WO3 mesocrystal-assisted photoelectrochemical activity of BiVO4

Abstract

Self-assembled nanocomposites have gained much attention over the past decade due to their intriguing properties and functionalities. In this work, we developed a self-assembled nanocomposite photoanode composed of an epitaxial BiVO4 matrix embedded with WO3 mesocrystals for photoelectrochemical (PEC) applications in the visible-light regime. The orientation of the crystal facet and interface provides a superior template to understand the intimate contact between the two constituent phases. We demonstrate that the interfacial coupling of the mesocrystal and matrix improves the separation of photoexcited carriers and the properties of charge transfer, resulting in a greatly enhanced PEC performance compared with their parent compounds. The current study demonstrates that the utilization of the interface-to-volume ratio to optimize charge interactions in the nanocomposite is essential for the advanced design of novel mesocrystal-embedded nanocomposite photoelectrodes. Optimizing how two photocatalysts contact each other inside an amalgamated crystal may enhance solar energy conversion strategies. Bismuth vanadium oxide (BiVO4) is a bright yellow pigment that readily turns photons into electronic charges, which can be used to split water into hydrogen and oxygen gas. The team of Ying-Hao Chu from Taiwan's National Chiao Tung University has now found that embedding tungsten oxide (WO3) nanostructures into BiVO4 crystals makes it easier for photogenerated carriers to reach their target. Using pulsed laser deposition, the researchers grew bamboo-shaped nanotubes inside a BiVO4 matrix to produce numerous heterointerfaces. Band structure analysis and transport measurements showed that the improved charge separation at these interfaces provided more carriers for catalytic water splitting. The material's tunable structure makes it a promising tool for understanding surface-to-volume effects in other nanocomposites. We developed a self-assembled nanocomposite photoanode composed of epitaxial BiVO4 (BVO) matrix embedded with WO3 (WO) mesocrystal for photoelectrochemical (PEC) water splitting in the visible-light regime. The well-defined WO3-BiVO4 interface and controllable thickness provide a template for the fundamental understanding of photoactivity in the nanocomposite. The interfacial coupling of the mesocrystal and matrix improves the separation of photoexcited carriers and the properties of charge transfer, resulting in a significantly enhanced PEC performance. The utilization of the interface-to-volume ratio to optimize the charge interaction of the nanocomposite is essential for the advance design of novel mesocrystal-embedded nanocomposite photoelectrodes.