LAUSR

We report on a novel butterfly wing-like WO3/BiVO4 heterojunction for photocatalytic water splitting, in which BiVO4 is the primary visible light-absorber and WO3 acts as an electron conductor. The heterojunction, which is prepared by a one-step sol–gel method, achieves high light absorption and charge separation efficiencies, even without a sacrificial agent, and produces a photocatalytic O2 evolution of 20 μmol h−1 mg−1 under visible light irradiation (λ > 420 nm) and an incident photon-to-current conversion efficiency of ∼10% at 380–450 nm, both at a potential of 1.23 V versus RHE. Compared to planar WO3/BiVO4 heterojunction, the 3D nanostructured WO3/BiVO4 heterojunction shows significantly improved photocatalytic performance due to the quasi-honeycomb structure inherited from the Papilio paris and the efficient separation of the photogenerated charge at the WO3/BiVO4 interface. Synthesis details are discussed, with heterojunction morphologies and structures characterized by field emission scanning electron microscopy and X-ray diffraction.