A carbon dot based metal-free photoelectrochemical cell using O2/H2O redox couple in real seawater

Photochemical devices show great potential in applications ranging from electrical energy storage to future smart grids. Here, we report a metal-free composite film cell based on carbon dots (CDots) and polyaniline (PANI), which could achieve 24/7 discharge and photo-charging in seawater. CDots/PANI film cell has an open-circuit-voltage (OCV) of 0.95 V, a maximum power density of 380 mW m2, and the ability to discharge continuously for 40 h under solar irradiation of AM 1.5 G. It couples the reduction reaction of PANI, and the CDot-catalyzed oxygen reduction reactions (ORR) during discharge. While the light-induced CDot-catalyzed oxygen evolution reaction (OER) and the reduction reaction of PANI during charging. In particular, in-situ TPV tests were used to verify the effect of the light-induced OER and the kinetic properties of the catalyst on the charge transfer at the interface. We believe this research may provide new ideas for sustainable energy conversion and storage. Carbon dots-based film cell can achieve 24/7 discharge and photo-charging in seawater, is capable of storing energy and utilizes the redox reaction of polyaniline, the ORR/OER catalyzed by carbon dots for discharge and charging, and TPV tests were used to explore the OER process and catalytic mechanism during charging.