Rational Design of Branched WO3 Nanorods Decorated with BiVO4 Nanoparticles by All-Solution Processing for Efficient Photoelectrochemical Water Splitting

The formation of heterostructure between BiVO 4 and WO 3 is a promising strategy to design a high-performance photoanode. In this study, we prepared the highly crystalline branched WO 3 nanorods decorated with BiVO 4 nanoparticles by all-solution processes and achieved high photoelectrochemical (PEC) performances through the morphological design of WO 3 bottom layer and BiVO 4 decorations. WO 3 nanorods with epitaxially grown nanobranches could be prepared via two-step hydrothermal method, and the BiVO 4 /WO 3 heterostructure was formed by sequent electrodeposition of BiVO 4 nanoparticles on branched WO 3 nanorods. In comparison to bare WO 3 nanorods counterpart, the macelike branched WO 3 nanorods can present the enlarged surface area and improved light trapping properties from the morphological control of WO 3 hierarchical nanostructures, endowing a 32.8% higher photocurrent around 0.85 mA/cm 2 at 1.23 V vs reversible hydrogen electrode (RHE). While decorated with BiVO 4 nanoparticles, the as-fabricated BiVO 4 /macelike WO 3 nanorod heterostructure performs a much improved photocurrent of 3.87 mA/cm 2 at 1.23 V vs RHE. Such a significant enhancement may result from the significantly enhanced light-harvesting and charge separation efficiency. This rational design of heterostructured photoanodes provides a facile, cost-effective, and scalable strategy to improve PEC performances.