Understanding Photocharging Effects on Bismuth Vanadate.

Bismuth vanadate (BiVO) is a promising material for photoelectrochemical water oxidation. Recently, it has been shown that "photocharging" BiVO results in an improved water oxidation performance. However, the understanding of how BiVO is being improved has been lacking. Here we study the surface kinetics of BiVO using intensity-modulated photocurrent spectroscopy and show that photocharging BiVO results in both surface and bulk improvements. This result sheds light on how the surface charge transfer and bulk charge transport of BiVO respond to illumination.