A highly sensitive photoelectrochemical sensor for 4-aminophenol based on CdS-graphene nanocomposites and molecularly imprinted polypyrrole

• Graphene (GR) remarkably promoted the photoelectrochemical activity of CdS QDs.
• MIP enhanced the photoelectrochemical response of CdS-GR to 4-aminophenol.
• A visible-light photoelectrochemical sensor for 4-aminophenol was constructed.
• MIP/CdS-GR photoelectrochemical sensor provided high sensitivity and selectivity.

A novel visible-light photoelectrochemical sensor was prepared based on FTO electrode modified with CdS quantum dots (QDs), graphene (GR) and molecularly imprinted polypyrrole (MIP). The electrochemical impedance spectra (EIS) indicated that GR facilitated the electron transfer of CdS modified electrode. Small amount of GR doped in CdS film could dramatically improve the photoelectrochemical response of modified electrode under visible-light illumination. While a MIP layer of 4-aminophenol was deposited on CdS-GR nanocomposites modified electrode, the photocurrent response to 4-aminophenol on the modified electrode was obviously promoted due to the specific binding of MIP with 4-aminophenol. The photoelectrochemical response was linearly proportional to the concentration of 4-aminophenol in the range of 5.0 × 10−8 mol L−1 to 3.5 × 10−6 mol L−1, with a detection limit (3S/N) of 2.3 × 10−8 mol L−1. Moreover, the MIP/CdS-GR modified FTO electrode showed excellent selectivity. The proposed visible-light photoelectrochemical sensor based on MIP/CdS-GR/FTO provided a feasible tool for rapid, sensitive and selective determination of 4-aminophenol.