Patterning p‐Type and n‐Type BiVO ₄ for Solar‐Driven Water Splitting

ABSTRACT

Photocatalytic water splitting is primarily hindered by recombination of photoexcited charge carriers and the co‐occurrence of surface reverse reactions. Heterostructured photocatalysts with directional, efficient Z‐scheme charge transfer are therefore highly desirable to spatially separate photoexcited carriers for efficient overall water splitting. Herein, a patterned BiVO ₄ photoactive film consisting of alternating stripes of p‐type tetragonal zircon BiVO ₄ (t‐BVO) and n‐type monoclinic scheelite BiVO ₄ (m‐BVO) was fabricated on a fluorine‐doped tin oxide (FTO) conductive substrate via photolithography. The FTO layer mediates efficient Z‐scheme charge transfer between neighboring stripes, directing photogenerated electrons and holes to the t‐BVO and m‐BVO stripes, respectively. This spatial separation suppresses detrimental charge recombination and reverse reactions. Consequently, Rh@CrO _x and MnO _x co‐catalysts are selectively photodeposited onto the t‐BVO and m‐BVO stripes to facilitate hydrogen and oxygen evolution. Under full‐spectrum irradiation, the patterned panel achieves stoichiometric overall water splitting (H ₂ /O ₂ ≈ 2:1), producing 1.77 mmol·m ⁻² H ₂ and 0.84 mmol·m ⁻² O ₂ within 1 h—a fourfold enhancement over the unpatterned control. This work demonstrates that ordered semiconductors patterning is an effective strategy to steer charge separation and boost photocatalytic performance.