ZnS Nanosphere Arrays/Graphene Foam for Voltammetric Sensing of Dopamine in the Presence of Uric Acid

Graphene foam (GF) was prepared by chemical vapor deposition (CVD) using nickel foam (NF) as sacrificial template. Afterward, ZnS nanosphere arrays (ZnS NSAs) were grown in situ on GF by hydrothermal synthesis. The ZnS NSAs/GF was used as sensing electrode to detect dopamine (DA) in the presence of uric acid (UA). The results show that ZnS NSAs with the diameter of ~500 nm are uniformly distributed on the three-dimensional GF. Ultrasensitive voltammetric response of the ZnS NSAs/GF electrode to DA, such as high sensitivity of 2.99 $\mu \text {A}\cdot \mu \text {M}^{-\textsf {1}} \cdot \text {cm}^{-\textsf {2}}$ and low limit of detection (LOD) of 0.04 $\mu \text{M}$ (at S/N = 3). In addition, it also shows good reproducibility and long-term stability, which is expected to be applied to the detection of DA in clinical practice.