Ternary heterojunctions composed of BiOCl, BiVO4 and nitrogen-doped carbon quantum dots for use in photoelectrochemical sensing: effective charge separation and application to ultrasensitive sensing of dopamine

Abstract

The use of ternary heterojunctions can lead to superior performance in photoelectrochemical (PEC) sensing. This can be ascribed to effective separation and reduced recombination probability of photogenerated electron-hole pairs. The authors describe the rational design of ternary heterojunctions comoposed of BiOCl, BiVO4 and nitrogen-doped carbon quantum dots (N-CDs). They exhibit enhanced photocurrent compared to the use of BiOCl/BiVO4, BiOCl, or BiVO4. The new material was used in a sensor platform for detection of the neurotransmitter dopamine (DA). Under zero voltage and visible light excitation, DA can be detected in the 1 pM to 10 μM concentration range, with a 0.3 pM lower detection limit (at an S/N ratio of 3). The sensor has rapid response and was applied to the determination of DA in spiked serum samples. Notably, this work also may assist in a better understanding of the relationship between kind of ternary heterojunctions and PEC performance. Conceivably, it can be extended to other PEC sensor platform and other photocatalytic system associated with photoactive materials.