Bi2WO6@g-C3N4 Heterostructure for Cathodic Photoelectrochemical Dopamine Sensor

A simple and low-cost cathodic photoelectrochemical (PEC) sensor based on Bi2WO6@g-C3N4 was designed for dopamine (DA) detection. The Bi2WO6 nanoflower was first prepared using a simple hydrothermal method followed by the combination with g-C3N4 nanosheet to form the Bi2WO6@g-C3N4 heterostructure. The heterostructure can extend the absorbance to the visible region and accelerate the transfer of charge carriers. Furthermore, DA easily coordinates with exposed Bi3+ on the Bi2WO6 surface and forms the charge-transfer complex to further enhance the cathodic photocurrent. Under optimal conditions, there are two linear relationships between the concentration of DA and photocurrent intensity. The linear ranges are 0.1–10 µM and 10–250 µM, with a sensitive detection limit (LOD) of 28 nM. Notably, the real sample of human blood serum analysis further revealed the accuracy and feasibility of the Bi2WO6@g-C3N4-based PEC platform. Convincingly, the heterostructure of Bi2WO6 and g-C3N4 opened up a new avenue for the construction of DA analysis.