Tremella-like ZnIn2S4/graphene composite based photoelectrochemical sensor for sensitive detection of dopamine.

Tremella-like ZnIn2S4 (ZISt) and flower-like microsphere ZnIn2S4 (ZISm) were synthesized via a straightforward hydrothermal method. It was found that the ZISt was superior to ZISm for photoelectrochemical (PEC) sensing because of its large surface area and high photocatalytic activity. A composite of ZISt and graphene (GR) was prepared and used for the PEC sensing of dopamine (DA). Here DA acted as an electron donor to scavenge the hole and inhibit the charge recombination. The GR enhanced visible light absorption and accelerated electron transfer, amplifying the photocurrent signal. The strong chelating coordination interaction between DA and Zn(II) in ZISt guaranteed the selective adsorption of target analyte. Thus the resulting ZISt/GR photoelectrode showed sensitive and selective PEC response to DA. Under the optimized conditions, the linear response range was from 0.01 to 20 μM, and the detection limit was down to 0.001 μM. Additionally, the sensor had good stability and reproducibility, and it could be used for the detection of DA in real samples.