P-N depleted bulk BiOBr/α-Fe2O3 heterojunctions applied for unbiased solar water splitting.

P-N depleted bulk BiOBr/α-Fe2O3 heterojunction (DBH) nanostructures with the growth of (001) BiOBr facets were prepared via a simple hydrothermal method. BiOBr possesses an average thickness of around 50 nm and shows preferential exposure of the (001) facets. α-Fe2O3 nanoparticles, with an average diameter of 5 nm, are attached on the surface of BiOBr as 20-50 nm clusters with an intimate contact interface. Such DBH nanostructures show high hydrogen evolution, and 193 mmol g-1 of H2 is produced with DBH containing 1 wt% Pt, which is 6.3 times higher than that of α-Fe2O3 nanoparticles. The structural features of DBH are considered to be important to obtain attractive properties in photocatalytic water splitting.