Co9S8-electrochemically reduced graphene oxide nanocomposites: A powerful electrochemical sensing platform for DA

In this study, a preparation of hollow nanoscale tubular polysulfide Co₉S₈ is reported, along with its use in building an electrochemical sensor that can detect dopamine (DA). Utilizing electrochemically reduced graphene oxide (ErGO) as a substrate, the Co₉S₈-ErGO/GCE sensor was made by attaching Co₉S₈ nanotubes to a glassy carbon electrode (GCE) surface. The use of ErGO in the sensor fabrication process not only improves the conductivity but also effectively prevents the aggregation of Co₉S₈. A large number of hollow Co₉S₈ nanotubes are anchored on ErGO, providing more catalytic active sites for electrode reactions. The constructed sensor shows remarkable DA detection ability, with a notable rise in peak current, thanks to the synergistic action of Co₉S₈ and ErGO. This sensor has a lower detection limit of 4.0 nM and a wide linear range of 0.01–0.1 µM, 0.1–2.0 µM, and 2.0–10 µM. It is also possible to quantify DA in actual samples using Co₉S₈-ErGO/GCE, meeting clinical requirements for reproducibility, selectivity and accuracy.