ nanorods (NRs). Attributed to the efficient PEC reduction of PCB101 on the cathode surface, sensitive cathodic photocurrent would be produced with increasing PCB101 concentration under a negative bias potential, giving a low PCB101 detection limit of 5×10^-14molL^-1. Meanwhile, molecular imprinting (MI) technique was integrated by in situ introduction of MI sites on the surface of TiO₂ NRs, so that highly specific adsorption and reduction of PCB101 congener could be obtained. The results indicated that the PEC sensor presented excellent selectivity toward PCB101 with the coexistance of 100-fold excess of other pollutants including the PCBs congeners, other aromatic pollutants, and heavy metal ions. The cathodic PEC sensor was sucessfully applied in determination of PCB101 in real water and soil samples, and the results had good consistency with that obtained by the traditional GC-MS. This work provides a new concept and research basis for fabricating cathodic PEC sensor for the environmental pollutants with specific structures that were easily reduced.