Etched BiVO4 photocatalyst with charge separation efficiency exceeding 90%

Charge separation of particulate photocatalysts has been considered as the rate-determining step in artificial photocatalysis since the finding of Honda-Fujishima effect, whose efficiency is generally much lower than that of natural photosynthesis. To approach its upper limit, it requires the photoexcited electrons and holes be efficiently transferred to the spatially separated redox reaction sites over a single photocatalyst particle. Herein, it is demonstrated the spatial charge separation among facets of BiVO₄:Mo can be notably promoted by creating an electron transfer layer. It not only favors electrons to transfer to its surface, but also promotes the built-in electric field intensity of the inter-facet junction by over 10 times. Consequently, the charge separation efficiency of the modified BiVO₄:Mo with loading of CoFeO_x oxidation cocatalyst exceeds 90% at 420 nm, comparable to that of the natural photosynthesis system, over which notably enhanced photocatalytic activities are achieved. Our findings demonstrate the effectiveness of electron transfer layer in intensifying charge separation of particulate photocatalysts.