A photoelectrochemical sensor based on β-cyclodextrin-modified MoS2 quantum dots-WS2 nanosheet composites for the detection of benzo [a]pyrene

A photoelectrochemical sensor has been developed for the detection of the polycyclic aromatic hydrocarbon pollutant benzo [a]pyrene (BaP). An n -butyl lithium intercalation stripping method is applied to prepare tungsten disulphide nanosheets (WS 2 NSs). WS 2 NSs and β-cyclodextrin (β-CD)-modified MoS 2 quantum dots (QDs) are then compounded by hydrogen bonding between the amino and hydroxyl groups. After assembly on an indium tin oxide electrode, the energy level matching and synergistic photoelectric effect between β-CD-MoS 2 QDs and WS 2 NSs reduced the combination of photogenerated electrons and holes and an enhanced photocurrent signal is observed. As a result of the host–guest interaction between β-CD and BaP, BaP could bind to the β-CD-MoS 2 QDs in the nanocomposites, which hinders the electron migration to the electrode and weakened the photocurrent signal. Thus, the trace detection of BaP is realized. The rate of photocurrent change is also related to the BaP concentration from 1 to 20 nmol/L with a detection limit of 0.33 nmol/L. In summary, a highly sensitive and selective photoelectrochemical sensor for the detection of BaP is successfully constructed.