Ingenious Dual-Photoelectrode Internal-Driven Self-Powered Sensing Platform for the Power Generation and Simultaneous Microcystin Monitoring Based on the Membrane/Mediator-Free Photofuel Cell

To further heighten solar-energy utilization efficiency could be significantly meaningful for developing useful photoelectric devices. Here, by integrating the nitrogen doped graphene-BiOBr (NG-BiOBr) nanocomposites as a photocathode with titanium dioxide (TiO2) nanoparticles as a photoanode synchronously, a dual-photoelectrode internally driven self-powered sensing platform was fabricated, which can work without an external energy input except for light illumination. In this design, the microcystin-LR (MC-LR) molecules function as the fuel and model analyte as well. Avoiding the use of the costly cathode, this is the first example of the integration of a dual photoresponsive electrode into a photofuel cell for self-powered sensing and paves a luciferous way for efficient multidimension energy conversion. Besides, in order to investigate the detailed sensing process of the self-powered system, the Nyquist curves of the interface are studied between the dual-photoelectrode before and after adding the target MC-LR. The results demonstrated that the photoanode TiO2 contributed to the oxidation of MC-LR under photoirradiation rather than the photocathode. This work not only provides an appealing idea to construct the sensitive and easy-to-use assays of microcystins but also exhibits a successful prototype of a portable and on-site sensor.