ZnFe O Dendrite/SnO Helix 3D Hetero-Structure Photoanodes for Enhanced Photoelectrochemical Water Splitting: Triple Functions of SnO Nanohelix

An array of SnO nanohelix structures is employed to fabricate a SnO helix@ZnFe O dendrite core-shell 3D heterostructure photoanode for photoelectrochemical (PEC) water splitting. The SnO helix provides triple critical functions to enhance the PEC performance of the photoanode. First, it scatters the incident light to achieve a higher light harvesting efficiency. Second, it provides a facile electron pathway as an electron transfer layer (ETL) while blocking hole transport to mitigate charge recombination in the bulk of ZnFe O . Finally, it becomes a template for the formation of ZnFe O dendrite nanostructure shell. The ZnFe O dendrite/SnO helix photoanode exhibits a remarkable increase in incident photon-to-electron conversion efficiency compared to unmodified ZnFe O with no ETL and modified one with "flat" SnO ETL. The surface of the ZnFe O /SnO helix photoanode is further modified with TiO passivation layer and NiFeO oxygen evolution co-catalyst to achieve one of the best PEC performances among reported ZnFe O -based photoanodes.