Rational Design of 3D Hierarchical Ternary SnO₂/TiO₂/BiVO₄ Arrays Photoanode toward Efficient Photoelectrochemical Performance

Abstract

Abstract BiVO 4 as a promising semiconductor absorber is widely investigated as photoanode in photoelectrochemical water splitting. Herein, the rational design of 3D hierarchical ternary SnO 2 /TiO 2 /BiVO 4 arrays is reported as photoanode for photoelectrochemical application, in which the SnO 2 hierarchically hollow microspheres core/nanosheets shell arrays act as conductive skeletons, while the sandwiched TiO 2 and surface BiVO 4 are working as hole blocking layer and light absorber, respectively. Arising to the hierarchically ordered structure and synergistic effect between each component in the composite, the ternary SnO 2 /TiO 2 /BiVO 4 photoanode enables high light harvesting efficiency as well as enhanced charge transport and separation efficiency, yielding a maximum photocurrent density of ≈5.03 mA cm −2 for sulfite oxidation and ≈3.1 mA cm −2 for water oxidation, respectively, measured at 1.23 V versus reversible hydrogen electrode under simulated air mass (AM) 1.5 solar light illumination. The results reveal that electrode design and interface engineering play important roles on the overall PEC performance.