Unveiling the intrinsic band alignment and robust water oxidation features of hierarchical BiVO4 phase junction

Bismuth vanadate (BiVO4) has been one of the most extensively investigated materials in photocatalytic fields owing to its low cost and high performance. Despite much available evidences about its band alignment and photogenerated carrier migration, a convincing explanation of how photogenerated carrier migration occurs in its polymorph phase junction as well as its exact electronic structure has remained elusive. Herein, we designed a high-quality hierarchical tzBiVO4/msBiVO4 phase junction to elucidate the photogenerated carrier migration process and its correlated band alignment. Via the X-ray photoelectron spectroscopy (XPS) and the density functional theory (DFT) calculations, we unveil that a particular band alignment containing Z-scheme and type-II features exists between tzBiVO4 and msBiVO4, where the tzBiVO4 component in tzBiVO4/msBiVO4 showing a higher collecting and oxidizing ability of the photogenerated holes at the designed interface. Importantly, this study offers a new understanding of the BiVO4 atomistic nature of bonding, electronic structure and their related photocatalytic nature.