Nanoporous BiVO 4 Photoanodes with Dual-Layer Oxygen Evolution Catalysts for Solar Water Splitting

A Boost for Bismuth Vanadate In theory, given its light-absorption spectrum, bismuth vanadate should be an effective photoanode for solar water-splitting. However, in prior studies, few of the “holes” generated upon photoexcitation have persisted long enough to strip electrons from water. Kim and Choi (p. 990 , published online 13 February) now show that the use of a hydrophobic vanadium source in the semiconductor's synthesis results in a high-surface-area morphology with substantially enhanced hole lifetimes. Deposition of two successive catalyst layers enhanced the proportion of holes that reacted with water at the surface, thereby raising the efficiency of the oxygen evolution reaction.