Renewable sources of energy are increasingly needed and solar production of hydrogen fuel from water offers significant potential to contribute to these needs.  Bismuth vanadate (BiVO4) has received much interest as a promising visible-light-active photocatalyst for water splitting.  However, it has been reported that photocatalytic performance of BiVO4 is largely limited by slow water oxidation kinetics at the surface.  Previous theoretical studies have been mostly focused on understanding the bulk electronic properties of BiVO4, while the surface structure and the underlying mechanisms for photocatalytic water splitting remain largely unclear.  In this talk, we will present the behavior of excess holes near surface and how they contribute to splitting water on the (001) BiVO4 surface, based on hybrid density functional theory calculations.  Our calculations show that a hole tends to localize on the surface Bi atom, which also turns out to be an energetically favorable site for water adsorption.  A detailed reaction mechanism for hole-assisted water splitting will be discussed, with special attention to the formation and stability of intermediates such as OH, OOH, and HOOH.  The improved understanding would provide invaluable guidance for the rational design of BiVO4-based photocatalysts for high efficiency solar-powered hydrogen generation.

First principles study of photoinduced water splitting on bismuth vanadate

247th National Meeting (2014)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.