Fully blossomed WO3/BiVO4 structure obtained via active facet engineering of patterned FTO for highly efficient Water splitting

[Display omitted] •Patterned FTO not only has the effect of pattern, but also becomes suitable for PEC-PSC tandem cell and energy field due to transparency and cheap.•This study suggests a possible method of facet engineering, even when using the same synthetic method, facilitated by the use of a patterned FTO.•As the active facet becomes more diverse, the band structure is altered and the PEC efficiency is increased by about 34%. Materials with anisotropic properties have different electronic structures and photoelectrochemical (PEC) performance depending on the facet. Herein, we controlled the morphology of WO3 nanoflakes, and the ratio of the revealed WO3 facet using patterned F-doped SnO2 fabrication by means of direct printing. In the case of WO3 NF synthesized on patterned FTO (FB-WO3/BiVO4), the proportion of the (002) facet decreased and that of the (200) and (020) facets increased in comparison to the case when NF were synthesized on flat FTO (B-WO3/BiVO4). As the facet ratio changed, the band structure and efficiency changed. The photocurrent density of FB-WO3/BiVO4 was 1.50 mA/cm2, which was 34% higher than that of B-WO3/BiVO4 (1.12 mA/cm2) at 1.23 VRHE. Our results indicate that the efficiency of PEC water splitting can be increased by engineering the exposed facet according to the shape of the substrate, rather than varying the synthetic method.