Heteroepitaxial approach to explore charge dynamics across Au/BiVO4 interface for photoactivity enhancement. (July 2015) - Van, Chien Nguyen
Abstract: Heterostructure provides a powerful route in manipulating electrical transport, optical response, electrolytic water splitting and water treatment of complex oxides. As a model for noble metal/ complex oxide heterostructures, we have successfully prepared Au/BiVO4 (BVO) heterostructures in which the Au nanoparticles (NPs) with various sizes and densities were uniformly deposited on the {001} facets of epitaxial BVO thin films. The heterostructures exhibit significantly enhanced photoactivities in both dye degradation and electrolytic water splitting. By employing X-ray photoelectron spectroscopy, the energy band alignment of Au/BVO heterojunction suggests a charge separation at their interfaces, that can manipulate the photoexcited electron–hole pairs and photocatalytic efficiency of the heterostructures. Photogenerated carrier injection, which mainly affects the photoactivity of photocatalysis, was detected across Au/BVO interfaces by ultrafast dynamics spectroscopy. This study delivers a general approach to probe and understand the photochemistry of noble metal-complex oxide heterostructures for photoconversion applications. Graphical abstract: Highlights: Crystal Au NPs with good control of size and density were deposited on epitaxial BVO film Energy band alignment of Au/BVO heterojuction can be tuned by controlling Au NPs size and density The photoactivity enhancement of the Au/BVO is due to effective interfacial charge separation