Thylakoid-Inspired Multishell g-C3N4 Nanocapsules with Enhanced Visible-Light Harvesting and Electron Transfer Properties for High-Efficiency Photocatalysis

Inspired by the orderly stacked nanostructure and highly integrated function of thylakoids in a natural photosynthesis system, multishell g-C3N4 (MSCN) nanocapsule photocatalysts have been prepared by SiO2 hard template with different shell layers. The resultant triple-shell g-C3N4 (TSCN) nanocapsules display superior photocatalysis performance to single-shell and double-shell counterparts owing to excellent visible-light harvesting and electron transfer properties. Specially, with the increase of the shell layer number, light harvesting is greatly enhanced. There is an increase of the entire visible range absorption arising from the multiple scattering and reflection of the incident light within multishell nanoarchitectures as well as the light transmission within the porous thin shells, and an increase of absorption edge arising from the decreased quantum size effect. The electron transfer is greatly accelerated by the mesopores in the thin shells as nanoconduits and the high specific surface area of TSCN (310.7 m2 g-1). With the tailored hierarchical nanostructure features, TSCN exhibits a superior visible-light H2-generation activity of 630 μmol h-1 g-1 (> 420 nm), which is among one of the most efficient metal-free g-C3N4 photocatalysts. This study demonstrates a bioinspired approach to the rational design of high-performance nanostructured visible-light photocatalysts.