Biotemplated g-C3N4/Au Periodic Hierarchical Structures for the Enhancement of Photocatalytic CO2 Reduction with Localized Surface Plasmon Resonance

Graphitic carbon nitride (g-C3N4) is a promising photocatalyst for CO2 reduction to alleviate the greenhouse effect. However, the low light absorption, small specific surface area, and rapid charge recombination limit the photocatalytic efficiency of g-C3N4 Herein, we demonstrate a bioinspired nanoarchitecturing strategy to significantly improve the light harvesting and charge separation of the g-C3N4/Au composite, as proven by the remarkable photocatalytic CO2 reduction. Specifically, a biotemplating approach is employed to transfer the sophisticated hierarchical structures and the related light-harvesting functionality of Troides helena butterfly wings to the g-C3N4/Au composite. The resulting g-C3N4/Au composite shows high photocatalytic efficiency under UV-visible excitation with triethanolamine as the sacrificial agent. The yields of CO and CH4 are 331.57 and 39.71 mu mol/g/h, respectively, which are similar to 36 times and similar to 88 times that of pure g-C3N4 under the same conditions. Detailed experiments and the finite-difference time-domain method suggest that the superb photocatalytic activity should be ascribed to the unique periodic hierarchical structure which assists the light absorption and the localized surface plasmon resonance for promoted charge separation in addition to the more effective CO2 diffusion and larger specific surface area. Our work provides a new path for the design and optimization of photocatalysts based on biological structures that are usually unattainable artificially.

Automated summary

The study demonstrates a bioinspired nanoarchitecturing strategy to improve the light harvesting and charge separation of g-C3N4/Au composite, resulting in enhanced photocatalytic CO2 reduction efficiency. The composite exhibits high photocatalytic activity under UV-visible excitation, with significantly increased yields of CO and CH4 compared to pure g-C3N4.