Cobalt-doped carbon nanodots as an interfacial modifier for efficient solar-driven water splitting

Photoelectrochemical water splitting with bismuth vanadate (BiVO 4 ) photoanodes is a promising strategy for solar-driven hydrogen production . However, the unfavorable interfacial charge behavior causes severe charge recombination and photocorrosion issue of BiVO 4 . Herein, cobalt-doped carbon nanodots (CoCDs) are employed for efficient charge extraction due to Co impurity level, which form band alignment with BiVO 4 , as well as accelerate surface reaction. As a result, the obtained CoCDs/BVO photoanode demonstrates an outstanding photocurrent density of 5.26 mA/cm 2 at 1.23 V vs. reversible hydrogen electrode under AM 1.5 G illumination, superior to most BiVO 4 photoanodes with cocatalysts. Carbon nanodots turn out to be an excellent matrix to activate and stabilize Co atoms and tightly anchor onto BiVO 4 , which makes them good interfacial modifier. This work paves an avenue for the optimization of semiconductor/liquid interface and the application of carbon nanomaterials in photoelectrodes.