An ultra-sensitive dopamine photoelectrochemical sensing platform based on two-dimensional Zn carbon nanosheets, hollow Cu2O and CdTe QDs composite films

Abstract

In this work, two-dimensional Zn carbon nanosheets (CNs) are obtained after heat treatment of in situ synthesized ZIF-8/NaCl nanocomposites, which are ultrasonically mixed with carboxylated multi-walled carbon nanotubes (MWCNTs). Subsequently, the nanocomposites Zn CNs-MWCNTs with large specific surface area and excellent catalytic properties are obtained. Meanwhile, the photoelectric material H–Cu2O/CdTe QDs are drop-coated on Zn CNs-MWCNTs/GCE and the modified electrode Zn CNs-MWCNTs/H–Cu2O/CdTe QDs/GCE is obtained. Eventually, a novel dopamine photoelectrochemical sensor based on Zn CNs-MWCNTs/H–Cu2O/CdTe QDs/GCE is constructed. Among them, the photocurrent intensity of H–Cu2O/CdTe QDs is much higher than that of pure H–Cu2O and pure CdTe QDs. This is due to the effective combination of CdTe QDs and H–Cu2O to form a p-p heterojunction, which can effectively suppress the recombination of electron-hole pairs. Subsequently, the working mechanism of the photoelectrochemical sensor is investigated in depth by the Kubelka-Munk model. At the same time, the photoelectrochemical sensor has reliable selectivity, stability, reproducibility and limit of detection (LOD = 0.3 nM), and also provides a new idea for the detection of dopamine.