Photoelectrochemical (PEC) efficiency for water splitting is severely
restricted by the high charge recombination and sluggish kinetics of
the oxygen evolution reaction (OER). Herein, we demonstrated the
selectively epitaxial growth of ZnWO4 hole-storage nanoplates on the
top (002) facets of ZnO nanorod arrays, which could efficiently extract
and store the photo-generated holes from ZnO photoanodes. Additionally, after nickel-hydroxide decoration, holes stored in ZnWO4
layers can be rapidly transferred to the surfaces of OER catalysts for
PEC water oxidation. As expected, this photoanode exhibits highly
improved PEC activities for solar water splitting, and a photocurrent
density could be achieved up to 1.7 mA cm 2 (at 1.23 V vs. RHE), more
than three times than that of the pristine ZnO photoanode. Moreover,
an evident negative shift of the onset potential ( 200 mV) as well as
excellent PEC stability has also been observed.