Modification of BiVO4 with partially covered α-Fe2O3 spindles serving as hole-transport channels for significantly improved photoelectrochemical performance

Here, we constructed a BiVO4/Fe2O3 heterostructure using a simple solution dry-out method, in which MIL53(Fe) was used as the precursor of Fe2O3. After the calcining treatment, MIL-53(Fe) polyhedrons were transformed to Fe2O3 spindles. A firm combination between BiVO4 and Fe2O3 would be achieved. Since the dimension of Fe2O3 spindles was larger than the thickness of BiVO4 films, a unique BiVO4 photoanode modified with partially covered Fe2O3 (PC-Fe2O3) spindles was produced, in which Fe2O3 constituted the hole-transport channels. Under light illumination, both the photo-excited electrons and the holes would transfer from BiVO4 to Fe2O3. The electrons migrated to the counterpart to induce the reduction reaction while the holes took part in the oxidation reaction on the exposed part of Fe2O3. As a result, the unique BiVO4/PC-Fe2O3 heterostructure exhibited higher PEC performance than other BiVO4/Fe2O3 nanocomposites reported in previous literatures. This work provides a novel strategy to address the intrinsic drawbacks of type-I heterostructures.