Vertical 3D Printed Forest‐Inspired Hierarchical Plasmonic Superstructure for Photocatalysis

Abstract Efficient light‐harvesting is of significant importance to achieve high solar energy utilization efficiency for various solar‐driven technologies. Compared with a 2D planar structure, a 3D plasmonic structure can largely increase the light adsorption/interaction areas and also utilizes the plasmonic effect to achieve much higher light utilization efficiency. However, this remains challenging in terms of structural design, reliable manufacturing, and ability to scale up. Herein, inspired by the light absorption strategy of natural forests, a hierarchical plasmonic superstructure is demonstrated composed of vertical TiO 2 pillar arrays (as tree trunks), dense nanorod arrays (as branches), and a large number of plasmonic Au nanoparticles (as leaves). Such a forest‐like plasmonic superstructure can effectively absorb light from the surface plasmonic resonance effects of Au nanoparticles and the multiple scattering of light in the hierarchical branched structure. The strong light absorption and abundant photocatalytic active sites help yield a 15‐fold higher nitrogen photo‐fixation activity than that of the flat TiO 2 films decorated with Au nanoparticles. The study provides an effective strategy to construct 3D plasmonic superstructures with excellent light‐harvesting efficiency and high stability and can be readily applied to a range of light‐driven applications