Dec 4, 2024
8:00pm - 10:00pm
Hynes, Level 1, Hall A
Kun Woong Lee1,Dong Su Kim1,Hyung Koun Cho1
Sungkyunkwan University1
Photoelectrochemical (PEC) cells for water splitting have garnered significant interest as a promising solar-to-energy conversion technology. Bismuth vanadate (BiVO
4), a key photoanode material, offers numerous advantages but suffers from surface defects and photo-corrosion instability. To address these challenges, we introduce an innovative passivation strategy. Recognizing the role of V
5+ ion dissolution in photo-corrosion, we propose a surface photoelectrochemical reduction-oxidation technology that transforms detrimental photo-corrosion into beneficial photo-oxidation by strategically introducing V
5+ and H
2O
2 into the photoelectrochemical deposition electrolyte. This approach induces a surface phase transition of metal, resulting in the formation of an ultrathin and atomically controllable vanadium dioxide (VO
2) photoelectrochemical protective layer that enhances conductivity.
Characterization of the BiVO
4/VO
2 photoanodes reveals enhanced charge transport (86%) and efficient transfer of photogenerated carriers (95%) through the VO
2 protection layer. This advancement enables near-ideal performance, high stability, and exceptional durability. BiVO
4/VO
2/CoFeO
x photoanodes exhibit a high photocurrent density of 6.2 mA/cm
2, an onset potential of 0.25 V
RHE, and an applied bias photon-to-current efficiency of 2.4% at 0.62 V
RHE, maintaining vigorous active oxygen evolution over 100 hours.