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 & mu;M and 10-250 & mu;M, 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.