Butterfly wing architecture assisted CdS/Au/TiO2 Z-scheme type photocatalytic water splitting

Inspired by natural Z-scheme photosynthesis and black butterfly wing's antireflection morphology, we used the wings of butterfly Papilio nephelus Boisduva as templates to synthesize CdS/Au/TiO2 with butterfly wing architecture. This combination of artificial Z-scheme photosystem and butterfly wing's hierarchical architecture was expected to enhance the light harvesting and water splitting efficiency. The finite-difference time-domain (FDTD) simulation was applied to demonstrate the optical function of the architecture inherited from butterfly wing theoretically, UV-vis spectra and photocatalytic H-2 evolution rates were further recorded to experimentally demonstrate the coupled effect of butterfly wing architecture and CdS/Au/TiO2 Z-scheme components. The FDTD simulation shows that the architecture of the wing scale TiO2 effectively reduced the UV light reflection by about 40%. Meanwhile, the wing scale architecture model exhibited lower UV reflection and transmission in water than those in air, which can be attributed to the stronger diffuse reflection in water. UV-vis spectra and photocatalytic H-2 evolution experiments confirmed that the combination of the wing scale architecture and CdS/Au/TiO2 Z-scheme components contributed to the enhancement of the light harvesting ability and improved the water-splitting efficiency by 200% compared to the plate architecture TiO2. Inspired by Nature, we present a promising way for constructing efficient photocatalysts for hydrogen evolution. Copyright (C) 2013, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.