Visible-light-induced water splitting on a hierarchically constructed Z-scheme photocatalyst composed of zinc rhodium oxide and bismuth vanadate

Precise control of the interface in a solid-state heterojunction Z-scheme photocatalyst is important for achieving the intended photocatalytic activity. Herein, we have designed a photocatalyst with a hierarchical structure by photodepositing gold (Au) on the (040) facet of decahedral bismuth vanadate (BiVO 4 ) and then loading zinc rhodium oxide (ZnRh 2 O 4 ) on the Au surface. Owing to the facet-dependent charge separation property of the decahedral BiVO 4 , photoexcited electrons in BiVO 4 accumulate at the (040) facet and then transfer to Au, which acts as a solid electron mediator, to combine with holes of ZnRh 2 O 4 . Utilizing the thus-constructed Z-scheme photocatalyst (ZnRh 2 O 4 /Au/BiVO 4 ), the simultaneous liberation of hydrogen (H 2 ) and oxygen (O 2 ) from water at a molar ratio of 2 : 1 was achieved under irradiation with visible light up to a wavelength of 540 nm, whereas neither H 2 nor O 2 was produced when Au was deposited randomly on the BiVO 4 surface. This study provides insight into the rational design of a solid-state Z-scheme photocatalyst using facet-controlled nanoparticles to enhance photocatalytic activity. A hierarchical Z-scheme photocatalyst composed of BiVO 4 , ZnRh 2 O 4 , and Au was synthesized for visible-light-induced water splitting.