A self-powered PFC sensing platform via integrating aptamer-modified photoanode and Z-scheme signal amplifying...

Microcystin-LR (MC-LR) is a hepatotoxin produced by cyanobacteria, which is biologically toxic, prevalent, and has serious effects on human health. Therefore, it is urgent to develop miniaturized and cost-efficient methods for MC-LR monitoring. Photocatalytic fuel cell (PFC) sensing has already been tipped as a promising approach for facile, on-site detection in environmental mediators. However, there are some tricky issues that have to be solved, such as low light utilization, poor charge separation, high manufacturing cost, and so on.

A self-powered aptasensor was fabricated for MC-LR detection based on the PFC system that integrates In₂O₃-CaIn₂S₄/ITO (IO-CIS/ITO) photoanode and CuBi₂O₄-PbS/ITO (CBO-PS/ITO) photocathode. The specific hollow tubular structure, excellent photoelectric properties, and stepped band structure of the IO-CIS photoanode assured a higher output power to a certain extent. Moreover, the unique Z-scheme heterojunction of the CBO-PS photocathode accelerated interfacial charge transfer and further amplified the output signal by 1.5 times compared to a Pt electrode. By anchoring specific aptamers on the photoanode, the proposed PFC aptasensor for MC-LR detection presented a linear range from 0.5 × 10² to 4 × 10⁵ pmol/L with a low detection limit of 19.45 pmol/L, which also has good sensitivity and stability for the detection of actual water samples.

This work proposed a dual-photoelectrode PFC by coupling a signal amplification of a Z-scheme photocathode, which exhibited fabulous photoelectric activity and high output power. This work may spark interest in designing new self-powered sensing devices for sensitive and convenient environmental monitoring.